diff options
Diffstat (limited to 'contrib/ncurses/doc/html/NCURSES-Programming-HOWTO.html')
| -rw-r--r-- | contrib/ncurses/doc/html/NCURSES-Programming-HOWTO.html | 6413 |
1 files changed, 0 insertions, 6413 deletions
diff --git a/contrib/ncurses/doc/html/NCURSES-Programming-HOWTO.html b/contrib/ncurses/doc/html/NCURSES-Programming-HOWTO.html deleted file mode 100644 index 3a1010635ff0..000000000000 --- a/contrib/ncurses/doc/html/NCURSES-Programming-HOWTO.html +++ /dev/null @@ -1,6413 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> -<html> -<head> -<meta name="generator" content= -"HTML Tidy for Linux/x86 (vers 1st December 2004), see www.w3.org"> -<title>NCURSES Programming HOWTO</title> -<meta name="GENERATOR" content= -"Modular DocBook HTML Stylesheet Version 1.7"> -</head> -<body class="ARTICLE" bgcolor="#FFFFFF" text="#000000" link= -"#0000FF" vlink="#840084" alink="#0000FF"> -<div class="ARTICLE"> -<div class="TITLEPAGE"> -<h1 class="TITLE"><a name="AEN2" id="AEN2">NCURSES Programming -HOWTO</a></h1> -<h3 class="AUTHOR"><a name="AEN4" id="AEN4">Pradeep Padala</a></h3> -<div class="AFFILIATION"> -<div class="ADDRESS"> -<p class="ADDRESS"><code class="EMAIL"><<a href= -"mailto:ppadala@gmail.com">ppadala@gmail.com</a>></code></p> -</div> -</div> -<p class="PUBDATE">v1.9, 2005-06-20<br></p> -<div class="REVHISTORY"> -<table width="100%" border="0"> -<tr> -<th align="left" valign="top" colspan="3"><b>Revision -History</b></th> -</tr> -<tr> -<td align="left">Revision 1.9</td> -<td align="left">2005-06-20</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">The license has been changed to the -MIT-style license used by NCURSES. Note that the programs are also -re-licensed under this.</td> -</tr> -<tr> -<td align="left">Revision 1.8</td> -<td align="left">2005-06-17</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Lots of updates. Added references and -perl examples. Changes to examples. Many grammatical and stylistic -changes to the content. Changes to NCURSES history.</td> -</tr> -<tr> -<td align="left">Revision 1.7.1</td> -<td align="left">2002-06-25</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Added a README file for building and -instructions for building from source.</td> -</tr> -<tr> -<td align="left">Revision 1.7</td> -<td align="left">2002-06-25</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Added "Other formats" section and made -a lot of fancy changes to the programs. Inlining of programs is -gone.</td> -</tr> -<tr> -<td align="left">Revision 1.6.1</td> -<td align="left">2002-02-24</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Removed the old Changelog section, -cleaned the makefiles</td> -</tr> -<tr> -<td align="left">Revision 1.6</td> -<td align="left">2002-02-16</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Corrected a lot of spelling mistakes, -added ACS variables section</td> -</tr> -<tr> -<td align="left">Revision 1.5</td> -<td align="left">2002-01-05</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Changed structure to present proper -TOC</td> -</tr> -<tr> -<td align="left">Revision 1.3.1</td> -<td align="left">2001-07-26</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Corrected maintainers paragraph, -Corrected stable release number</td> -</tr> -<tr> -<td align="left">Revision 1.3</td> -<td align="left">2001-07-24</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Added copyright notices to main -document (LDP license) and programs (GPL), Corrected -printw_example.</td> -</tr> -<tr> -<td align="left">Revision 1.2</td> -<td align="left">2001-06-05</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Incorporated ravi's changes. Mainly to -introduction, menu, form, justforfun sections</td> -</tr> -<tr> -<td align="left">Revision 1.1</td> -<td align="left">2001-05-22</td> -<td align="left">Revised by: ppadala</td> -</tr> -<tr> -<td align="left" colspan="3">Added "a word about window" section, -Added scanw_example.</td> -</tr> -</table> -</div> -<div> -<div class="ABSTRACT"><a name="AEN67" id="AEN67"></a> -<p><em>This document is intended to be an "All in One" guide for -programming with ncurses and its sister libraries. We graduate from -a simple "Hello World" program to more complex form manipulation. -No prior experience in ncurses is assumed. Send comments to -<a href="mailto:ppadala@gmail.com" target="_top">this -address</a></em></p> -</div> -</div> -<hr></div> -<div class="TOC"> -<dl> -<dt><b>Table of Contents</b></dt> -<dt>1. <a href="#INTRO">Introduction</a></dt> -<dd> -<dl> -<dt>1.1. <a href="#WHATIS">What is NCURSES?</a></dt> -<dt>1.2. <a href="#WHATCANWEDO">What we can do with -NCURSES</a></dt> -<dt>1.3. <a href="#WHERETOGETIT">Where to get it</a></dt> -<dt>1.4. <a href="#PURPOSE">Purpose/Scope of the document</a></dt> -<dt>1.5. <a href="#ABOUTPROGRAMS">About the Programs</a></dt> -<dt>1.6. <a href="#OTHERFORMATS">Other Formats of the -document</a></dt> -<dt>1.7. <a href="#CREDITS">Credits</a></dt> -<dt>1.8. <a href="#WISHLIST">Wish List</a></dt> -<dt>1.9. <a href="#COPYRIGHT">Copyright</a></dt> -</dl> -</dd> -<dt>2. <a href="#HELLOWORLD">Hello World !!!</a></dt> -<dd> -<dl> -<dt>2.1. <a href="#COMPILECURSES">Compiling With the NCURSES -Library</a></dt> -<dt>2.2. <a href="#DISSECTION">Dissection</a></dt> -</dl> -</dd> -<dt>3. <a href="#GORY">The Gory Details</a></dt> -<dt>4. <a href="#INIT">Initialization</a></dt> -<dd> -<dl> -<dt>4.1. <a href="#ABOUTINIT">Initialization functions</a></dt> -<dt>4.2. <a href="#RAWCBREAK">raw() and cbreak()</a></dt> -<dt>4.3. <a href="#ECHONOECHO">echo() and noecho()</a></dt> -<dt>4.4. <a href="#KEYPAD">keypad()</a></dt> -<dt>4.5. <a href="#HALFDELAY">halfdelay()</a></dt> -<dt>4.6. <a href="#MISCINIT">Miscellaneous Initialization -functions</a></dt> -<dt>4.7. <a href="#INITEX">An Example</a></dt> -</dl> -</dd> -<dt>5. <a href="#AWORDWINDOWS">A Word about Windows</a></dt> -<dt>6. <a href="#PRINTW">Output functions</a></dt> -<dd> -<dl> -<dt>6.1. <a href="#ADDCHCLASS">addch() class of functions</a></dt> -<dt>6.2. <a href="#AEN298">mvaddch(), waddch() and -mvwaddch()</a></dt> -<dt>6.3. <a href="#PRINTWCLASS">printw() class of -functions</a></dt> -<dt>6.4. <a href="#ADDSTRCLASS">addstr() class of -functions</a></dt> -<dt>6.5. <a href="#ACAUTION">A word of caution</a></dt> -</dl> -</dd> -<dt>7. <a href="#SCANW">Input functions</a></dt> -<dd> -<dl> -<dt>7.1. <a href="#GETCHCLASS">getch() class of functions</a></dt> -<dt>7.2. <a href="#SCANWCLASS">scanw() class of functions</a></dt> -<dt>7.3. <a href="#GETSTRCLASS">getstr() class of -functions</a></dt> -<dt>7.4. <a href="#GETSTREX">Some examples</a></dt> -</dl> -</dd> -<dt>8. <a href="#ATTRIB">Attributes</a></dt> -<dd> -<dl> -<dt>8.1. <a href="#ATTRIBDETAILS">The details</a></dt> -<dt>8.2. <a href="#ATTRONVSATTRSET">attron() vs attrset()</a></dt> -<dt>8.3. <a href="#ATTR_GET">attr_get()</a></dt> -<dt>8.4. <a href="#ATTR_FUNCS">attr_ functions</a></dt> -<dt>8.5. <a href="#WATTRFUNCS">wattr functions</a></dt> -<dt>8.6. <a href="#CHGAT">chgat() functions</a></dt> -</dl> -</dd> -<dt>9. <a href="#WINDOWS">Windows</a></dt> -<dd> -<dl> -<dt>9.1. <a href="#WINDOWBASICS">The basics</a></dt> -<dt>9.2. <a href="#LETBEWINDOW">Let there be a Window !!!</a></dt> -<dt>9.3. <a href="#BORDEREXEXPL">Explanation</a></dt> -<dt>9.4. <a href="#OTHERSTUFF">The other stuff in the -example</a></dt> -<dt>9.5. <a href="#OTHERBORDERFUNCS">Other Border -functions</a></dt> -</dl> -</dd> -<dt>10. <a href="#COLOR">Colors</a></dt> -<dd> -<dl> -<dt>10.1. <a href="#COLORBASICS">The basics</a></dt> -<dt>10.2. <a href="#CHANGECOLORDEFS">Changing Color -Definitions</a></dt> -<dt>10.3. <a href="#COLORCONTENT">Color Content</a></dt> -</dl> -</dd> -<dt>11. <a href="#KEYS">Interfacing with the key board</a></dt> -<dd> -<dl> -<dt>11.1. <a href="#KEYSBASICS">The Basics</a></dt> -<dt>11.2. <a href="#SIMPLEKEYEX">A Simple Key Usage -example</a></dt> -</dl> -</dd> -<dt>12. <a href="#MOUSE">Interfacing with the mouse</a></dt> -<dd> -<dl> -<dt>12.1. <a href="#MOUSEBASICS">The Basics</a></dt> -<dt>12.2. <a href="#GETTINGEVENTS">Getting the events</a></dt> -<dt>12.3. <a href="#MOUSETOGETHER">Putting it all Together</a></dt> -<dt>12.4. <a href="#MISCMOUSEFUNCS">Miscellaneous -Functions</a></dt> -</dl> -</dd> -<dt>13. <a href="#SCREEN">Screen Manipulation</a></dt> -<dd> -<dl> -<dt>13.1. <a href="#GETYX">getyx() functions</a></dt> -<dt>13.2. <a href="#SCREENDUMP">Screen Dumping</a></dt> -<dt>13.3. <a href="#WINDOWDUMP">Window Dumping</a></dt> -</dl> -</dd> -<dt>14. <a href="#MISC">Miscellaneous features</a></dt> -<dd> -<dl> -<dt>14.1. <a href="#CURSSET">curs_set()</a></dt> -<dt>14.2. <a href="#TEMPLEAVE">Temporarily Leaving Curses -mode</a></dt> -<dt>14.3. <a href="#ACSVARS">ACS_ variables</a></dt> -</dl> -</dd> -<dt>15. <a href="#OTHERLIB">Other libraries</a></dt> -<dt>16. <a href="#PANELS">Panel Library</a></dt> -<dd> -<dl> -<dt>16.1. <a href="#PANELBASICS">The Basics</a></dt> -<dt>16.2. <a href="#COMPILEPANELS">Compiling With the Panels -Library</a></dt> -<dt>16.3. <a href="#PANELBROWSING">Panel Window Browsing</a></dt> -<dt>16.4. <a href="#USERPTRUSING">Using User Pointers</a></dt> -<dt>16.5. <a href="#PANELMOVERESIZE">Moving and Resizing -Panels</a></dt> -<dt>16.6. <a href="#PANELSHOWHIDE">Hiding and Showing -Panels</a></dt> -<dt>16.7. <a href="#PANELABOVE">panel_above() and panel_below() -Functions</a></dt> -</dl> -</dd> -<dt>17. <a href="#MENUS">Menus Library</a></dt> -<dd> -<dl> -<dt>17.1. <a href="#MENUBASICS">The Basics</a></dt> -<dt>17.2. <a href="#COMPILEMENUS">Compiling With the Menu -Library</a></dt> -<dt>17.3. <a href="#MENUDRIVER">Menu Driver: The work horse of the -menu system</a></dt> -<dt>17.4. <a href="#MENUWINDOWS">Menu Windows</a></dt> -<dt>17.5. <a href="#SCROLLMENUS">Scrolling Menus</a></dt> -<dt>17.6. <a href="#MULTICOLUMN">Multi Columnar Menus</a></dt> -<dt>17.7. <a href="#MULTIVALUEMENUS">Multi Valued Menus</a></dt> -<dt>17.8. <a href="#MENUOPT">Menu Options</a></dt> -<dt>17.9. <a href="#MENUUSERPTR">The useful User Pointer</a></dt> -</dl> -</dd> -<dt>18. <a href="#FORMS">Forms Library</a></dt> -<dd> -<dl> -<dt>18.1. <a href="#FORMBASICS">The Basics</a></dt> -<dt>18.2. <a href="#COMPILEFORMS">Compiling With the Forms -Library</a></dt> -<dt>18.3. <a href="#PLAYFIELDS">Playing with Fields</a></dt> -<dt>18.4. <a href="#FORMWINDOWS">Form Windows</a></dt> -<dt>18.5. <a href="#FILEDVALIDATE">Field Validation</a></dt> -<dt>18.6. <a href="#FORMDRIVER">Form Driver: The work horse of the -forms system</a></dt> -</dl> -</dd> -<dt>19. <a href="#TOOLS">Tools and Widget Libraries</a></dt> -<dd> -<dl> -<dt>19.1. <a href="#CDK">CDK (Curses Development Kit)</a></dt> -<dt>19.2. <a href="#DIALOG">The dialog</a></dt> -<dt>19.3. <a href="#PERLCURSES">Perl Curses Modules CURSES::FORM -and CURSES::WIDGETS</a></dt> -</dl> -</dd> -<dt>20. <a href="#JUSTFORFUN">Just For Fun !!!</a></dt> -<dd> -<dl> -<dt>20.1. <a href="#GAMEOFLIFE">The Game of Life</a></dt> -<dt>20.2. <a href="#MAGIC">Magic Square</a></dt> -<dt>20.3. <a href="#HANOI">Towers of Hanoi</a></dt> -<dt>20.4. <a href="#QUEENS">Queens Puzzle</a></dt> -<dt>20.5. <a href="#SHUFFLE">Shuffle</a></dt> -<dt>20.6. <a href="#TT">Typing Tutor</a></dt> -</dl> -</dd> -<dt>21. <a href="#REF">References</a></dt> -</dl> -</div> -<div class="SECT1"> -<h2 class="SECT1"><a name="INTRO" id="INTRO">1. -Introduction</a></h2> -<p>In the olden days of teletype terminals, terminals were away -from computers and were connected to them through serial cables. -The terminals could be configured by sending a series of bytes. All -the capabilities (such as moving the cursor to a new location, -erasing part of the screen, scrolling the screen, changing modes -etc.) of terminals could be accessed through these series of bytes. -These control seeuqnces are usually called escape sequences, -because they start with an escape(0x1B) character. Even today, with -proper emulation, we can send escape sequences to the emulator and -achieve the same effect on a terminal window.</p> -<p>Suppose you wanted to print a line in color. Try typing this on -your console.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000">echo "^[[0;31;40mIn Color"</font> -</pre></td> -</tr> -</table> -<p>The first character is an escape character, which looks like two -characters ^ and [. To be able to print it, you have to press -CTRL+V and then the ESC key. All the others are normal printable -characters. You should be able to see the string "In Color" in red. -It stays that way and to revert back to the original mode type -this.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000">echo "^[[0;37;40m"</font> -</pre></td> -</tr> -</table> -<p>Now, what do these magic characters mean? Difficult to -comprehend? They might even be different for different terminals. -So the designers of UNIX invented a mechanism named <var class= -"LITERAL">termcap</var>. It is a file that lists all the -capabilities of a particular terminal, along with the escape -sequences needed to achieve a particular effect. In the later -years, this was replaced by <var class="LITERAL">terminfo</var>. -Without delving too much into details, this mechanism allows -application programs to query the terminfo database and obtain the -control characters to be sent to a terminal or terminal -emulator.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="WHATIS" id="WHATIS">1.1. What is -NCURSES?</a></h3> -<p>You might be wondering, what the import of all this technical -gibberish is. In the above scenario, every application program is -supposed to query the terminfo and perform the necessary stuff -(sending control characters etc.). It soon became difficult to -manage this complexity and this gave birth to 'CURSES'. Curses is a -pun on the name "cursor optimization". The Curses library forms a -wrapper over working with raw terminal codes, and provides highly -flexible and efficient API (Application Programming Interface). It -provides functions to move the cursor, create windows, produce -colors, play with mouse etc. The application programs need not -worry about the underlying terminal capabilities.</p> -<p>So what is NCURSES? NCURSES is a clone of the original System V -Release 4.0 (SVr4) curses. It is a freely distributable library, -fully compatible with older version of curses. In short, it is a -library of functions that manages an application's display on -character-cell terminals. In the remainder of the document, the -terms curses and ncurses are used interchangeably.</p> -<p>A detailed history of NCURSES can be found in the NEWS file from -the source distribution. The current package is maintained by -<a href="mailto:dickey@his.com" target="_top">Thomas Dickey</a>. -You can contact the maintainers at <a href= -"mailto:bug-ncurses@gnu.org" target= -"_top">bug-ncurses@gnu.org</a>.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="WHATCANWEDO" id="WHATCANWEDO">1.2. What -we can do with NCURSES</a></h3> -<p>NCURSES not only creates a wrapper over terminal capabilities, -but also gives a robust framework to create nice looking UI (User -Interface)s in text mode. It provides functions to create windows -etc. Its sister libraries panel, menu and form provide an extension -to the basic curses library. These libraries usually come along -with curses. One can create applications that contain multiple -windows, menus, panels and forms. Windows can be managed -independently, can provide 'scrollability' and even can be -hidden.</p> -<p>Menus provide the user with an easy command selection option. -Forms allow the creation of easy-to-use data entry and display -windows. Panels extend the capabilities of ncurses to deal with -overlapping and stacked windows.</p> -<p>These are just some of the basic things we can do with ncurses. -As we move along, We will see all the capabilities of these -libraries.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="WHERETOGETIT" id="WHERETOGETIT">1.3. -Where to get it</a></h3> -<p>All right, now that you know what you can do with ncurses, you -must be rearing to get started. NCURSES is usually shipped with -your installation. In case you don't have the library or want to -compile it on your own, read on.</p> -<p><em>Compiling the package</em></p> -<p>NCURSES can be obtained from <a href= -"ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz" target= -"_top">ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz</a> or any -of the ftp sites mentioned in <a href= -"http://www.gnu.org/order/ftp.html" target= -"_top">http://www.gnu.org/order/ftp.html</a>.</p> -<p>Read the README and INSTALL files for details on to how to -install it. It usually involves the following operations.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> tar zxvf ncurses<version>.tar.gz # unzip and untar the archive - cd ncurses<version> # cd to the directory - ./configure # configure the build according to your - # environment - make # make it - su root # become root - make install # install it</font> -</pre></td> -</tr> -</table> -<p><em>Using the RPM</em></p> -<p>NCURSES RPM can be found and downloaded from <a href= -"http://rpmfind.net" target="_top">http://rpmfind.net</a> . The RPM -can be installed with the following command after becoming -root.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> rpm -i <downloaded rpm></font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PURPOSE" id="PURPOSE">1.4. Purpose/Scope -of the document</a></h3> -<p>This document is intended to be a "All in One" guide for -programming with ncurses and its sister libraries. We graduate from -a simple "Hello World" program to more complex form manipulation. -No prior experience in ncurses is assumed. The writing is informal, -but a lot of detail is provided for each of the examples.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ABOUTPROGRAMS" id="ABOUTPROGRAMS">1.5. -About the Programs</a></h3> -<p>All the programs in the document are available in zipped form -<a href= -"http://www.tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs.tar.gz" -target="_top">here</a>. Unzip and untar it. The directory structure -looks like this.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000">ncurses - | - |----> JustForFun -- just for fun programs - |----> basics -- basic programs - |----> demo -- output files go into this directory after make - | | - | |----> exe -- exe files of all example programs - |----> forms -- programs related to form library - |----> menus -- programs related to menus library - |----> panels -- programs related to panels library - |----> perl -- perl equivalents of the examples (contributed - | by Anuradha Ratnaweera) - |----> Makefile -- the top level Makefile - |----> README -- the top level README file. contains instructions - |----> COPYING -- copyright notice</font> -</pre></td> -</tr> -</table> -<p>The individual directories contain the following files.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000">Description of files in each directory --------------------------------------- -JustForFun - | - |----> hanoi.c -- The Towers of Hanoi Solver - |----> life.c -- The Game of Life demo - |----> magic.c -- An Odd Order Magic Square builder - |----> queens.c -- The famous N-Queens Solver - |----> shuffle.c -- A fun game, if you have time to kill - |----> tt.c -- A very trivial typing tutor - - basics - | - |----> acs_vars.c -- ACS_ variables example - |----> hello_world.c -- Simple "Hello World" Program - |----> init_func_example.c -- Initialization functions example - |----> key_code.c -- Shows the scan code of the key pressed - |----> mouse_menu.c -- A menu accessible by mouse - |----> other_border.c -- Shows usage of other border functions apa - | -- rt from box() - |----> printw_example.c -- A very simple printw() example - |----> scanw_example.c -- A very simple getstr() example - |----> simple_attr.c -- A program that can print a c file with - | -- comments in attribute - |----> simple_color.c -- A simple example demonstrating colors - |----> simple_key.c -- A menu accessible with keyboard UP, DOWN - | -- arrows - |----> temp_leave.c -- Demonstrates temporarily leaving curses mode - |----> win_border.c -- Shows Creation of windows and borders - |----> with_chgat.c -- chgat() usage example - - forms - | - |----> form_attrib.c -- Usage of field attributes - |----> form_options.c -- Usage of field options - |----> form_simple.c -- A simple form example - |----> form_win.c -- Demo of windows associated with forms - - menus - | - |----> menu_attrib.c -- Usage of menu attributes - |----> menu_item_data.c -- Usage of item_name() etc.. functions - |----> menu_multi_column.c -- Creates multi columnar menus - |----> menu_scroll.c -- Demonstrates scrolling capability of menus - |----> menu_simple.c -- A simple menu accessed by arrow keys - |----> menu_toggle.c -- Creates multi valued menus and explains - | -- REQ_TOGGLE_ITEM - |----> menu_userptr.c -- Usage of user pointer - |----> menu_win.c -- Demo of windows associated with menus - - panels - | - |----> panel_browse.c -- Panel browsing through tab. Usage of user - | -- pointer - |----> panel_hide.c -- Hiding and Un hiding of panels - |----> panel_resize.c -- Moving and resizing of panels - |----> panel_simple.c -- A simple panel example - - perl - |----> 01-10.pl -- Perl equivalents of first ten example programs</font> -</pre></td> -</tr> -</table> -<p>There is a top level Makefile included in the main directory. It -builds all the files and puts the ready-to-use exes in demo/exe -directory. You can also do selective make by going into the -corresponding directory. Each directory contains a README file -explaining the purpose of each c file in the directory.</p> -<p>For every example, I have included path name for the file -relative to the examples directory.</p> -<p>If you prefer browsing individual programs, point your browser -to <a href= -"http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/" -target= -"_top">http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/</a></p> -<p>All the programs are released under the same license that is -used by ncurses (MIT-style). This gives you the ability to do -pretty much anything other than claiming them as yours. Feel free -to use them in your programs as appropriate.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="OTHERFORMATS" id="OTHERFORMATS">1.6. -Other Formats of the document</a></h3> -<p>This howto is also availabe in various other formats on the -tldp.org site. Here are the links to other formats of this -document.</p> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="LISTFORMATS" id="LISTFORMATS">1.6.1. -Readily available formats from tldp.org</a></h4> -<ul> -<li> -<p><a href= -"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/pdf/NCURSES-Programming-HOWTO.pdf" -target="_top">Acrobat PDF Format</a></p> -</li> -<li> -<p><a href= -"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/ps/NCURSES-Programming-HOWTO.ps.gz" -target="_top">PostScript Format</a></p> -</li> -<li> -<p><a href= -"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html/NCURSES-Programming-HOWTO-html.tar.gz" -target="_top">In Multiple HTML pages</a></p> -</li> -<li> -<p><a href= -"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/NCURSES-Programming-HOWTO.html" -target="_top">In One big HTML format</a></p> -</li> -</ul> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="BUILDSOURCE" id="BUILDSOURCE">1.6.2. -Building from source</a></h4> -<p>If above links are broken or if you want to experiment with sgml -read on.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> Get both the source and the tar,gzipped programs, available at - http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/ - NCURSES-HOWTO/NCURSES-Programming-HOWTO.sgml - http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/ - NCURSES-HOWTO/ncurses_programs.tar.gz - - Unzip ncurses_programs.tar.gz with - tar zxvf ncurses_programs.tar.gz - - Use jade to create various formats. For example if you just want to create - the multiple html files, you would use - jade -t sgml -i html -d <path to docbook html stylesheet> - NCURSES-Programming-HOWTO.sgml - to get pdf, first create a single html file of the HOWTO with - jade -t sgml -i html -d <path to docbook html stylesheet> -V nochunks - NCURSES-Programming-HOWTO.sgml > NCURSES-ONE-BIG-FILE.html - then use htmldoc to get pdf file with - htmldoc --size universal -t pdf --firstpage p1 -f <output file name.pdf> - NCURSES-ONE-BIG-FILE.html - for ps, you would use - htmldoc --size universal -t ps --firstpage p1 -f <output file name.ps> - NCURSES-ONE-BIG-FILE.html</font> -</pre></td> -</tr> -</table> -<p>See <a href="http://www.tldp.org/LDP/LDP-Author-Guide/" target= -"_top">LDP Author guide</a> for more details. If all else failes, -mail me at <a href="ppadala@gmail.com" target= -"_top">ppadala@gmail.com</a></p> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="CREDITS" id="CREDITS">1.7. -Credits</a></h3> -<p>I thank <a href="mailto:sharath_1@usa.net" target= -"_top">Sharath</a> and Emre Akbas for helping me with few sections. -The introduction was initially written by sharath. I rewrote it -with few excerpts taken from his initial work. Emre helped in -writing printw and scanw sections.</p> -<p>Perl equivalents of the example programs are contributed by -<a href="mailto:Aratnaweera@virtusa.com" target="_top">Anuradha -Ratnaweera</a>.</p> -<p>Then comes <a href="mailto:parimi@ece.arizona.edu" target= -"_top">Ravi Parimi</a>, my dearest friend, who has been on this -project before even one line was written. He constantly bombarded -me with suggestions and patiently reviewed the whole text. He also -checked each program on Linux and Solaris.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="WISHLIST" id="WISHLIST">1.8. Wish -List</a></h3> -<p>This is the wish list, in the order of priority. If you have a -wish or you want to work on completing the wish, mail <a href= -"mailto:ppadala@gmail.com" target="_top">me</a>.</p> -<ul> -<li> -<p>Add examples to last parts of forms section.</p> -</li> -<li> -<p>Prepare a Demo showing all the programs and allow the user to -browse through description of each program. Let the user compile -and see the program in action. A dialog based interface is -preferred.</p> -</li> -<li> -<p>Add debug info. _tracef, _tracemouse stuff.</p> -</li> -<li> -<p>Accessing termcap, terminfo using functions provided by ncurses -package.</p> -</li> -<li> -<p>Working on two terminals simultaneously.</p> -</li> -<li> -<p>Add more stuff to miscellaneous section.</p> -</li> -</ul> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="COPYRIGHT" id="COPYRIGHT">1.9. -Copyright</a></h3> -<p>Copyright © 2001 by Pradeep Padala.</p> -<p>Permission is hereby granted, free of charge, to any person -obtaining a copy of this software and associated documentation -files (the "Software"), to deal in the Software without -restriction, including without limitation the rights to use, copy, -modify, merge, publish, distribute, distribute with modifications, -sublicense, and/or sell copies of the Software, and to permit -persons to whom the Software is furnished to do so, subject to the -following conditions:</p> -<p>The above copyright notice and this permission notice shall be -included in all copies or substantial portions of the Software.</p> -<p>THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, -EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF -MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND -NONINFRINGEMENT. IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE -LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN -ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN -CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE -SOFTWARE.</p> -<p>Except as contained in this notice, the name(s) of the above -copyright holders shall not be used in advertising or otherwise to -promote the sale, use or other dealings in this Software without -prior written authorization.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="HELLOWORLD" id="HELLOWORLD">2. Hello -World !!!</a></h2> -<p>Welcome to the world of curses. Before we plunge into the -library and look into its various features, let's write a simple -program and say hello to the world.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="COMPILECURSES" id="COMPILECURSES">2.1. -Compiling With the NCURSES Library</a></h3> -<p>To use ncurses library functions, you have to include ncurses.h -in your programs. To link the program with ncurses the flag --lncurses should be added.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> #include <ncurses.h> - . - . - . - - compile and link: gcc <program file> -lncurses</font> -</pre></td> -</tr> -</table> -<div class="EXAMPLE"><a name="BHW" id="BHW"></a> -<p><b>Example 1. The Hello World !!! Program</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - -int main() -{ - initscr(); /* Start curses mode */ - printw("Hello World !!!"); /* Print Hello World */ - refresh(); /* Print it on to the real screen */ - getch(); /* Wait for user input */ - endwin(); /* End curses mode */ - - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="DISSECTION" id="DISSECTION">2.2. -Dissection</a></h3> -<p>The above program prints "Hello World !!!" to the screen and -exits. This program shows how to initialize curses and do screen -manipulation and end curses mode. Let's dissect it line by -line.</p> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="ABOUT-INITSCR" id="ABOUT-INITSCR">2.2.1. -About initscr()</a></h4> -<p>The function initscr() initializes the terminal in curses mode. -In some implementations, it clears the screen and presents a blank -screen. To do any screen manipulation using curses package this has -to be called first. This function initializes the curses system and -allocates memory for our present window (called <var class= -"LITERAL">stdscr</var>) and some other data-structures. Under -extreme cases this function might fail due to insufficient memory -to allocate memory for curses library's data structures.</p> -<p>After this is done, we can do a variety of initializations to -customize our curses settings. These details will be explained -<a href="#INIT">later</a> .</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="MYST-REFRESH" id="MYST-REFRESH">2.2.2. -The mysterious refresh()</a></h4> -<p>The next line printw prints the string "Hello World !!!" on to -the screen. This function is analogous to normal printf in all -respects except that it prints the data on a window called stdscr -at the current (y,x) co-ordinates. Since our present co-ordinates -are at 0,0 the string is printed at the left hand corner of the -window.</p> -<p>This brings us to that mysterious refresh(). Well, when we -called printw the data is actually written to an imaginary window, -which is not updated on the screen yet. The job of printw is to -update a few flags and data structures and write the data to a -buffer corresponding to stdscr. In order to show it on the screen, -we need to call refresh() and tell the curses system to dump the -contents on the screen.</p> -<p>The philosophy behind all this is to allow the programmer to do -multiple updates on the imaginary screen or windows and do a -refresh once all his screen update is done. refresh() checks the -window and updates only the portion which has been changed. This -improves performance and offers greater flexibility too. But, it is -sometimes frustrating to beginners. A common mistake committed by -beginners is to forget to call refresh() after they did some update -through printw() class of functions. I still forget to add it -sometimes :-)</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="ABOUT-ENDWIN" id="ABOUT-ENDWIN">2.2.3. -About endwin()</a></h4> -<p>And finally don't forget to end the curses mode. Otherwise your -terminal might behave strangely after the program quits. endwin() -frees the memory taken by curses sub-system and its data structures -and puts the terminal in normal mode. This function must be called -after you are done with the curses mode.</p> -</div> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="GORY" id="GORY">3. The Gory -Details</a></h2> -<p>Now that we have seen how to write a simple curses program let's -get into the details. There are many functions that help customize -what you see on screen and many features which can be put to full -use.</p> -<p>Here we go...</p> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="INIT" id="INIT">4. -Initialization</a></h2> -<p>We now know that to initialize curses system the function -initscr() has to be called. There are functions which can be called -after this initialization to customize our curses session. We may -ask the curses system to set the terminal in raw mode or initialize -color or initialize the mouse etc.. Let's discuss some of the -functions that are normally called immediately after initscr();</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ABOUTINIT" id="ABOUTINIT">4.1. -Initialization functions</a></h3> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="RAWCBREAK" id="RAWCBREAK">4.2. raw() and -cbreak()</a></h3> -<p>Normally the terminal driver buffers the characters a user types -until a new line or carriage return is encountered. But most -programs require that the characters be available as soon as the -user types them. The above two functions are used to disable line -buffering. The difference between these two functions is in the way -control characters like suspend (CTRL-Z), interrupt and quit -(CTRL-C) are passed to the program. In the raw() mode these -characters are directly passed to the program without generating a -signal. In the <var class="LITERAL">cbreak()</var> mode these -control characters are interpreted as any other character by the -terminal driver. I personally prefer to use raw() as I can exercise -greater control over what the user does.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ECHONOECHO" id="ECHONOECHO">4.3. echo() -and noecho()</a></h3> -<p>These functions control the echoing of characters typed by the -user to the terminal. <var class="LITERAL">noecho()</var> switches -off echoing. The reason you might want to do this is to gain more -control over echoing or to suppress unnecessary echoing while -taking input from the user through the getch() etc. functions. Most -of the interactive programs call <var class= -"LITERAL">noecho()</var> at initialization and do the echoing of -characters in a controlled manner. It gives the programmer the -flexibility of echoing characters at any place in the window -without updating current (y,x) co-ordinates.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="KEYPAD" id="KEYPAD">4.4. -keypad()</a></h3> -<p>This is my favorite initialization function. It enables the -reading of function keys like F1, F2, arrow keys etc. Almost every -interactive program enables this, as arrow keys are a major part of -any User Interface. Do <var class="LITERAL">keypad(stdscr, -TRUE)</var> to enable this feature for the regular screen (stdscr). -You will learn more about key management in later sections of this -document.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="HALFDELAY" id="HALFDELAY">4.5. -halfdelay()</a></h3> -<p>This function, though not used very often, is a useful one at -times. halfdelay()is called to enable the half-delay mode, which is -similar to the cbreak() mode in that characters typed are -immediately available to program. However, it waits for 'X' tenths -of a second for input and then returns ERR, if no input is -available. 'X' is the timeout value passed to the function -halfdelay(). This function is useful when you want to ask the user -for input, and if he doesn't respond with in certain time, we can -do some thing else. One possible example is a timeout at the -password prompt.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MISCINIT" id="MISCINIT">4.6. -Miscellaneous Initialization functions</a></h3> -<p>There are few more functions which are called at initialization -to customize curses behavior. They are not used as extensively as -those mentioned above. Some of them are explained where -appropriate.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="INITEX" id="INITEX">4.7. An -Example</a></h3> -<p>Let's write a program which will clarify the usage of these -functions.</p> -<div class="EXAMPLE"><a name="BINFU" id="BINFU"></a> -<p><b>Example 2. Initialization Function Usage example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - -int main() -{ int ch; - - initscr(); /* Start curses mode */ - raw(); /* Line buffering disabled */ - keypad(stdscr, TRUE); /* We get F1, F2 etc.. */ - noecho(); /* Don't echo() while we do getch */ - - printw("Type any character to see it in bold\n"); - ch = getch(); /* If raw() hadn't been called - * we have to press enter before it - * gets to the program */ - if(ch == KEY_F(1)) /* Without keypad enabled this will */ - printw("F1 Key pressed");/* not get to us either */ - /* Without noecho() some ugly escape - * charachters might have been printed - * on screen */ - else - { printw("The pressed key is "); - attron(A_BOLD); - printw("%c", ch); - attroff(A_BOLD); - } - refresh(); /* Print it on to the real screen */ - getch(); /* Wait for user input */ - endwin(); /* End curses mode */ - - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>This program is self-explanatory. But I used functions which -aren't explained yet. The function <var class= -"LITERAL">getch()</var> is used to get a character from user. It is -equivalent to normal <var class="LITERAL">getchar()</var> except -that we can disable the line buffering to avoid <enter> after -input. Look for more about <var class="LITERAL">getch()</var>and -reading keys in the <a href="#KEYS">key management section</a> . -The functions attron and attroff are used to switch some attributes -on and off respectively. In the example I used them to print the -character in bold. These functions are explained in detail -later.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="AWORDWINDOWS" id="AWORDWINDOWS">5. A -Word about Windows</a></h2> -<p>Before we plunge into the myriad ncurses functions, let me clear -few things about windows. Windows are explained in detail in -following <a href="#WINDOWS">sections</a></p> -<p>A Window is an imaginary screen defined by curses system. A -window does not mean a bordered window which you usually see on -Win9X platforms. When curses is initialized, it creates a default -window named <var class="LITERAL">stdscr</var> which represents -your 80x25 (or the size of window in which you are running) screen. -If you are doing simple tasks like printing few strings, reading -input etc., you can safely use this single window for all of your -purposes. You can also create windows and call functions which -explicitly work on the specified window.</p> -<p>For example, if you call</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> printw("Hi There !!!"); - refresh();</font> -</pre></td> -</tr> -</table> -<p>It prints the string on stdscr at the present cursor position. -Similarly the call to refresh(), works on stdscr only.</p> -<p>Say you have created <a href="#WINDOWS">windows</a> then you -have to call a function with a 'w' added to the usual function.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> wprintw(win, "Hi There !!!"); - wrefresh(win);</font> -</pre></td> -</tr> -</table> -<p>As you will see in the rest of the document, naming of functions -follow the same convention. For each function there usually are -three more functions.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> printw(string); /* Print on stdscr at present cursor position */ - mvprintw(y, x, string);/* Move to (y, x) then print string */ - wprintw(win, string); /* Print on window win at present cursor position */ - /* in the window */ - mvwprintw(win, y, x, string); /* Move to (y, x) relative to window */ - /* co-ordinates and then print */</font> -</pre></td> -</tr> -</table> -<p>Usually the w-less functions are macros which expand to -corresponding w-function with stdscr as the window parameter.</p> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="PRINTW" id="PRINTW">6. Output -functions</a></h2> -<p>I guess you can't wait any more to see some action. Back to our -odyssey of curses functions. Now that curses is initialized, let's -interact with world.</p> -<p>There are three classes of functions which you can use to do -output on screen.</p> -<ol type="1"> -<li> -<p>addch() class: Print single character with attributes</p> -</li> -<li> -<p>printw() class: Print formatted output similar to printf()</p> -</li> -<li> -<p>addstr() class: Print strings</p> -</li> -</ol> -<p>These functions can be used interchangeably and it's a matter of -style as to which class is used. Let's see each one in detail.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ADDCHCLASS" id="ADDCHCLASS">6.1. addch() -class of functions</a></h3> -<p>These functions put a single character into the current cursor -location and advance the position of the cursor. You can give the -character to be printed but they usually are used to print a -character with some attributes. Attributes are explained in detail -in later <a href="#ATTRIB">sections</a> of the document. If a -character is associated with an attribute(bold, reverse video -etc.), when curses prints the character, it is printed in that -attribute.</p> -<p>In order to combine a character with some attributes, you have -two options:</p> -<ul> -<li> -<p>By OR'ing a single character with the desired attribute macros. -These attribute macros could be found in the header file -<var class="LITERAL">ncurses.h</var>. For example, you want to -print a character ch(of type char) bold and underlined, you would -call addch() as below.</p> -<table border="0" bgcolor="#E0E0E0" width="90%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> addch(ch | A_BOLD | A_UNDERLINE);</font> -</pre></td> -</tr> -</table> -</li> -<li> -<p>By using functions like <var class= -"LITERAL">attrset(),attron(),attroff()</var>. These functions are -explained in the <a href="#ATTRIB">Attributes</a> section. Briefly, -they manipulate the current attributes of the given window. Once -set, the character printed in the window are associated with the -attributes until it is turned off.</p> -</li> -</ul> -<p>Additionally, <var class="LITERAL">curses</var> provides some -special characters for character-based graphics. You can draw -tables, horizontal or vertical lines, etc. You can find all -avaliable characters in the header file <var class= -"LITERAL">ncurses.h</var>. Try looking for macros beginning with -<var class="LITERAL">ACS_</var> in this file.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="AEN298" id="AEN298">6.2. mvaddch(), -waddch() and mvwaddch()</a></h3> -<p><var class="LITERAL">mvaddch()</var> is used to move the cursor -to a given point, and then print. Thus, the calls:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> move(row,col); /* moves the cursor to row<em>th</em> row and col<em>th</em> column */ - addch(ch);</font> -</pre></td> -</tr> -</table> -can be replaced by -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> mvaddch(row,col,ch);</font> -</pre></td> -</tr> -</table> -<p><var class="LITERAL">waddch()</var> is similar to <var class= -"LITERAL">addch()</var>, except that it adds a character into the -given window. (Note that <var class="LITERAL">addch()</var> adds a -character into the window <var class="LITERAL">stdscr</var>.)</p> -<p>In a similar fashion <var class="LITERAL">mvwaddch()</var> -function is used to add a character into the given window at the -given coordinates.</p> -<p>Now, we are familiar with the basic output function <var class= -"LITERAL">addch()</var>. But, if we want to print a string, it -would be very annoying to print it character by character. -Fortunately, <var class="LITERAL">ncurses</var> provides -<var class="LITERAL">printf</var><em>-like</em> or <var class= -"LITERAL">puts</var><em>-like</em> functions.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PRINTWCLASS" id="PRINTWCLASS">6.3. -printw() class of functions</a></h3> -<p>These functions are similar to <var class= -"LITERAL">printf()</var> with the added capability of printing at -any position on the screen.</p> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="PRINTWMVPRINTW" id= -"PRINTWMVPRINTW">6.3.1. printw() and mvprintw</a></h4> -<p>These two functions work much like <var class= -"LITERAL">printf()</var>. <var class="LITERAL">mvprintw()</var> can -be used to move the cursor to a position and then print. If you -want to move the cursor first and then print using <var class= -"LITERAL">printw()</var> function, use <var class= -"LITERAL">move()</var> first and then use <var class= -"LITERAL">printw()</var> though I see no point why one should avoid -using <var class="LITERAL">mvprintw()</var>, you have the -flexibility to manipulate.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="WPRINTWMVWPRINTW" id= -"WPRINTWMVWPRINTW">6.3.2. wprintw() and mvwprintw</a></h4> -<p>These two functions are similar to above two except that they -print in the corresponding window given as argument.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="VWPRINTW" id="VWPRINTW">6.3.3. -vwprintw()</a></h4> -<p>This function is similar to <var class= -"LITERAL">vprintf()</var>. This can be used when variable number of -arguments are to be printed.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="SIMPLEPRINTWEX" id= -"SIMPLEPRINTWEX">6.3.4. A Simple printw example</a></h4> -<div class="EXAMPLE"><a name="BPREX" id="BPREX"></a> -<p><b>Example 3. A Simple printw example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> /* ncurses.h includes stdio.h */ -#include <string.h> - -int main() -{ - char mesg[]="Just a string"; /* message to be appeared on the screen */ - int row,col; /* to store the number of rows and * - * the number of colums of the screen */ - initscr(); /* start the curses mode */ - getmaxyx(stdscr,row,col); /* get the number of rows and columns */ - mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg); - /* print the message at the center of the screen */ - mvprintw(row-2,0,"This screen has %d rows and %d columns\n",row,col); - printw("Try resizing your window(if possible) and then run this program again"); - refresh(); - getch(); - endwin(); - - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>Above program demonstrates how easy it is to use <var class= -"LITERAL">printw</var>. You just feed the coordinates and the -message to be appeared on the screen, then it does what you -want.</p> -<p>The above program introduces us to a new function <var class= -"LITERAL">getmaxyx()</var>, a macro defined in <var class= -"LITERAL">ncurses.h</var>. It gives the number of columns and the -number of rows in a given window. <var class= -"LITERAL">getmaxyx()</var> does this by updating the variables -given to it. Since <var class="LITERAL">getmaxyx()</var> is not a -function we don't pass pointers to it, we just give two integer -variables.</p> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ADDSTRCLASS" id="ADDSTRCLASS">6.4. -addstr() class of functions</a></h3> -<p><var class="LITERAL">addstr()</var> is used to put a character -string into a given window. This function is similar to calling -<var class="LITERAL">addch()</var> once for each character in a -given string. This is true for all output functions. There are -other functions from this family such as <var class= -"LITERAL">mvaddstr(),mvwaddstr()</var> and <var class= -"LITERAL">waddstr()</var>, which obey the naming convention of -curses.(e.g. mvaddstr() is similar to the respective calls move() -and then addstr().) Another function of this family is addnstr(), -which takes an integer parameter(say n) additionally. This function -puts at most n characters into the screen. If n is negative, then -the entire string will be added.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ACAUTION" id="ACAUTION">6.5. A word of -caution</a></h3> -<p>All these functions take y co-ordinate first and then x in their -arguments. A common mistake by beginners is to pass x,y in that -order. If you are doing too many manipulations of (y,x) -co-ordinates, think of dividing the screen into windows and -manipulate each one separately. Windows are explained in the -<a href="#WINDOWS">windows</a> section.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="SCANW" id="SCANW">7. Input -functions</a></h2> -<p>Well, printing without taking input, is boring. Let's see -functions which allow us to get input from user. These functions -also can be divided into three categories.</p> -<ol type="1"> -<li> -<p>getch() class: Get a character</p> -</li> -<li> -<p>scanw() class: Get formatted input</p> -</li> -<li> -<p>getstr() class: Get strings</p> -</li> -</ol> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="GETCHCLASS" id="GETCHCLASS">7.1. getch() -class of functions</a></h3> -<p>These functions read a single character from the terminal. But -there are several subtle facts to consider. For example if you -don't use the function cbreak(), curses will not read your input -characters contiguously but will begin read them only after a new -line or an EOF is encountered. In order to avoid this, the cbreak() -function must used so that characters are immediately available to -your program. Another widely used function is noecho(). As the name -suggests, when this function is set (used), the characters that are -keyed in by the user will not show up on the screen. The two -functions cbreak() and noecho() are typical examples of key -management. Functions of this genre are explained in the <a href= -"#KEYS">key management section</a> .</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="SCANWCLASS" id="SCANWCLASS">7.2. scanw() -class of functions</a></h3> -<p>These functions are similar to <var class= -"LITERAL">scanf()</var> with the added capability of getting the -input from any location on the screen.</p> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="SCANWMVSCANW" id="SCANWMVSCANW">7.2.1. -scanw() and mvscanw</a></h4> -<p>The usage of these functions is similar to that of <var class= -"LITERAL">sscanf()</var>, where the line to be scanned is provided -by <var class="LITERAL">wgetstr()</var> function. That is, these -functions call to <var class="LITERAL">wgetstr()</var> -function(explained below) and uses the resulting line for a -scan.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="WSCANWMVWSCANW" id= -"WSCANWMVWSCANW">7.2.2. wscanw() and mvwscanw()</a></h4> -<p>These are similar to above two functions except that they read -from a window, which is supplied as one of the arguments to these -functions.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="VWSCANW" id="VWSCANW">7.2.3. -vwscanw()</a></h4> -<p>This function is similar to <var class="LITERAL">vscanf()</var>. -This can be used when a variable number of arguments are to be -scanned.</p> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="GETSTRCLASS" id="GETSTRCLASS">7.3. -getstr() class of functions</a></h3> -<p>These functions are used to get strings from the terminal. In -essence, this function performs the same task as would be achieved -by a series of calls to <var class="LITERAL">getch()</var> until a -newline, carriage return, or end-of-file is received. The resulting -string of characters are pointed to by <var class= -"LITERAL">str</var>, which is a character pointer provided by the -user.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="GETSTREX" id="GETSTREX">7.4. Some -examples</a></h3> -<div class="EXAMPLE"><a name="BSCEX" id="BSCEX"></a> -<p><b>Example 4. A Simple scanw example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> /* ncurses.h includes stdio.h */ -#include <string.h> - -int main() -{ - char mesg[]="Enter a string: "; /* message to be appeared on the screen */ - char str[80]; - int row,col; /* to store the number of rows and * - * the number of colums of the screen */ - initscr(); /* start the curses mode */ - getmaxyx(stdscr,row,col); /* get the number of rows and columns */ - mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg); - /* print the message at the center of the screen */ - getstr(str); - mvprintw(LINES - 2, 0, "You Entered: %s", str); - getch(); - endwin(); - - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="ATTRIB" id="ATTRIB">8. -Attributes</a></h2> -<p>We have seen an example of how attributes can be used to print -characters with some special effects. Attributes, when set -prudently, can present information in an easy, understandable -manner. The following program takes a C file as input and prints -the file with comments in bold. Scan through the code.</p> -<div class="EXAMPLE"><a name="BSIAT" id="BSIAT"></a> -<p><b>Example 5. A Simple Attributes example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">/* pager functionality by Joseph Spainhour" <spainhou@bellsouth.net> */ -#include <ncurses.h> -#include <stdlib.h> - -int main(int argc, char *argv[]) -{ - int ch, prev, row, col; - prev = EOF; - FILE *fp; - int y, x; - - if(argc != 2) - { - printf("Usage: %s <a c file name>\n", argv[0]); - exit(1); - } - fp = fopen(argv[1], "r"); - if(fp == NULL) - { - perror("Cannot open input file"); - exit(1); - } - initscr(); /* Start curses mode */ - getmaxyx(stdscr, row, col); /* find the boundaries of the screeen */ - while((ch = fgetc(fp)) != EOF) /* read the file till we reach the end */ - { - getyx(stdscr, y, x); /* get the current curser position */ - if(y == (row - 1)) /* are we are at the end of the screen */ - { - printw("<-Press Any Key->"); /* tell the user to press a key */ - getch(); - clear(); /* clear the screen */ - move(0, 0); /* start at the beginning of the screen */ - } - if(prev == '/' && ch == '*') /* If it is / and * then only - * switch bold on */ - { - attron(A_BOLD); /* cut bold on */ - getyx(stdscr, y, x); /* get the current curser position */ - move(y, x - 1); /* back up one space */ - printw("%c%c", '/', ch); /* The actual printing is done here */ - } - else - printw("%c", ch); - refresh(); - if(prev == '*' && ch == '/') - attroff(A_BOLD); /* Switch it off once we got * - * and then / */ - prev = ch; - } - endwin(); /* End curses mode */ - fclose(fp); - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>Don't worry about all those initialization and other crap. -Concentrate on the while loop. It reads each character in the file -and searches for the pattern /*. Once it spots the pattern, it -switches the BOLD attribute on with <var class= -"LITERAL">attron()</var> . When we get the pattern */ it is -switched off by <var class="LITERAL">attroff()</var> .</p> -<p>The above program also introduces us to two useful functions -<var class="LITERAL">getyx()</var> and <var class= -"LITERAL">move()</var>. The first function gets the co-ordinates of -the present cursor into the variables y, x. Since getyx() is a -macro we don't have to pass pointers to variables. The function -<var class="LITERAL">move()</var> moves the cursor to the -co-ordinates given to it.</p> -<p>The above program is really a simple one which doesn't do much. -On these lines one could write a more useful program which reads a -C file, parses it and prints it in different colors. One could even -extend it to other languages as well.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ATTRIBDETAILS" id="ATTRIBDETAILS">8.1. -The details</a></h3> -<p>Let's get into more details of attributes. The functions -<var class="LITERAL">attron(), attroff(), attrset()</var> , and -their sister functions <var class="LITERAL">attr_get()</var> etc.. -can be used to switch attributes on/off , get attributes and -produce a colorful display.</p> -<p>The functions attron and attroff take a bit-mask of attributes -and switch them on or off, respectively. The following video -attributes, which are defined in <curses.h> can be passed to -these functions.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> - A_NORMAL Normal display (no highlight) - A_STANDOUT Best highlighting mode of the terminal. - A_UNDERLINE Underlining - A_REVERSE Reverse video - A_BLINK Blinking - A_DIM Half bright - A_BOLD Extra bright or bold - A_PROTECT Protected mode - A_INVIS Invisible or blank mode - A_ALTCHARSET Alternate character set - A_CHARTEXT Bit-mask to extract a character - COLOR_PAIR(n) Color-pair number n - </font> -</pre></td> -</tr> -</table> -<p>The last one is the most colorful one :-) Colors are explained -in the <a href="#color" target="_top">next sections</a>.</p> -<p>We can OR(|) any number of above attributes to get a combined -effect. If you wanted reverse video with blinking characters you -can use</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> attron(A_REVERSE | A_BLINK);</font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ATTRONVSATTRSET" id= -"ATTRONVSATTRSET">8.2. attron() vs attrset()</a></h3> -<p>Then what is the difference between attron() and attrset()? -attrset sets the attributes of window whereas attron just switches -on the attribute given to it. So attrset() fully overrides whatever -attributes the window previously had and sets it to the new -attribute(s). Similarly attroff() just switches off the -attribute(s) given to it as an argument. This gives us the -flexibility of managing attributes easily.But if you use them -carelessly you may loose track of what attributes the window has -and garble the display. This is especially true while managing -menus with colors and highlighting. So decide on a consistent -policy and stick to it. You can always use <var class= -"LITERAL">standend()</var> which is equivalent to <var class= -"LITERAL">attrset(A_NORMAL)</var> which turns off all attributes -and brings you to normal mode.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ATTR_GET" id="ATTR_GET">8.3. -attr_get()</a></h3> -<p>The function attr_get() gets the current attributes and color -pair of the window. Though we might not use this as often as the -above functions, this is useful in scanning areas of screen. Say we -wanted to do some complex update on screen and we are not sure what -attribute each character is associated with. Then this function can -be used with either attrset or attron to produce the desired -effect.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ATTR_FUNCS" id="ATTR_FUNCS">8.4. attr_ -functions</a></h3> -<p>There are series of functions like attr_set(), attr_on etc.. -These are similar to above functions except that they take -parameters of type <var class="LITERAL">attr_t</var>.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="WATTRFUNCS" id="WATTRFUNCS">8.5. wattr -functions</a></h3> -<p>For each of the above functions we have a corresponding function -with 'w' which operates on a particular window. The above functions -operate on stdscr.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="CHGAT" id="CHGAT">8.6. chgat() -functions</a></h3> -<p>The function chgat() is listed in the end of the man page -curs_attr. It actually is a useful one. This function can be used -to set attributes for a group of characters without moving. I mean -it !!! without moving the cursor :-) It changes the attributes of a -given number of characters starting at the current cursor -location.</p> -<p>We can give -1 as the character count to update till end of -line. If you want to change attributes of characters from current -position to end of line, just use this.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> chgat(-1, A_REVERSE, 0, NULL);</font> -</pre></td> -</tr> -</table> -<p>This function is useful when changing attributes for characters -that are already on the screen. Move to the character from which -you want to change and change the attribute.</p> -<p>Other functions wchgat(), mvchgat(), wchgat() behave similarly -except that the w functions operate on the particular window. The -mv functions first move the cursor then perform the work given to -them. Actually chgat is a macro which is replaced by a wchgat() -with stdscr as the window. Most of the "w-less" functions are -macros.</p> -<div class="EXAMPLE"><a name="BWICH" id="BWICH"></a> -<p><b>Example 6. Chgat() Usage example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - -int main(int argc, char *argv[]) -{ initscr(); /* Start curses mode */ - start_color(); /* Start color functionality */ - - init_pair(1, COLOR_CYAN, COLOR_BLACK); - printw("A Big string which i didn't care to type fully "); - mvchgat(0, 0, -1, A_BLINK, 1, NULL); - /* - * First two parameters specify the position at which to start - * Third parameter number of characters to update. -1 means till - * end of line - * Forth parameter is the normal attribute you wanted to give - * to the charcter - * Fifth is the color index. It is the index given during init_pair() - * use 0 if you didn't want color - * Sixth one is always NULL - */ - refresh(); - getch(); - endwin(); /* End curses mode */ - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>This example also introduces us to the color world of curses. -Colors will be explained in detail later. Use 0 for no color.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="WINDOWS" id="WINDOWS">9. -Windows</a></h2> -<p>Windows form the most important concept in curses. You have seen -the standard window stdscr above where all the functions implicitly -operated on this window. Now to make design even a simplest GUI, -you need to resort to windows. The main reason you may want to use -windows is to manipulate parts of the screen separately, for better -efficiency, by updating only the windows that need to be changed -and for a better design. I would say the last reason is the most -important in going for windows. You should always strive for a -better and easy-to-manage design in your programs. If you are -writing big, complex GUIs this is of pivotal importance before you -start doing anything.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="WINDOWBASICS" id="WINDOWBASICS">9.1. The -basics</a></h3> -<p>A Window can be created by calling the function <var class= -"LITERAL">newwin()</var>. It doesn't create any thing on the screen -actually. It allocates memory for a structure to manipulate the -window and updates the structure with data regarding the window -like it's size, beginy, beginx etc.. Hence in curses, a window is -just an abstraction of an imaginary window, which can be -manipulated independent of other parts of screen. The function -newwin() returns a pointer to structure WINDOW, which can be passed -to window related functions like wprintw() etc.. Finally the window -can be destroyed with delwin(). It will deallocate the memory -associated with the window structure.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="LETBEWINDOW" id="LETBEWINDOW">9.2. Let -there be a Window !!!</a></h3> -<p>What fun is it, if a window is created and we can't see it. So -the fun part begins by displaying the window. The function -<var class="LITERAL">box()</var> can be used to draw a border -around the window. Let's explore these functions in more detail in -this example.</p> -<div class="EXAMPLE"><a name="BWIBO" id="BWIBO"></a> -<p><b>Example 7. Window Border example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - - -WINDOW *create_newwin(int height, int width, int starty, int startx); -void destroy_win(WINDOW *local_win); - -int main(int argc, char *argv[]) -{ WINDOW *my_win; - int startx, starty, width, height; - int ch; - - initscr(); /* Start curses mode */ - cbreak(); /* Line buffering disabled, Pass on - * everty thing to me */ - keypad(stdscr, TRUE); /* I need that nifty F1 */ - - height = 3; - width = 10; - starty = (LINES - height) / 2; /* Calculating for a center placement */ - startx = (COLS - width) / 2; /* of the window */ - printw("Press F1 to exit"); - refresh(); - my_win = create_newwin(height, width, starty, startx); - - while((ch = getch()) != KEY_F(1)) - { switch(ch) - { case KEY_LEFT: - destroy_win(my_win); - my_win = create_newwin(height, width, starty,--startx); - break; - case KEY_RIGHT: - destroy_win(my_win); - my_win = create_newwin(height, width, starty,++startx); - break; - case KEY_UP: - destroy_win(my_win); - my_win = create_newwin(height, width, --starty,startx); - break; - case KEY_DOWN: - destroy_win(my_win); - my_win = create_newwin(height, width, ++starty,startx); - break; - } - } - - endwin(); /* End curses mode */ - return 0; -} - -WINDOW *create_newwin(int height, int width, int starty, int startx) -{ WINDOW *local_win; - - local_win = newwin(height, width, starty, startx); - box(local_win, 0 , 0); /* 0, 0 gives default characters - * for the vertical and horizontal - * lines */ - wrefresh(local_win); /* Show that box */ - - return local_win; -} - -void destroy_win(WINDOW *local_win) -{ - /* box(local_win, ' ', ' '); : This won't produce the desired - * result of erasing the window. It will leave it's four corners - * and so an ugly remnant of window. - */ - wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' '); - /* The parameters taken are - * 1. win: the window on which to operate - * 2. ls: character to be used for the left side of the window - * 3. rs: character to be used for the right side of the window - * 4. ts: character to be used for the top side of the window - * 5. bs: character to be used for the bottom side of the window - * 6. tl: character to be used for the top left corner of the window - * 7. tr: character to be used for the top right corner of the window - * 8. bl: character to be used for the bottom left corner of the window - * 9. br: character to be used for the bottom right corner of the window - */ - wrefresh(local_win); - delwin(local_win); -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="BORDEREXEXPL" id="BORDEREXEXPL">9.3. -Explanation</a></h3> -<p>Don't scream. I know it's a big example. But I have to explain -some important things here :-). This program creates a rectangular -window that can be moved with left, right, up, down arrow keys. It -repeatedly creates and destroys windows as user press a key. Don't -go beyond the screen limits. Checking for those limits is left as -an exercise for the reader. Let's dissect it by line by line.</p> -<p>The <var class="LITERAL">create_newwin()</var> function creates -a window with <var class="LITERAL">newwin()</var> and displays a -border around it with box. The function <var class= -"LITERAL">destroy_win()</var> first erases the window from screen -by painting a border with ' ' character and then calling -<var class="LITERAL">delwin()</var> to deallocate memory related to -it. Depending on the key the user presses, starty or startx is -changed and a new window is created.</p> -<p>In the destroy_win, as you can see, I used wborder instead of -box. The reason is written in the comments (You missed it. I know. -Read the code :-)). wborder draws a border around the window with -the characters given to it as the 4 corner points and the 4 lines. -To put it clearly, if you have called wborder as below:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> wborder(win, '|', '|', '-', '-', '+', '+', '+', '+');</font> -</pre></td> -</tr> -</table> -<p>it produces some thing like</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> +------------+ - | | - | | - | | - | | - | | - | | - +------------+</font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="OTHERSTUFF" id="OTHERSTUFF">9.4. The -other stuff in the example</a></h3> -<p>You can also see in the above examples, that I have used the -variables COLS, LINES which are initialized to the screen sizes -after initscr(). They can be useful in finding screen dimensions -and finding the center co-ordinate of the screen as above. The -function <var class="LITERAL">getch()</var> as usual gets the key -from keyboard and according to the key it does the corresponding -work. This type of switch- case is very common in any GUI based -programs.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="OTHERBORDERFUNCS" id= -"OTHERBORDERFUNCS">9.5. Other Border functions</a></h3> -<p>Above program is grossly inefficient in that with each press of -a key, a window is destroyed and another is created. So let's write -a more efficient program which uses other border related -functions.</p> -<p>The following program uses <var class="LITERAL">mvhline()</var> -and <var class="LITERAL">mvvline()</var> to achieve similar effect. -These two functions are simple. They create a horizontal or -vertical line of the specified length at the specified -position.</p> -<div class="EXAMPLE"><a name="BOTBO" id="BOTBO"></a> -<p><b>Example 8. More border functions</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - -typedef struct _win_border_struct { - chtype ls, rs, ts, bs, - tl, tr, bl, br; -}WIN_BORDER; - -typedef struct _WIN_struct { - - int startx, starty; - int height, width; - WIN_BORDER border; -}WIN; - -void init_win_params(WIN *p_win); -void print_win_params(WIN *p_win); -void create_box(WIN *win, bool flag); - -int main(int argc, char *argv[]) -{ WIN win; - int ch; - - initscr(); /* Start curses mode */ - start_color(); /* Start the color functionality */ - cbreak(); /* Line buffering disabled, Pass on - * everty thing to me */ - keypad(stdscr, TRUE); /* I need that nifty F1 */ - noecho(); - init_pair(1, COLOR_CYAN, COLOR_BLACK); - - /* Initialize the window parameters */ - init_win_params(&win); - print_win_params(&win); - - attron(COLOR_PAIR(1)); - printw("Press F1 to exit"); - refresh(); - attroff(COLOR_PAIR(1)); - - create_box(&win, TRUE); - while((ch = getch()) != KEY_F(1)) - { switch(ch) - { case KEY_LEFT: - create_box(&win, FALSE); - --win.startx; - create_box(&win, TRUE); - break; - case KEY_RIGHT: - create_box(&win, FALSE); - ++win.startx; - create_box(&win, TRUE); - break; - case KEY_UP: - create_box(&win, FALSE); - --win.starty; - create_box(&win, TRUE); - break; - case KEY_DOWN: - create_box(&win, FALSE); - ++win.starty; - create_box(&win, TRUE); - break; - } - } - endwin(); /* End curses mode */ - return 0; -} -void init_win_params(WIN *p_win) -{ - p_win->height = 3; - p_win->width = 10; - p_win->starty = (LINES - p_win->height)/2; - p_win->startx = (COLS - p_win->width)/2; - - p_win->border.ls = '|'; - p_win->border.rs = '|'; - p_win->border.ts = '-'; - p_win->border.bs = '-'; - p_win->border.tl = '+'; - p_win->border.tr = '+'; - p_win->border.bl = '+'; - p_win->border.br = '+'; - -} -void print_win_params(WIN *p_win) -{ -#ifdef _DEBUG - mvprintw(25, 0, "%d %d %d %d", p_win->startx, p_win->starty, - p_win->width, p_win->height); - refresh(); -#endif -} -void create_box(WIN *p_win, bool flag) -{ int i, j; - int x, y, w, h; - - x = p_win->startx; - y = p_win->starty; - w = p_win->width; - h = p_win->height; - - if(flag == TRUE) - { mvaddch(y, x, p_win->border.tl); - mvaddch(y, x + w, p_win->border.tr); - mvaddch(y + h, x, p_win->border.bl); - mvaddch(y + h, x + w, p_win->border.br); - mvhline(y, x + 1, p_win->border.ts, w - 1); - mvhline(y + h, x + 1, p_win->border.bs, w - 1); - mvvline(y + 1, x, p_win->border.ls, h - 1); - mvvline(y + 1, x + w, p_win->border.rs, h - 1); - - } - else - for(j = y; j <= y + h; ++j) - for(i = x; i <= x + w; ++i) - mvaddch(j, i, ' '); - - refresh(); - -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="COLOR" id="COLOR">10. Colors</a></h2> -<div class="SECT2"> -<h3 class="SECT2"><a name="COLORBASICS" id="COLORBASICS">10.1. The -basics</a></h3> -<p>Life seems dull with no colors. Curses has a nice mechanism to -handle colors. Let's get into the thick of the things with a small -program.</p> -<div class="EXAMPLE"><a name="BSICO" id="BSICO"></a> -<p><b>Example 9. A Simple Color example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string); -int main(int argc, char *argv[]) -{ initscr(); /* Start curses mode */ - if(has_colors() == FALSE) - { endwin(); - printf("Your terminal does not support color\n"); - exit(1); - } - start_color(); /* Start color */ - init_pair(1, COLOR_RED, COLOR_BLACK); - - attron(COLOR_PAIR(1)); - print_in_middle(stdscr, LINES / 2, 0, 0, "Viola !!! In color ..."); - attroff(COLOR_PAIR(1)); - getch(); - endwin(); -} -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string) -{ int length, x, y; - float temp; - - if(win == NULL) - win = stdscr; - getyx(win, y, x); - if(startx != 0) - x = startx; - if(starty != 0) - y = starty; - if(width == 0) - width = 80; - - length = strlen(string); - temp = (width - length)/ 2; - x = startx + (int)temp; - mvwprintw(win, y, x, "%s", string); - refresh(); -} -</span></font> -</pre></td> -</tr> -</table> -</div> -<p>As you can see, to start using color, you should first call the -function <var class="LITERAL">start_color()</var>. After that, you -can use color capabilities of your terminals using various -functions. To find out whether a terminal has color capabilities or -not, you can use <var class="LITERAL">has_colors()</var> function, -which returns FALSE if the terminal does not support color.</p> -<p>Curses initializes all the colors supported by terminal when -start_color() is called. These can be accessed by the define -constants like <var class="LITERAL">COLOR_BLACK</var> etc. Now to -actually start using colors, you have to define pairs. Colors are -always used in pairs. That means you have to use the function -<var class="LITERAL">init_pair()</var> to define the foreground and -background for the pair number you give. After that that pair -number can be used as a normal attribute with <var class= -"LITERAL">COLOR_PAIR()</var>function. This may seem to be -cumbersome at first. But this elegant solution allows us to manage -color pairs very easily. To appreciate it, you have to look into -the the source code of "dialog", a utility for displaying dialog -boxes from shell scripts. The developers have defined foreground -and background combinations for all the colors they might need and -initialized at the beginning. This makes it very easy to set -attributes just by accessing a pair which we already have defined -as a constant.</p> -<p>The following colors are defined in <var class= -"LITERAL">curses.h</var>. You can use these as parameters for -various color functions.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> COLOR_BLACK 0 - COLOR_RED 1 - COLOR_GREEN 2 - COLOR_YELLOW 3 - COLOR_BLUE 4 - COLOR_MAGENTA 5 - COLOR_CYAN 6 - COLOR_WHITE 7</font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="CHANGECOLORDEFS" id= -"CHANGECOLORDEFS">10.2. Changing Color Definitions</a></h3> -<p>The function <var class="LITERAL">init_color()</var>can be used -to change the rgb values for the colors defined by curses -initially. Say you wanted to lighten the intensity of red color by -a minuscule. Then you can use this function as</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> init_color(COLOR_RED, 700, 0, 0); - /* param 1 : color name - * param 2, 3, 4 : rgb content min = 0, max = 1000 */</font> -</pre></td> -</tr> -</table> -<p>If your terminal cannot change the color definitions, the -function returns ERR. The function <var class= -"LITERAL">can_change_color()</var> can be used to find out whether -the terminal has the capability of changing color content or not. -The rgb content is scaled from 0 to 1000. Initially RED color is -defined with content 1000(r), 0(g), 0(b).</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="COLORCONTENT" id="COLORCONTENT">10.3. -Color Content</a></h3> -<p>The functions <var class="LITERAL">color_content()</var> and -<var class="LITERAL">pair_content()</var> can be used to find the -color content and foreground, background combination for the -pair.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="KEYS" id="KEYS">11. Interfacing with the -key board</a></h2> -<div class="SECT2"> -<h3 class="SECT2"><a name="KEYSBASICS" id="KEYSBASICS">11.1. The -Basics</a></h3> -<p>No GUI is complete without a strong user interface and to -interact with the user, a curses program should be sensitive to key -presses or the mouse actions done by the user. Let's deal with the -keys first.</p> -<p>As you have seen in almost all of the above examples, it's very -easy to get key input from the user. A simple way of getting key -presses is to use <var class="LITERAL">getch()</var> function. The -cbreak mode should be enabled to read keys when you are interested -in reading individual key hits rather than complete lines of text -(which usually end with a carriage return). keypad should be -enabled to get the Functions keys, arrow keys etc. See the -initialization section for details.</p> -<p><var class="LITERAL">getch()</var> returns an integer -corresponding to the key pressed. If it is a normal character, the -integer value will be equivalent to the character. Otherwise it -returns a number which can be matched with the constants defined in -<var class="LITERAL">curses.h</var>. For example if the user -presses F1, the integer returned is 265. This can be checked using -the macro KEY_F() defined in curses.h. This makes reading keys -portable and easy to manage.</p> -<p>For example, if you call getch() like this</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> int ch; - - ch = getch();</font> -</pre></td> -</tr> -</table> -<p>getch() will wait for the user to press a key, (unless you -specified a timeout) and when user presses a key, the corresponding -integer is returned. Then you can check the value returned with the -constants defined in curses.h to match against the keys you -want.</p> -<p>The following code piece will do that job.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> if(ch == KEY_LEFT) - printw("Left arrow is pressed\n");</font> -</pre></td> -</tr> -</table> -<p>Let's write a small program which creates a menu which can be -navigated by up and down arrows.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="SIMPLEKEYEX" id="SIMPLEKEYEX">11.2. A -Simple Key Usage example</a></h3> -<div class="EXAMPLE"><a name="BSIKE" id="BSIKE"></a> -<p><b>Example 10. A Simple Key Usage example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <stdio.h> -#include <ncurses.h> - -#define WIDTH 30 -#define HEIGHT 10 - -int startx = 0; -int starty = 0; - -char *choices[] = { - "Choice 1", - "Choice 2", - "Choice 3", - "Choice 4", - "Exit", - }; -int n_choices = sizeof(choices) / sizeof(char *); -void print_menu(WINDOW *menu_win, int highlight); - -int main() -{ WINDOW *menu_win; - int highlight = 1; - int choice = 0; - int c; - - initscr(); - clear(); - noecho(); - cbreak(); /* Line buffering disabled. pass on everything */ - startx = (80 - WIDTH) / 2; - starty = (24 - HEIGHT) / 2; - - menu_win = newwin(HEIGHT, WIDTH, starty, startx); - keypad(menu_win, TRUE); - mvprintw(0, 0, "Use arrow keys to go up and down, Press enter to select a choice"); - refresh(); - print_menu(menu_win, highlight); - while(1) - { c = wgetch(menu_win); - switch(c) - { case KEY_UP: - if(highlight == 1) - highlight = n_choices; - else - --highlight; - break; - case KEY_DOWN: - if(highlight == n_choices) - highlight = 1; - else - ++highlight; - break; - case 10: - choice = highlight; - break; - default: - mvprintw(24, 0, "Charcter pressed is = %3d Hopefully it can be printed as '%c'", c, c); - refresh(); - break; - } - print_menu(menu_win, highlight); - if(choice != 0) /* User did a choice come out of the infinite loop */ - break; - } - mvprintw(23, 0, "You chose choice %d with choice string %s\n", choice, choices[choice - 1]); - clrtoeol(); - refresh(); - endwin(); - return 0; -} - - -void print_menu(WINDOW *menu_win, int highlight) -{ - int x, y, i; - - x = 2; - y = 2; - box(menu_win, 0, 0); - for(i = 0; i < n_choices; ++i) - { if(highlight == i + 1) /* High light the present choice */ - { wattron(menu_win, A_REVERSE); - mvwprintw(menu_win, y, x, "%s", choices[i]); - wattroff(menu_win, A_REVERSE); - } - else - mvwprintw(menu_win, y, x, "%s", choices[i]); - ++y; - } - wrefresh(menu_win); -} -</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="MOUSE" id="MOUSE">12. Interfacing with -the mouse</a></h2> -<p>Now that you have seen how to get keys, lets do the same thing -from mouse. Usually each UI allows the user to interact with both -keyboard and mouse.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MOUSEBASICS" id="MOUSEBASICS">12.1. The -Basics</a></h3> -<p>Before you do any thing else, the events you want to receive -have to be enabled with <var class="LITERAL">mousemask()</var>.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> mousemask( mmask_t newmask, /* The events you want to listen to */ - mmask_t *oldmask) /* The old events mask */</font> -</pre></td> -</tr> -</table> -<p>The first parameter to above function is a bit mask of events -you would like to listen. By default, all the events are turned -off. The bit mask <var class="LITERAL">ALL_MOUSE_EVENTS</var> can -be used to get all the events.</p> -<p>The following are all the event masks:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> Name Description - --------------------------------------------------------------------- - BUTTON1_PRESSED mouse button 1 down - BUTTON1_RELEASED mouse button 1 up - BUTTON1_CLICKED mouse button 1 clicked - BUTTON1_DOUBLE_CLICKED mouse button 1 double clicked - BUTTON1_TRIPLE_CLICKED mouse button 1 triple clicked - BUTTON2_PRESSED mouse button 2 down - BUTTON2_RELEASED mouse button 2 up - BUTTON2_CLICKED mouse button 2 clicked - BUTTON2_DOUBLE_CLICKED mouse button 2 double clicked - BUTTON2_TRIPLE_CLICKED mouse button 2 triple clicked - BUTTON3_PRESSED mouse button 3 down - BUTTON3_RELEASED mouse button 3 up - BUTTON3_CLICKED mouse button 3 clicked - BUTTON3_DOUBLE_CLICKED mouse button 3 double clicked - BUTTON3_TRIPLE_CLICKED mouse button 3 triple clicked - BUTTON4_PRESSED mouse button 4 down - BUTTON4_RELEASED mouse button 4 up - BUTTON4_CLICKED mouse button 4 clicked - BUTTON4_DOUBLE_CLICKED mouse button 4 double clicked - BUTTON4_TRIPLE_CLICKED mouse button 4 triple clicked - BUTTON_SHIFT shift was down during button state change - BUTTON_CTRL control was down during button state change - BUTTON_ALT alt was down during button state change - ALL_MOUSE_EVENTS report all button state changes - REPORT_MOUSE_POSITION report mouse movement</font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="GETTINGEVENTS" id="GETTINGEVENTS">12.2. -Getting the events</a></h3> -<p>Once a class of mouse events have been enabled, getch() class of -functions return KEY_MOUSE every time some mouse event happens. -Then the mouse event can be retrieved with <var class= -"LITERAL">getmouse()</var>.</p> -<p>The code approximately looks like this:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> MEVENT event; - - ch = getch(); - if(ch == KEY_MOUSE) - if(getmouse(&event) == OK) - . /* Do some thing with the event */ - . - .</font> -</pre></td> -</tr> -</table> -<p>getmouse() returns the event into the pointer given to it. It's -a structure which contains</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> typedef struct - { - short id; /* ID to distinguish multiple devices */ - int x, y, z; /* event coordinates */ - mmask_t bstate; /* button state bits */ - } </font> -</pre></td> -</tr> -</table> -<p>The <var class="LITERAL">bstate</var> is the main variable we -are interested in. It tells the button state of the mouse.</p> -<p>Then with a code snippet like the following, we can find out -what happened.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> if(event.bstate & BUTTON1_PRESSED) - printw("Left Button Pressed");</font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MOUSETOGETHER" id="MOUSETOGETHER">12.3. -Putting it all Together</a></h3> -<p>That's pretty much interfacing with mouse. Let's create the same -menu and enable mouse interaction. To make things simpler, key -handling is removed.</p> -<div class="EXAMPLE"><a name="BMOME" id="BMOME"></a> -<p><b>Example 11. Access the menu with mouse !!!</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - -#define WIDTH 30 -#define HEIGHT 10 - -int startx = 0; -int starty = 0; - -char *choices[] = { "Choice 1", - "Choice 2", - "Choice 3", - "Choice 4", - "Exit", - }; - -int n_choices = sizeof(choices) / sizeof(char *); - -void print_menu(WINDOW *menu_win, int highlight); -void report_choice(int mouse_x, int mouse_y, int *p_choice); - -int main() -{ int c, choice = 0; - WINDOW *menu_win; - MEVENT event; - - /* Initialize curses */ - initscr(); - clear(); - noecho(); - cbreak(); //Line buffering disabled. pass on everything - - /* Try to put the window in the middle of screen */ - startx = (80 - WIDTH) / 2; - starty = (24 - HEIGHT) / 2; - - attron(A_REVERSE); - mvprintw(23, 1, "Click on Exit to quit (Works best in a virtual console)"); - refresh(); - attroff(A_REVERSE); - - /* Print the menu for the first time */ - menu_win = newwin(HEIGHT, WIDTH, starty, startx); - print_menu(menu_win, 1); - /* Get all the mouse events */ - mousemask(ALL_MOUSE_EVENTS, NULL); - - while(1) - { c = wgetch(menu_win); - switch(c) - { case KEY_MOUSE: - if(getmouse(&event) == OK) - { /* When the user clicks left mouse button */ - if(event.bstate & BUTTON1_PRESSED) - { report_choice(event.x + 1, event.y + 1, &choice); - if(choice == -1) //Exit chosen - goto end; - mvprintw(22, 1, "Choice made is : %d String Chosen is \"%10s\"", choice, choices[choice - 1]); - refresh(); - } - } - print_menu(menu_win, choice); - break; - } - } -end: - endwin(); - return 0; -} - - -void print_menu(WINDOW *menu_win, int highlight) -{ - int x, y, i; - - x = 2; - y = 2; - box(menu_win, 0, 0); - for(i = 0; i < n_choices; ++i) - { if(highlight == i + 1) - { wattron(menu_win, A_REVERSE); - mvwprintw(menu_win, y, x, "%s", choices[i]); - wattroff(menu_win, A_REVERSE); - } - else - mvwprintw(menu_win, y, x, "%s", choices[i]); - ++y; - } - wrefresh(menu_win); -} - -/* Report the choice according to mouse position */ -void report_choice(int mouse_x, int mouse_y, int *p_choice) -{ int i,j, choice; - - i = startx + 2; - j = starty + 3; - - for(choice = 0; choice < n_choices; ++choice) - if(mouse_y == j + choice && mouse_x >= i && mouse_x <= i + strlen(choices[choice])) - { if(choice == n_choices - 1) - *p_choice = -1; - else - *p_choice = choice + 1; - break; - } -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MISCMOUSEFUNCS" id= -"MISCMOUSEFUNCS">12.4. Miscellaneous Functions</a></h3> -<p>The functions mouse_trafo() and wmouse_trafo() can be used to -convert to mouse co-ordinates to screen relative co-ordinates. See -curs_mouse(3X) man page for details.</p> -<p>The mouseinterval function sets the maximum time (in thousands -of a second) that can elapse between press and release events in -order for them to be recognized as a click. This function returns -the previous interval value. The default is one fifth of a -second.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="SCREEN" id="SCREEN">13. Screen -Manipulation</a></h2> -<p>In this section, we will look into some functions, which allow -us to manage the screen efficiently and to write some fancy -programs. This is especially important in writing games.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="GETYX" id="GETYX">13.1. getyx() -functions</a></h3> -<p>The function <var class="LITERAL">getyx()</var> can be used to -find out the present cursor co-ordinates. It will fill the values -of x and y co-ordinates in the arguments given to it. Since getyx() -is a macro you don't have to pass the address of the variables. It -can be called as</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> getyx(win, y, x); - /* win: window pointer - * y, x: y, x co-ordinates will be put into this variables - */</font> -</pre></td> -</tr> -</table> -<p>The function getparyx() gets the beginning co-ordinates of the -sub window relative to the main window. This is some times useful -to update a sub window. When designing fancy stuff like writing -multiple menus, it becomes difficult to store the menu positions, -their first option co-ordinates etc. A simple solution to this -problem, is to create menus in sub windows and later find the -starting co-ordinates of the menus by using getparyx().</p> -<p>The functions getbegyx() and getmaxyx() store current window's -beginning and maximum co-ordinates. These functions are useful in -the same way as above in managing the windows and sub windows -effectively.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="SCREENDUMP" id="SCREENDUMP">13.2. Screen -Dumping</a></h3> -<p>While writing games, some times it becomes necessary to store -the state of the screen and restore it back to the same state. The -function scr_dump() can be used to dump the screen contents to a -file given as an argument. Later it can be restored by scr_restore -function. These two simple functions can be used effectively to -maintain a fast moving game with changing scenarios.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="WINDOWDUMP" id="WINDOWDUMP">13.3. Window -Dumping</a></h3> -<p>To store and restore windows, the functions <var class= -"LITERAL">putwin()</var> and <var class="LITERAL">getwin()</var> -can be used. <var class="LITERAL">putwin()</var> puts the present -window state into a file, which can be later restored by -<var class="LITERAL">getwin()</var>.</p> -<p>The function <var class="LITERAL">copywin()</var> can be used to -copy a window completely onto another window. It takes the source -and destination windows as parameters and according to the -rectangle specified, it copies the rectangular region from source -to destination window. It's last parameter specifies whether to -overwrite or just overlay the contents on to the destination -window. If this argument is true, then the copying is -non-destructive.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="MISC" id="MISC">14. Miscellaneous -features</a></h2> -<p>Now you know enough features to write a good curses program, -with all bells and whistles. There are some miscellaneous functions -which are useful in various cases. Let's go headlong into some of -those.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="CURSSET" id="CURSSET">14.1. -curs_set()</a></h3> -<p>This function can be used to make the cursor invisible. The -parameter to this function should be</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> 0 : invisible or - 1 : normal or - 2 : very visible.</font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="TEMPLEAVE" id="TEMPLEAVE">14.2. -Temporarily Leaving Curses mode</a></h3> -<p>Some times you may want to get back to cooked mode (normal line -buffering mode) temporarily. In such a case you will first need to -save the tty modes with a call to <var class= -"LITERAL">def_prog_mode()</var> and then call <var class= -"LITERAL">endwin()</var> to end the curses mode. This will leave -you in the original tty mode. To get back to curses once you are -done, call <var class="LITERAL">reset_prog_mode()</var> . This -function returns the tty to the state stored by <var class= -"LITERAL">def_prog_mode()</var>. Then do refresh(), and you are -back to the curses mode. Here is an example showing the sequence of -things to be done.</p> -<div class="EXAMPLE"><a name="BTELE" id="BTELE"></a> -<p><b>Example 12. Temporarily Leaving Curses Mode</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - -int main() -{ - initscr(); /* Start curses mode */ - printw("Hello World !!!\n"); /* Print Hello World */ - refresh(); /* Print it on to the real screen */ - def_prog_mode(); /* Save the tty modes */ - endwin(); /* End curses mode temporarily */ - system("/bin/sh"); /* Do whatever you like in cooked mode */ - reset_prog_mode(); /* Return to the previous tty mode*/ - /* stored by def_prog_mode() */ - refresh(); /* Do refresh() to restore the */ - /* Screen contents */ - printw("Another String\n"); /* Back to curses use the full */ - refresh(); /* capabilities of curses */ - endwin(); /* End curses mode */ - - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="ACSVARS" id="ACSVARS">14.3. ACS_ -variables</a></h3> -<p>If you have ever programmed in DOS, you know about those nifty -characters in extended character set. They are printable only on -some terminals. NCURSES functions like <var class= -"LITERAL">box()</var> use these characters. All these variables -start with ACS meaning alternative character set. You might have -noticed me using these characters in some of the programs above. -Here's an example showing all the characters.</p> -<div class="EXAMPLE"><a name="BACSVARS" id="BACSVARS"></a> -<p><b>Example 13. ACS Variables Example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <ncurses.h> - -int main() -{ - initscr(); - - printw("Upper left corner "); addch(ACS_ULCORNER); printw("\n"); - printw("Lower left corner "); addch(ACS_LLCORNER); printw("\n"); - printw("Lower right corner "); addch(ACS_LRCORNER); printw("\n"); - printw("Tee pointing right "); addch(ACS_LTEE); printw("\n"); - printw("Tee pointing left "); addch(ACS_RTEE); printw("\n"); - printw("Tee pointing up "); addch(ACS_BTEE); printw("\n"); - printw("Tee pointing down "); addch(ACS_TTEE); printw("\n"); - printw("Horizontal line "); addch(ACS_HLINE); printw("\n"); - printw("Vertical line "); addch(ACS_VLINE); printw("\n"); - printw("Large Plus or cross over "); addch(ACS_PLUS); printw("\n"); - printw("Scan Line 1 "); addch(ACS_S1); printw("\n"); - printw("Scan Line 3 "); addch(ACS_S3); printw("\n"); - printw("Scan Line 7 "); addch(ACS_S7); printw("\n"); - printw("Scan Line 9 "); addch(ACS_S9); printw("\n"); - printw("Diamond "); addch(ACS_DIAMOND); printw("\n"); - printw("Checker board (stipple) "); addch(ACS_CKBOARD); printw("\n"); - printw("Degree Symbol "); addch(ACS_DEGREE); printw("\n"); - printw("Plus/Minus Symbol "); addch(ACS_PLMINUS); printw("\n"); - printw("Bullet "); addch(ACS_BULLET); printw("\n"); - printw("Arrow Pointing Left "); addch(ACS_LARROW); printw("\n"); - printw("Arrow Pointing Right "); addch(ACS_RARROW); printw("\n"); - printw("Arrow Pointing Down "); addch(ACS_DARROW); printw("\n"); - printw("Arrow Pointing Up "); addch(ACS_UARROW); printw("\n"); - printw("Board of squares "); addch(ACS_BOARD); printw("\n"); - printw("Lantern Symbol "); addch(ACS_LANTERN); printw("\n"); - printw("Solid Square Block "); addch(ACS_BLOCK); printw("\n"); - printw("Less/Equal sign "); addch(ACS_LEQUAL); printw("\n"); - printw("Greater/Equal sign "); addch(ACS_GEQUAL); printw("\n"); - printw("Pi "); addch(ACS_PI); printw("\n"); - printw("Not equal "); addch(ACS_NEQUAL); printw("\n"); - printw("UK pound sign "); addch(ACS_STERLING); printw("\n"); - - refresh(); - getch(); - endwin(); - - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="OTHERLIB" id="OTHERLIB">15. Other -libraries</a></h2> -<p>Apart from the curses library, there are few text mode -libraries, which provide more functionality and a lot of features. -The following sections explain three standard libraries which are -usually distributed along with curses.</p> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="PANELS" id="PANELS">16. Panel -Library</a></h2> -<p>Now that you are proficient in curses, you wanted to do some -thing big. You created a lot of overlapping windows to give a -professional windows-type look. Unfortunately, it soon becomes -difficult to manage these. The multiple refreshes, updates plunge -you into a nightmare. The overlapping windows create blotches, -whenever you forget to refresh the windows in the proper order.</p> -<p>Don't despair. There's an elegant solution provided in panels -library. In the words of developers of ncurses</p> -<p><em>When your interface design is such that windows may dive -deeper into the visibility stack or pop to the top at runtime, the -resulting book-keeping can be tedious and difficult to get right. -Hence the panels library.</em></p> -<p>If you have lot of overlapping windows, then panels library is -the way to go. It obviates the need of doing series of -wnoutrefresh(), doupdate() and relieves the burden of doing it -correctly(bottom up). The library maintains information about the -order of windows, their overlapping and update the screen properly. -So why wait? Let's take a close peek into panels.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PANELBASICS" id="PANELBASICS">16.1. The -Basics</a></h3> -<p>Panel object is a window that is implicitly treated as part of a -deck including all other panel objects. The deck is treated as a -stack with the top panel being completely visible and the other -panels may or may not be obscured according to their positions. So -the basic idea is to create a stack of overlapping panels and use -panels library to display them correctly. There is a function -similar to refresh() which, when called , displays panels in the -correct order. Functions are provided to hide or show panels, move -panels, change its size etc.. The overlapping problem is managed by -the panels library during all the calls to these functions.</p> -<p>The general flow of a panel program goes like this:</p> -<ol type="1"> -<li> -<p>Create the windows (with newwin()) to be attached to the -panels.</p> -</li> -<li> -<p>Create panels with the chosen visibility order. Stack them up -according to the desired visibility. The function new_panel() is -used to created panels.</p> -</li> -<li> -<p>Call update_panels() to write the panels to the virtual screen -in correct visibility order. Do a doupdate() to show it on the -screen.</p> -</li> -<li> -<p>Mainpulate the panels with show_panel(), hide_panel(), -move_panel() etc. Make use of helper functions like panel_hidden() -and panel_window(). Make use of user pointer to store custom data -for a panel. Use the functions set_panel_userptr() and -panel_userptr() to set and get the user pointer for a panel.</p> -</li> -<li> -<p>When you are done with the panel use del_panel() to delete the -panel.</p> -</li> -</ol> -<p>Let's make the concepts clear, with some programs. The following -is a simple program which creates 3 overlapping panels and shows -them on the screen.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="COMPILEPANELS" id="COMPILEPANELS">16.2. -Compiling With the Panels Library</a></h3> -<p>To use panels library functions, you have to include panel.h and -to link the program with panels library the flag -lpanel should be -added along with -lncurses in that order.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> #include <panel.h> - . - . - . - - compile and link: gcc <program file> -lpanel -lncurses</font> -</pre></td> -</tr> -</table> -<div class="EXAMPLE"><a name="PPASI" id="PPASI"></a> -<p><b>Example 14. Panel basics</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <panel.h> - -int main() -{ WINDOW *my_wins[3]; - PANEL *my_panels[3]; - int lines = 10, cols = 40, y = 2, x = 4, i; - - initscr(); - cbreak(); - noecho(); - - /* Create windows for the panels */ - my_wins[0] = newwin(lines, cols, y, x); - my_wins[1] = newwin(lines, cols, y + 1, x + 5); - my_wins[2] = newwin(lines, cols, y + 2, x + 10); - - /* - * Create borders around the windows so that you can see the effect - * of panels - */ - for(i = 0; i < 3; ++i) - box(my_wins[i], 0, 0); - - /* Attach a panel to each window */ /* Order is bottom up */ - my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ - my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ - my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ - - /* Update the stacking order. 2nd panel will be on top */ - update_panels(); - - /* Show it on the screen */ - doupdate(); - - getch(); - endwin(); -} -</span></font> -</pre></td> -</tr> -</table> -</div> -<p>As you can see, above program follows a simple flow as -explained. The windows are created with newwin() and then they are -attached to panels with new_panel(). As we attach one panel after -another, the stack of panels gets updated. To put them on screen -update_panels() and doupdate() are called.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PANELBROWSING" id="PANELBROWSING">16.3. -Panel Window Browsing</a></h3> -<p>A slightly complicated example is given below. This program -creates 3 windows which can be cycled through using tab. Have a -look at the code.</p> -<div class="EXAMPLE"><a name="PPABR" id="PPABR"></a> -<p><b>Example 15. Panel Window Browsing Example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <panel.h> - -#define NLINES 10 -#define NCOLS 40 - -void init_wins(WINDOW **wins, int n); -void win_show(WINDOW *win, char *label, int label_color); -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); - -int main() -{ WINDOW *my_wins[3]; - PANEL *my_panels[3]; - PANEL *top; - int ch; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - /* Initialize all the colors */ - init_pair(1, COLOR_RED, COLOR_BLACK); - init_pair(2, COLOR_GREEN, COLOR_BLACK); - init_pair(3, COLOR_BLUE, COLOR_BLACK); - init_pair(4, COLOR_CYAN, COLOR_BLACK); - - init_wins(my_wins, 3); - - /* Attach a panel to each window */ /* Order is bottom up */ - my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ - my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ - my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ - - /* Set up the user pointers to the next panel */ - set_panel_userptr(my_panels[0], my_panels[1]); - set_panel_userptr(my_panels[1], my_panels[2]); - set_panel_userptr(my_panels[2], my_panels[0]); - - /* Update the stacking order. 2nd panel will be on top */ - update_panels(); - - /* Show it on the screen */ - attron(COLOR_PAIR(4)); - mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); - attroff(COLOR_PAIR(4)); - doupdate(); - - top = my_panels[2]; - while((ch = getch()) != KEY_F(1)) - { switch(ch) - { case 9: - top = (PANEL *)panel_userptr(top); - top_panel(top); - break; - } - update_panels(); - doupdate(); - } - endwin(); - return 0; -} - -/* Put all the windows */ -void init_wins(WINDOW **wins, int n) -{ int x, y, i; - char label[80]; - - y = 2; - x = 10; - for(i = 0; i < n; ++i) - { wins[i] = newwin(NLINES, NCOLS, y, x); - sprintf(label, "Window Number %d", i + 1); - win_show(wins[i], label, i + 1); - y += 3; - x += 7; - } -} - -/* Show the window with a border and a label */ -void win_show(WINDOW *win, char *label, int label_color) -{ int startx, starty, height, width; - - getbegyx(win, starty, startx); - getmaxyx(win, height, width); - - box(win, 0, 0); - mvwaddch(win, 2, 0, ACS_LTEE); - mvwhline(win, 2, 1, ACS_HLINE, width - 2); - mvwaddch(win, 2, width - 1, ACS_RTEE); - - print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); -} - -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) -{ int length, x, y; - float temp; - - if(win == NULL) - win = stdscr; - getyx(win, y, x); - if(startx != 0) - x = startx; - if(starty != 0) - y = starty; - if(width == 0) - width = 80; - - length = strlen(string); - temp = (width - length)/ 2; - x = startx + (int)temp; - wattron(win, color); - mvwprintw(win, y, x, "%s", string); - wattroff(win, color); - refresh(); -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="USERPTRUSING" id="USERPTRUSING">16.4. -Using User Pointers</a></h3> -<p>In the above example I used user pointers to find out the next -window in the cycle. We can attach custom information to the panel -by specifying a user pointer, which can point to any information -you want to store. In this case I stored the pointer to the next -panel in the cycle. User pointer for a panel can be set with the -function <var class="LITERAL">set_panel_userptr()</var>. It can be -accessed using the function <var class= -"LITERAL">panel_userptr()</var> which will return the user pointer -for the panel given as argument. After finding the next panel in -the cycle It's brought to the top by the function top_panel(). This -function brings the panel given as argument to the top of the panel -stack.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PANELMOVERESIZE" id= -"PANELMOVERESIZE">16.5. Moving and Resizing Panels</a></h3> -<p>The function <var class="LITERAL">move_panel()</var> can be used -to move a panel to the desired location. It does not change the -position of the panel in the stack. Make sure that you use -move_panel() instead mvwin() on the window associated with the -panel.</p> -<p>Resizing a panel is slightly complex. There is no straight -forward function just to resize the window associated with a panel. -A solution to resize a panel is to create a new window with the -desired sizes, change the window associated with the panel using -replace_panel(). Don't forget to delete the old window. The window -associated with a panel can be found by using the function -panel_window().</p> -<p>The following program shows these concepts, in supposedly simple -program. You can cycle through the window with <TAB> as -usual. To resize or move the active panel press 'r' for resize 'm' -for moving. Then use arrow keys to resize or move it to the desired -way and press enter to end your resizing or moving. This example -makes use of user data to get the required data to do the -operations.</p> -<div class="EXAMPLE"><a name="PPARE" id="PPARE"></a> -<p><b>Example 16. Panel Moving and Resizing example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <panel.h> - -typedef struct _PANEL_DATA { - int x, y, w, h; - char label[80]; - int label_color; - PANEL *next; -}PANEL_DATA; - -#define NLINES 10 -#define NCOLS 40 - -void init_wins(WINDOW **wins, int n); -void win_show(WINDOW *win, char *label, int label_color); -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); -void set_user_ptrs(PANEL **panels, int n); - -int main() -{ WINDOW *my_wins[3]; - PANEL *my_panels[3]; - PANEL_DATA *top; - PANEL *stack_top; - WINDOW *temp_win, *old_win; - int ch; - int newx, newy, neww, newh; - int size = FALSE, move = FALSE; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - /* Initialize all the colors */ - init_pair(1, COLOR_RED, COLOR_BLACK); - init_pair(2, COLOR_GREEN, COLOR_BLACK); - init_pair(3, COLOR_BLUE, COLOR_BLACK); - init_pair(4, COLOR_CYAN, COLOR_BLACK); - - init_wins(my_wins, 3); - - /* Attach a panel to each window */ /* Order is bottom up */ - my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ - my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ - my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ - - set_user_ptrs(my_panels, 3); - /* Update the stacking order. 2nd panel will be on top */ - update_panels(); - - /* Show it on the screen */ - attron(COLOR_PAIR(4)); - mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing"); - mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); - attroff(COLOR_PAIR(4)); - doupdate(); - - stack_top = my_panels[2]; - top = (PANEL_DATA *)panel_userptr(stack_top); - newx = top->x; - newy = top->y; - neww = top->w; - newh = top->h; - while((ch = getch()) != KEY_F(1)) - { switch(ch) - { case 9: /* Tab */ - top = (PANEL_DATA *)panel_userptr(stack_top); - top_panel(top->next); - stack_top = top->next; - top = (PANEL_DATA *)panel_userptr(stack_top); - newx = top->x; - newy = top->y; - neww = top->w; - newh = top->h; - break; - case 'r': /* Re-Size*/ - size = TRUE; - attron(COLOR_PAIR(4)); - mvprintw(LINES - 4, 0, "Entered Resizing :Use Arrow Keys to resize and press <ENTER> to end resizing"); - refresh(); - attroff(COLOR_PAIR(4)); - break; - case 'm': /* Move */ - attron(COLOR_PAIR(4)); - mvprintw(LINES - 4, 0, "Entered Moving: Use Arrow Keys to Move and press <ENTER> to end moving"); - refresh(); - attroff(COLOR_PAIR(4)); - move = TRUE; - break; - case KEY_LEFT: - if(size == TRUE) - { --newx; - ++neww; - } - if(move == TRUE) - --newx; - break; - case KEY_RIGHT: - if(size == TRUE) - { ++newx; - --neww; - } - if(move == TRUE) - ++newx; - break; - case KEY_UP: - if(size == TRUE) - { --newy; - ++newh; - } - if(move == TRUE) - --newy; - break; - case KEY_DOWN: - if(size == TRUE) - { ++newy; - --newh; - } - if(move == TRUE) - ++newy; - break; - case 10: /* Enter */ - move(LINES - 4, 0); - clrtoeol(); - refresh(); - if(size == TRUE) - { old_win = panel_window(stack_top); - temp_win = newwin(newh, neww, newy, newx); - replace_panel(stack_top, temp_win); - win_show(temp_win, top->label, top->label_color); - delwin(old_win); - size = FALSE; - } - if(move == TRUE) - { move_panel(stack_top, newy, newx); - move = FALSE; - } - break; - - } - attron(COLOR_PAIR(4)); - mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing"); - mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); - attroff(COLOR_PAIR(4)); - refresh(); - update_panels(); - doupdate(); - } - endwin(); - return 0; -} - -/* Put all the windows */ -void init_wins(WINDOW **wins, int n) -{ int x, y, i; - char label[80]; - - y = 2; - x = 10; - for(i = 0; i < n; ++i) - { wins[i] = newwin(NLINES, NCOLS, y, x); - sprintf(label, "Window Number %d", i + 1); - win_show(wins[i], label, i + 1); - y += 3; - x += 7; - } -} - -/* Set the PANEL_DATA structures for individual panels */ -void set_user_ptrs(PANEL **panels, int n) -{ PANEL_DATA *ptrs; - WINDOW *win; - int x, y, w, h, i; - char temp[80]; - - ptrs = (PANEL_DATA *)calloc(n, sizeof(PANEL_DATA)); - - for(i = 0;i < n; ++i) - { win = panel_window(panels[i]); - getbegyx(win, y, x); - getmaxyx(win, h, w); - ptrs[i].x = x; - ptrs[i].y = y; - ptrs[i].w = w; - ptrs[i].h = h; - sprintf(temp, "Window Number %d", i + 1); - strcpy(ptrs[i].label, temp); - ptrs[i].label_color = i + 1; - if(i + 1 == n) - ptrs[i].next = panels[0]; - else - ptrs[i].next = panels[i + 1]; - set_panel_userptr(panels[i], &ptrs[i]); - } -} - -/* Show the window with a border and a label */ -void win_show(WINDOW *win, char *label, int label_color) -{ int startx, starty, height, width; - - getbegyx(win, starty, startx); - getmaxyx(win, height, width); - - box(win, 0, 0); - mvwaddch(win, 2, 0, ACS_LTEE); - mvwhline(win, 2, 1, ACS_HLINE, width - 2); - mvwaddch(win, 2, width - 1, ACS_RTEE); - - print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); -} - -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) -{ int length, x, y; - float temp; - - if(win == NULL) - win = stdscr; - getyx(win, y, x); - if(startx != 0) - x = startx; - if(starty != 0) - y = starty; - if(width == 0) - width = 80; - - length = strlen(string); - temp = (width - length)/ 2; - x = startx + (int)temp; - wattron(win, color); - mvwprintw(win, y, x, "%s", string); - wattroff(win, color); - refresh(); -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>Concentrate on the main while loop. Once it finds out the type -of key pressed, it takes appropriate action. If 'r' is pressed -resizing mode is started. After this the new sizes are updated as -the user presses the arrow keys. When the user presses -<ENTER> present selection ends and panel is resized by using -the concept explained. While in resizing mode the program doesn't -show how the window is getting resized. It's left as an exercise to -the reader to print a dotted border while it gets resized to a new -position.</p> -<p>When the user presses 'm' the move mode starts. This is a bit -simpler than resizing. As the arrow keys are pressed the new -position is updated and pressing of <ENTER> causes the panel -to be moved by calling the function move_panel().</p> -<p>In this program the user data which is represented as -PANEL_DATA, plays very important role in finding the associated -information with a panel. As written in the comments, the -PANEL_DATA stores the panel sizes, label, label color and a pointer -to the next panel in the cycle.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PANELSHOWHIDE" id="PANELSHOWHIDE">16.6. -Hiding and Showing Panels</a></h3> -<p>A Panel can be hidden by using the function hide_panel(). This -function merely removes it form the stack of panels, thus hiding it -on the screen once you do update_panels() and doupdate(). It -doesn't destroy the PANEL structure associated with the hidden -panel. It can be shown again by using the show_panel() -function.</p> -<p>The following program shows the hiding of panels. Press 'a' or -'b' or 'c' to show or hide first, second and third windows -respectively. It uses a user data with a small variable hide, which -keeps track of whether the window is hidden or not. For some reason -the function <var class="LITERAL">panel_hidden()</var> which tells -whether a panel is hidden or not is not working. A bug report was -also presented by Michael Andres <a href= -"http://www.geocrawler.com/archives/3/344/1999/9/0/2643549/" -target="_top">here</a></p> -<div class="EXAMPLE"><a name="PPAHI" id="PPAHI"></a> -<p><b>Example 17. Panel Hiding and Showing example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <panel.h> - -typedef struct _PANEL_DATA { - int hide; /* TRUE if panel is hidden */ -}PANEL_DATA; - -#define NLINES 10 -#define NCOLS 40 - -void init_wins(WINDOW **wins, int n); -void win_show(WINDOW *win, char *label, int label_color); -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); - -int main() -{ WINDOW *my_wins[3]; - PANEL *my_panels[3]; - PANEL_DATA panel_datas[3]; - PANEL_DATA *temp; - int ch; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - /* Initialize all the colors */ - init_pair(1, COLOR_RED, COLOR_BLACK); - init_pair(2, COLOR_GREEN, COLOR_BLACK); - init_pair(3, COLOR_BLUE, COLOR_BLACK); - init_pair(4, COLOR_CYAN, COLOR_BLACK); - - init_wins(my_wins, 3); - - /* Attach a panel to each window */ /* Order is bottom up */ - my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ - my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ - my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ - - /* Initialize panel datas saying that nothing is hidden */ - panel_datas[0].hide = FALSE; - panel_datas[1].hide = FALSE; - panel_datas[2].hide = FALSE; - - set_panel_userptr(my_panels[0], &panel_datas[0]); - set_panel_userptr(my_panels[1], &panel_datas[1]); - set_panel_userptr(my_panels[2], &panel_datas[2]); - - /* Update the stacking order. 2nd panel will be on top */ - update_panels(); - - /* Show it on the screen */ - attron(COLOR_PAIR(4)); - mvprintw(LINES - 3, 0, "Show or Hide a window with 'a'(first window) 'b'(Second Window) 'c'(Third Window)"); - mvprintw(LINES - 2, 0, "F1 to Exit"); - - attroff(COLOR_PAIR(4)); - doupdate(); - - while((ch = getch()) != KEY_F(1)) - { switch(ch) - { case 'a': - temp = (PANEL_DATA *)panel_userptr(my_panels[0]); - if(temp->hide == FALSE) - { hide_panel(my_panels[0]); - temp->hide = TRUE; - } - else - { show_panel(my_panels[0]); - temp->hide = FALSE; - } - break; - case 'b': - temp = (PANEL_DATA *)panel_userptr(my_panels[1]); - if(temp->hide == FALSE) - { hide_panel(my_panels[1]); - temp->hide = TRUE; - } - else - { show_panel(my_panels[1]); - temp->hide = FALSE; - } - break; - case 'c': - temp = (PANEL_DATA *)panel_userptr(my_panels[2]); - if(temp->hide == FALSE) - { hide_panel(my_panels[2]); - temp->hide = TRUE; - } - else - { show_panel(my_panels[2]); - temp->hide = FALSE; - } - break; - } - update_panels(); - doupdate(); - } - endwin(); - return 0; -} - -/* Put all the windows */ -void init_wins(WINDOW **wins, int n) -{ int x, y, i; - char label[80]; - - y = 2; - x = 10; - for(i = 0; i < n; ++i) - { wins[i] = newwin(NLINES, NCOLS, y, x); - sprintf(label, "Window Number %d", i + 1); - win_show(wins[i], label, i + 1); - y += 3; - x += 7; - } -} - -/* Show the window with a border and a label */ -void win_show(WINDOW *win, char *label, int label_color) -{ int startx, starty, height, width; - - getbegyx(win, starty, startx); - getmaxyx(win, height, width); - - box(win, 0, 0); - mvwaddch(win, 2, 0, ACS_LTEE); - mvwhline(win, 2, 1, ACS_HLINE, width - 2); - mvwaddch(win, 2, width - 1, ACS_RTEE); - - print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); -} - -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) -{ int length, x, y; - float temp; - - if(win == NULL) - win = stdscr; - getyx(win, y, x); - if(startx != 0) - x = startx; - if(starty != 0) - y = starty; - if(width == 0) - width = 80; - - length = strlen(string); - temp = (width - length)/ 2; - x = startx + (int)temp; - wattron(win, color); - mvwprintw(win, y, x, "%s", string); - wattroff(win, color); - refresh(); -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PANELABOVE" id="PANELABOVE">16.7. -panel_above() and panel_below() Functions</a></h3> -<p>The functions <var class="LITERAL">panel_above()</var> and -<var class="LITERAL">panel_below()</var> can be used to find out -the panel above and below a panel. If the argument to these -functions is NULL, then they return a pointer to bottom panel and -top panel respectively.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="MENUS" id="MENUS">17. Menus -Library</a></h2> -<p>The menus library provides a nice extension to basic curses, -through which you can create menus. It provides a set of functions -to create menus. But they have to be customized to give a nicer -look, with colors etc. Let's get into the details.</p> -<p>A menu is a screen display that assists the user to choose some -subset of a given set of items. To put it simple, a menu is a -collection of items from which one or more items can be chosen. -Some readers might not be aware of multiple item selection -capability. Menu library provides functionality to write menus from -which the user can chose more than one item as the preferred -choice. This is dealt with in a later section. Now it is time for -some rudiments.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MENUBASICS" id="MENUBASICS">17.1. The -Basics</a></h3> -<p>To create menus, you first create items, and then post the menu -to the display. After that, all the processing of user responses is -done in an elegant function menu_driver() which is the work horse -of any menu program.</p> -<p>The general flow of control of a menu program looks like -this.</p> -<ol type="1"> -<li> -<p>Initialize curses</p> -</li> -<li> -<p>Create items using new_item(). You can specify a name and -description for the items.</p> -</li> -<li> -<p>Create the menu with new_menu() by specifying the items to be -attached with.</p> -</li> -<li> -<p>Post the menu with menu_post() and refresh the screen.</p> -</li> -<li> -<p>Process the user requests with a loop and do necessary updates -to menu with menu_driver.</p> -</li> -<li> -<p>Unpost the menu with menu_unpost()</p> -</li> -<li> -<p>Free the memory allocated to menu by free_menu()</p> -</li> -<li> -<p>Free the memory allocated to the items with free_item()</p> -</li> -<li> -<p>End curses</p> -</li> -</ol> -<p>Let's see a program which prints a simple menu and updates the -current selection with up, down arrows.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="COMPILEMENUS" id="COMPILEMENUS">17.2. -Compiling With the Menu Library</a></h3> -<p>To use menu library functions, you have to include menu.h and to -link the program with menu library the flag -lmenu should be added -along with -lncurses in that order.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> #include <menu.h> - . - . - . - - compile and link: gcc <program file> -lmenu -lncurses</font> -</pre></td> -</tr> -</table> -<div class="EXAMPLE"><a name="MMESI" id="MMESI"></a> -<p><b>Example 18. Menu Basics</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <curses.h> -#include <menu.h> - -#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) -#define CTRLD 4 - -char *choices[] = { - "Choice 1", - "Choice 2", - "Choice 3", - "Choice 4", - "Exit", - }; - -int main() -{ ITEM **my_items; - int c; - MENU *my_menu; - int n_choices, i; - ITEM *cur_item; - - - initscr(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - n_choices = ARRAY_SIZE(choices); - my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); - - for(i = 0; i < n_choices; ++i) - my_items[i] = new_item(choices[i], choices[i]); - my_items[n_choices] = (ITEM *)NULL; - - my_menu = new_menu((ITEM **)my_items); - mvprintw(LINES - 2, 0, "F1 to Exit"); - post_menu(my_menu); - refresh(); - - while((c = getch()) != KEY_F(1)) - { switch(c) - { case KEY_DOWN: - menu_driver(my_menu, REQ_DOWN_ITEM); - break; - case KEY_UP: - menu_driver(my_menu, REQ_UP_ITEM); - break; - } - } - - free_item(my_items[0]); - free_item(my_items[1]); - free_menu(my_menu); - endwin(); -} - </span></font> -</pre></td> -</tr> -</table> -</div> -<p>This program demonstrates the basic concepts involved in -creating a menu using menus library. First we create the items -using new_item() and then attach them to the menu with new_menu() -function. After posting the menu and refreshing the screen, the -main processing loop starts. It reads user input and takes -corresponding action. The function menu_driver() is the main work -horse of the menu system. The second parameter to this function -tells what's to be done with the menu. According to the parameter, -menu_driver() does the corresponding task. The value can be either -a menu navigational request, an ascii character, or a KEY_MOUSE -special key associated with a mouse event.</p> -<p>The menu_driver accepts following navigational requests.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> REQ_LEFT_ITEM Move left to an item. - REQ_RIGHT_ITEM Move right to an item. - REQ_UP_ITEM Move up to an item. - REQ_DOWN_ITEM Move down to an item. - REQ_SCR_ULINE Scroll up a line. - REQ_SCR_DLINE Scroll down a line. - REQ_SCR_DPAGE Scroll down a page. - REQ_SCR_UPAGE Scroll up a page. - REQ_FIRST_ITEM Move to the first item. - REQ_LAST_ITEM Move to the last item. - REQ_NEXT_ITEM Move to the next item. - REQ_PREV_ITEM Move to the previous item. - REQ_TOGGLE_ITEM Select/deselect an item. - REQ_CLEAR_PATTERN Clear the menu pattern buffer. - REQ_BACK_PATTERN Delete the previous character from the pattern buffer. - REQ_NEXT_MATCH Move to the next item matching the pattern match. - REQ_PREV_MATCH Move to the previous item matching the pattern match. </font> -</pre></td> -</tr> -</table> -<p>Don't get overwhelmed by the number of options. We will see them -slowly one after another. The options of interest in this example -are REQ_UP_ITEM and REQ_DOWN_ITEM. These two options when passed to -menu_driver, menu driver updates the current item to one item up or -down respectively.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MENUDRIVER" id="MENUDRIVER">17.3. Menu -Driver: The work horse of the menu system</a></h3> -<p>As you have seen in the above example, menu_driver plays an -important role in updating the menu. It is very important to -understand various options it takes and what they do. As explained -above, the second parameter to menu_driver() can be either a -navigational request, a printable character or a KEY_MOUSE key. -Let's dissect the different navigational requests.</p> -<ul> -<li> -<p><em>REQ_LEFT_ITEM and REQ_RIGHT_ITEM</em></p> -<p>A Menu can be displayed with multiple columns for more than one -item. This can be done by using the <var class= -"LITERAL">menu_format()</var>function. When a multi columnar menu -is displayed these requests cause the menu driver to move the -current selection to left or right.</p> -</li> -<li> -<p><em>REQ_UP_ITEM and REQ_DOWN_ITEM</em></p> -<p>These two options you have seen in the above example. These -options when given, makes the menu_driver to move the current -selection to an item up or down.</p> -</li> -<li> -<p><em>REQ_SCR_* options</em></p> -<p>The four options REQ_SCR_ULINE, REQ_SCR_DLINE, REQ_SCR_DPAGE, -REQ_SCR_UPAGE are related to scrolling. If all the items in the -menu cannot be displayed in the menu sub window, then the menu is -scrollable. These requests can be given to the menu_driver to do -the scrolling either one line up, down or one page down or up -respectively.</p> -</li> -<li> -<p><em>REQ_FIRST_ITEM, REQ_LAST_ITEM, REQ_NEXT_ITEM and -REQ_PREV_ITEM</em></p> -<p>These requests are self explanatory.</p> -</li> -<li> -<p><em>REQ_TOGGLE_ITEM</em></p> -<p>This request when given, toggles the present selection. This -option is to be used only in a multi valued menu. So to use this -request the option O_ONEVALUE must be off. This option can be made -off or on with set_menu_opts().</p> -</li> -<li> -<p><em>Pattern Requests</em></p> -<p>Every menu has an associated pattern buffer, which is used to -find the nearest match to the ascii characters entered by the user. -Whenever ascii characters are given to menu_driver, it puts in to -the pattern buffer. It also tries to find the nearest match to the -pattern in the items list and moves current selection to that item. -The request REQ_CLEAR_PATTERN clears the pattern buffer. The -request REQ_BACK_PATTERN deletes the previous character in the -pattern buffer. In case the pattern matches more than one item then -the matched items can be cycled through REQ_NEXT_MATCH and -REQ_PREV_MATCH which move the current selection to the next and -previous matches respectively.</p> -</li> -<li> -<p><em>Mouse Requests</em></p> -<p>In case of KEY_MOUSE requests, according to the mouse position -an action is taken accordingly. The action to be taken is explained -in the man page as,</p> -<table border="0" bgcolor="#E0E0E0" width="90%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"><em> If the second argument is the KEY_MOUSE special key, the - associated mouse event is translated into one of the above - pre-defined requests. Currently only clicks in the user - window (e.g. inside the menu display area or the decora­ - tion window) are handled. If you click above the display - region of the menu, a REQ_SCR_ULINE is generated, if you - doubleclick a REQ_SCR_UPAGE is generated and if you - tripleclick a REQ_FIRST_ITEM is generated. If you click - below the display region of the menu, a REQ_SCR_DLINE is - generated, if you doubleclick a REQ_SCR_DPAGE is generated - and if you tripleclick a REQ_LAST_ITEM is generated. If - you click at an item inside the display area of the menu, - the menu cursor is positioned to that item.</em></font> -</pre></td> -</tr> -</table> -</li> -</ul> -<p>Each of the above requests will be explained in the following -lines with several examples whenever appropriate.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MENUWINDOWS" id="MENUWINDOWS">17.4. Menu -Windows</a></h3> -<p>Every menu created is associated with a window and a sub window. -The menu window displays any title or border associated with the -menu. The menu sub window displays the menu items currently -available for selection. But we didn't specify any window or sub -window in the simple example. When a window is not specified, -stdscr is taken as the main window, and then menu system calculates -the sub window size required for the display of items. Then items -are displayed in the calculated sub window. So let's play with -these windows and display a menu with a border and a title.</p> -<div class="EXAMPLE"><a name="MMEWI" id="MMEWI"></a> -<p><b>Example 19. Menu Windows Usage example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <menu.h> - -#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) -#define CTRLD 4 - -char *choices[] = { - "Choice 1", - "Choice 2", - "Choice 3", - "Choice 4", - "Exit", - (char *)NULL, - }; -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); - -int main() -{ ITEM **my_items; - int c; - MENU *my_menu; - WINDOW *my_menu_win; - int n_choices, i; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - init_pair(1, COLOR_RED, COLOR_BLACK); - - /* Create items */ - n_choices = ARRAY_SIZE(choices); - my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); - for(i = 0; i < n_choices; ++i) - my_items[i] = new_item(choices[i], choices[i]); - - /* Crate menu */ - my_menu = new_menu((ITEM **)my_items); - - /* Create the window to be associated with the menu */ - my_menu_win = newwin(10, 40, 4, 4); - keypad(my_menu_win, TRUE); - - /* Set main window and sub window */ - set_menu_win(my_menu, my_menu_win); - set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1)); - - /* Set menu mark to the string " * " */ - set_menu_mark(my_menu, " * "); - - /* Print a border around the main window and print a title */ - box(my_menu_win, 0, 0); - print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1)); - mvwaddch(my_menu_win, 2, 0, ACS_LTEE); - mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38); - mvwaddch(my_menu_win, 2, 39, ACS_RTEE); - mvprintw(LINES - 2, 0, "F1 to exit"); - refresh(); - - /* Post the menu */ - post_menu(my_menu); - wrefresh(my_menu_win); - - while((c = wgetch(my_menu_win)) != KEY_F(1)) - { switch(c) - { case KEY_DOWN: - menu_driver(my_menu, REQ_DOWN_ITEM); - break; - case KEY_UP: - menu_driver(my_menu, REQ_UP_ITEM); - break; - } - wrefresh(my_menu_win); - } - - /* Unpost and free all the memory taken up */ - unpost_menu(my_menu); - free_menu(my_menu); - for(i = 0; i < n_choices; ++i) - free_item(my_items[i]); - endwin(); -} - -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) -{ int length, x, y; - float temp; - - if(win == NULL) - win = stdscr; - getyx(win, y, x); - if(startx != 0) - x = startx; - if(starty != 0) - y = starty; - if(width == 0) - width = 80; - - length = strlen(string); - temp = (width - length)/ 2; - x = startx + (int)temp; - wattron(win, color); - mvwprintw(win, y, x, "%s", string); - wattroff(win, color); - refresh(); -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>This example creates a menu with a title, border, a fancy line -separating title and the items. As you can see, in order to attach -a window to a menu the function set_menu_win() has to be used. Then -we attach the sub window also. This displays the items in the sub -window. You can also set the mark string which gets displayed to -the left of the selected item with set_menu_mark().</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="SCROLLMENUS" id="SCROLLMENUS">17.5. -Scrolling Menus</a></h3> -<p>If the sub window given for a window is not big enough to show -all the items, then the menu will be scrollable. When you are on -the last item in the present list, if you send REQ_DOWN_ITEM, it -gets translated into REQ_SCR_DLINE and the menu scrolls by one -item. You can manually give REQ_SCR_ operations to do scrolling. -Let's see how it can be done.</p> -<div class="EXAMPLE"><a name="MMESC" id="MMESC"></a> -<p><b>Example 20. Scrolling Menus example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <curses.h> -#include <menu.h> - -#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) -#define CTRLD 4 - -char *choices[] = { - "Choice 1", - "Choice 2", - "Choice 3", - "Choice 4", - "Choice 5", - "Choice 6", - "Choice 7", - "Choice 8", - "Choice 9", - "Choice 10", - "Exit", - (char *)NULL, - }; -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); - -int main() -{ ITEM **my_items; - int c; - MENU *my_menu; - WINDOW *my_menu_win; - int n_choices, i; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - init_pair(1, COLOR_RED, COLOR_BLACK); - init_pair(2, COLOR_CYAN, COLOR_BLACK); - - /* Create items */ - n_choices = ARRAY_SIZE(choices); - my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); - for(i = 0; i < n_choices; ++i) - my_items[i] = new_item(choices[i], choices[i]); - - /* Crate menu */ - my_menu = new_menu((ITEM **)my_items); - - /* Create the window to be associated with the menu */ - my_menu_win = newwin(10, 40, 4, 4); - keypad(my_menu_win, TRUE); - - /* Set main window and sub window */ - set_menu_win(my_menu, my_menu_win); - set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1)); - set_menu_format(my_menu, 5, 1); - - /* Set menu mark to the string " * " */ - set_menu_mark(my_menu, " * "); - - /* Print a border around the main window and print a title */ - box(my_menu_win, 0, 0); - print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1)); - mvwaddch(my_menu_win, 2, 0, ACS_LTEE); - mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38); - mvwaddch(my_menu_win, 2, 39, ACS_RTEE); - - /* Post the menu */ - post_menu(my_menu); - wrefresh(my_menu_win); - - attron(COLOR_PAIR(2)); - mvprintw(LINES - 2, 0, "Use PageUp and PageDown to scoll down or up a page of items"); - mvprintw(LINES - 1, 0, "Arrow Keys to navigate (F1 to Exit)"); - attroff(COLOR_PAIR(2)); - refresh(); - - while((c = wgetch(my_menu_win)) != KEY_F(1)) - { switch(c) - { case KEY_DOWN: - menu_driver(my_menu, REQ_DOWN_ITEM); - break; - case KEY_UP: - menu_driver(my_menu, REQ_UP_ITEM); - break; - case KEY_NPAGE: - menu_driver(my_menu, REQ_SCR_DPAGE); - break; - case KEY_PPAGE: - menu_driver(my_menu, REQ_SCR_UPAGE); - break; - } - wrefresh(my_menu_win); - } - - /* Unpost and free all the memory taken up */ - unpost_menu(my_menu); - free_menu(my_menu); - for(i = 0; i < n_choices; ++i) - free_item(my_items[i]); - endwin(); -} - -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) -{ int length, x, y; - float temp; - - if(win == NULL) - win = stdscr; - getyx(win, y, x); - if(startx != 0) - x = startx; - if(starty != 0) - y = starty; - if(width == 0) - width = 80; - - length = strlen(string); - temp = (width - length)/ 2; - x = startx + (int)temp; - wattron(win, color); - mvwprintw(win, y, x, "%s", string); - wattroff(win, color); - refresh(); -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>This program is self-explanatory. In this example the number of -choices has been increased to ten, which is larger than our sub -window size which can hold 6 items. This message has to be -explicitly conveyed to the menu system with the function -set_menu_format(). In here we specify the number of rows and -columns we want to be displayed for a single page. We can specify -any number of items to be shown, in the rows variables, if it is -less than the height of the sub window. If the key pressed by the -user is a PAGE UP or PAGE DOWN, the menu is scrolled a page due to -the requests (REQ_SCR_DPAGE and REQ_SCR_UPAGE) given to -menu_driver().</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MULTICOLUMN" id="MULTICOLUMN">17.6. -Multi Columnar Menus</a></h3> -<p>In the above example you have seen how to use the function -set_menu_format(). I didn't mention what the cols variable (third -parameter) does. Well, If your sub window is wide enough, you can -opt to display more than one item per row. This can be specified in -the cols variable. To make things simpler, the following example -doesn't show descriptions for the items.</p> -<div class="EXAMPLE"><a name="MMEMUCO" id="MMEMUCO"></a> -<p><b>Example 21. Milt Columnar Menus Example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <curses.h> -#include <menu.h> - -#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) -#define CTRLD 4 - -char *choices[] = { - "Choice 1", "Choice 2", "Choice 3", "Choice 4", "Choice 5", - "Choice 6", "Choice 7", "Choice 8", "Choice 9", "Choice 10", - "Choice 11", "Choice 12", "Choice 13", "Choice 14", "Choice 15", - "Choice 16", "Choice 17", "Choice 18", "Choice 19", "Choice 20", - "Exit", - (char *)NULL, - }; - -int main() -{ ITEM **my_items; - int c; - MENU *my_menu; - WINDOW *my_menu_win; - int n_choices, i; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - init_pair(1, COLOR_RED, COLOR_BLACK); - init_pair(2, COLOR_CYAN, COLOR_BLACK); - - /* Create items */ - n_choices = ARRAY_SIZE(choices); - my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); - for(i = 0; i < n_choices; ++i) - my_items[i] = new_item(choices[i], choices[i]); - - /* Crate menu */ - my_menu = new_menu((ITEM **)my_items); - - /* Set menu option not to show the description */ - menu_opts_off(my_menu, O_SHOWDESC); - - /* Create the window to be associated with the menu */ - my_menu_win = newwin(10, 70, 4, 4); - keypad(my_menu_win, TRUE); - - /* Set main window and sub window */ - set_menu_win(my_menu, my_menu_win); - set_menu_sub(my_menu, derwin(my_menu_win, 6, 68, 3, 1)); - set_menu_format(my_menu, 5, 3); - set_menu_mark(my_menu, " * "); - - /* Print a border around the main window and print a title */ - box(my_menu_win, 0, 0); - - attron(COLOR_PAIR(2)); - mvprintw(LINES - 3, 0, "Use PageUp and PageDown to scroll"); - mvprintw(LINES - 2, 0, "Use Arrow Keys to navigate (F1 to Exit)"); - attroff(COLOR_PAIR(2)); - refresh(); - - /* Post the menu */ - post_menu(my_menu); - wrefresh(my_menu_win); - - while((c = wgetch(my_menu_win)) != KEY_F(1)) - { switch(c) - { case KEY_DOWN: - menu_driver(my_menu, REQ_DOWN_ITEM); - break; - case KEY_UP: - menu_driver(my_menu, REQ_UP_ITEM); - break; - case KEY_LEFT: - menu_driver(my_menu, REQ_LEFT_ITEM); - break; - case KEY_RIGHT: - menu_driver(my_menu, REQ_RIGHT_ITEM); - break; - case KEY_NPAGE: - menu_driver(my_menu, REQ_SCR_DPAGE); - break; - case KEY_PPAGE: - menu_driver(my_menu, REQ_SCR_UPAGE); - break; - } - wrefresh(my_menu_win); - } - - /* Unpost and free all the memory taken up */ - unpost_menu(my_menu); - free_menu(my_menu); - for(i = 0; i < n_choices; ++i) - free_item(my_items[i]); - endwin(); -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>Watch the function call to set_menu_format(). It specifies the -number of columns to be 3, thus displaying 3 items per row. We have -also switched off the showing descriptions with the function -menu_opts_off(). There are couple of functions set_menu_opts(), -menu_opts_on() and menu_opts() which can be used to manipulate menu -options. The following menu options can be specified.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> O_ONEVALUE - Only one item can be selected for this menu. - - O_SHOWDESC - Display the item descriptions when the menu is - posted. - - O_ROWMAJOR - Display the menu in row-major order. - - O_IGNORECASE - Ignore the case when pattern-matching. - - O_SHOWMATCH - Move the cursor to within the item name while pat­ - tern-matching. - - O_NONCYCLIC - Don't wrap around next-item and previous-item, - requests to the other end of the menu.</font> -</pre></td> -</tr> -</table> -<p>All options are on by default. You can switch specific -attributes on or off with menu_opts_on() and menu_opts_off() -functions. You can also use set_menu_opts() to directly specify the -options. The argument to this function should be a OR ed value of -some of those above constants. The function menu_opts() can be used -to find out a menu's present options.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MULTIVALUEMENUS" id= -"MULTIVALUEMENUS">17.7. Multi Valued Menus</a></h3> -<p>You might be wondering what if you switch off the option -O_ONEVALUE. Then the menu becomes multi-valued. That means you can -select more than one item. This brings us to the request -REQ_TOGGLE_ITEM. Let's see it in action.</p> -<div class="EXAMPLE"><a name="MMETO" id="MMETO"></a> -<p><b>Example 22. Multi Valued Menus example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <curses.h> -#include <menu.h> - -#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) -#define CTRLD 4 - -char *choices[] = { - "Choice 1", - "Choice 2", - "Choice 3", - "Choice 4", - "Choice 5", - "Choice 6", - "Choice 7", - "Exit", - }; - -int main() -{ ITEM **my_items; - int c; - MENU *my_menu; - int n_choices, i; - ITEM *cur_item; - - /* Initialize curses */ - initscr(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - /* Initialize items */ - n_choices = ARRAY_SIZE(choices); - my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); - for(i = 0; i < n_choices; ++i) - my_items[i] = new_item(choices[i], choices[i]); - my_items[n_choices] = (ITEM *)NULL; - - my_menu = new_menu((ITEM **)my_items); - - /* Make the menu multi valued */ - menu_opts_off(my_menu, O_ONEVALUE); - - mvprintw(LINES - 3, 0, "Use <SPACE> to select or unselect an item."); - mvprintw(LINES - 2, 0, "<ENTER> to see presently selected items(F1 to Exit)"); - post_menu(my_menu); - refresh(); - - while((c = getch()) != KEY_F(1)) - { switch(c) - { case KEY_DOWN: - menu_driver(my_menu, REQ_DOWN_ITEM); - break; - case KEY_UP: - menu_driver(my_menu, REQ_UP_ITEM); - break; - case ' ': - menu_driver(my_menu, REQ_TOGGLE_ITEM); - break; - case 10: /* Enter */ - { char temp[200]; - ITEM **items; - - items = menu_items(my_menu); - temp[0] = '\0'; - for(i = 0; i < item_count(my_menu); ++i) - if(item_value(items[i]) == TRUE) - { strcat(temp, item_name(items[i])); - strcat(temp, " "); - } - move(20, 0); - clrtoeol(); - mvprintw(20, 0, temp); - refresh(); - } - break; - } - } - - free_item(my_items[0]); - free_item(my_items[1]); - free_menu(my_menu); - endwin(); -} - </span></font> -</pre></td> -</tr> -</table> -</div> -<p>Whew, A lot of new functions. Let's take them one after another. -Firstly, the REQ_TOGGLE_ITEM. In a multi-valued menu, the user -should be allowed to select or un select more than one item. The -request REQ_TOGGLE_ITEM toggles the present selection. In this case -when space is pressed REQ_TOGGLE_ITEM request is sent to -menu_driver to achieve the result.</p> -<p>Now when the user presses <ENTER> we show the items he -presently selected. First we find out the items associated with the -menu using the function menu_items(). Then we loop through the -items to find out if the item is selected or not. The function -item_value() returns TRUE if an item is selected. The function -item_count() returns the number of items in the menu. The item name -can be found with item_name(). You can also find the description -associated with an item using item_description().</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MENUOPT" id="MENUOPT">17.8. Menu -Options</a></h3> -<p>Well, by this time you must be itching for some difference in -your menu, with lots of functionality. I know. You want Colors !!!. -You want to create nice menus similar to those text mode <a href= -"http://www.jersey.net/~debinjoe/games/" target="_top">dos -games</a>. The functions set_menu_fore() and set_menu_back() can be -used to change the attribute of the selected item and unselected -item. The names are misleading. They don't change menu's foreground -or background which would have been useless.</p> -<p>The function set_menu_grey() can be used to set the display -attribute for the non-selectable items in the menu. This brings us -to the interesting option for an item the one and only -O_SELECTABLE. We can turn it off by the function item_opts_off() -and after that that item is not selectable. It's like a grayed item -in those fancy windows menus. Let's put these concepts in practice -with this example</p> -<div class="EXAMPLE"><a name="MMEAT" id="MMEAT"></a> -<p><b>Example 23. Menu Options example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <menu.h> - -#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) -#define CTRLD 4 - -char *choices[] = { - "Choice 1", - "Choice 2", - "Choice 3", - "Choice 4", - "Choice 5", - "Choice 6", - "Choice 7", - "Exit", - }; - -int main() -{ ITEM **my_items; - int c; - MENU *my_menu; - int n_choices, i; - ITEM *cur_item; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - init_pair(1, COLOR_RED, COLOR_BLACK); - init_pair(2, COLOR_GREEN, COLOR_BLACK); - init_pair(3, COLOR_MAGENTA, COLOR_BLACK); - - /* Initialize items */ - n_choices = ARRAY_SIZE(choices); - my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); - for(i = 0; i < n_choices; ++i) - my_items[i] = new_item(choices[i], choices[i]); - my_items[n_choices] = (ITEM *)NULL; - item_opts_off(my_items[3], O_SELECTABLE); - item_opts_off(my_items[6], O_SELECTABLE); - - /* Create menu */ - my_menu = new_menu((ITEM **)my_items); - - /* Set fore ground and back ground of the menu */ - set_menu_fore(my_menu, COLOR_PAIR(1) | A_REVERSE); - set_menu_back(my_menu, COLOR_PAIR(2)); - set_menu_grey(my_menu, COLOR_PAIR(3)); - - /* Post the menu */ - mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected"); - mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)"); - post_menu(my_menu); - refresh(); - - while((c = getch()) != KEY_F(1)) - { switch(c) - { case KEY_DOWN: - menu_driver(my_menu, REQ_DOWN_ITEM); - break; - case KEY_UP: - menu_driver(my_menu, REQ_UP_ITEM); - break; - case 10: /* Enter */ - move(20, 0); - clrtoeol(); - mvprintw(20, 0, "Item selected is : %s", - item_name(current_item(my_menu))); - pos_menu_cursor(my_menu); - break; - } - } - unpost_menu(my_menu); - for(i = 0; i < n_choices; ++i) - free_item(my_items[i]); - free_menu(my_menu); - endwin(); -} - </span></font> -</pre></td> -</tr> -</table> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MENUUSERPTR" id="MENUUSERPTR">17.9. The -useful User Pointer</a></h3> -<p>We can associate a user pointer with each item in the menu. It -works the same way as user pointer in panels. It's not touched by -menu system. You can store any thing you like in that. I usually -use it to store the function to be executed when the menu option is -chosen (It's selected and may be the user pressed -<ENTER>);</p> -<div class="EXAMPLE"><a name="MMEUS" id="MMEUS"></a> -<p><b>Example 24. Menu User Pointer Usage</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <curses.h> -#include <menu.h> - -#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) -#define CTRLD 4 - -char *choices[] = { - "Choice 1", - "Choice 2", - "Choice 3", - "Choice 4", - "Choice 5", - "Choice 6", - "Choice 7", - "Exit", - }; -void func(char *name); - -int main() -{ ITEM **my_items; - int c; - MENU *my_menu; - int n_choices, i; - ITEM *cur_item; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - init_pair(1, COLOR_RED, COLOR_BLACK); - init_pair(2, COLOR_GREEN, COLOR_BLACK); - init_pair(3, COLOR_MAGENTA, COLOR_BLACK); - - /* Initialize items */ - n_choices = ARRAY_SIZE(choices); - my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); - for(i = 0; i < n_choices; ++i) - { my_items[i] = new_item(choices[i], choices[i]); - /* Set the user pointer */ - set_item_userptr(my_items[i], func); - } - my_items[n_choices] = (ITEM *)NULL; - - /* Create menu */ - my_menu = new_menu((ITEM **)my_items); - - /* Post the menu */ - mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected"); - mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)"); - post_menu(my_menu); - refresh(); - - while((c = getch()) != KEY_F(1)) - { switch(c) - { case KEY_DOWN: - menu_driver(my_menu, REQ_DOWN_ITEM); - break; - case KEY_UP: - menu_driver(my_menu, REQ_UP_ITEM); - break; - case 10: /* Enter */ - { ITEM *cur; - void (*p)(char *); - - cur = current_item(my_menu); - p = item_userptr(cur); - p((char *)item_name(cur)); - pos_menu_cursor(my_menu); - break; - } - break; - } - } - unpost_menu(my_menu); - for(i = 0; i < n_choices; ++i) - free_item(my_items[i]); - free_menu(my_menu); - endwin(); -} - -void func(char *name) -{ move(20, 0); - clrtoeol(); - mvprintw(20, 0, "Item selected is : %s", name); -} </span></font> -</pre></td> -</tr> -</table> -</div> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="FORMS" id="FORMS">18. Forms -Library</a></h2> -<p>Well. If you have seen those forms on web pages which take input -from users and do various kinds of things, you might be wondering -how would any one create such forms in text mode display. It's -quite difficult to write those nifty forms in plain ncurses. Forms -library tries to provide a basic frame work to build and maintain -forms with ease. It has lot of features(functions) which manage -validation, dynamic expansion of fields etc.. Let's see it in full -flow.</p> -<p>A form is a collection of fields; each field can be either a -label(static text) or a data-entry location. The forms also library -provides functions to divide forms into multiple pages.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="FORMBASICS" id="FORMBASICS">18.1. The -Basics</a></h3> -<p>Forms are created in much the same way as menus. First the -fields related to the form are created with new_field(). You can -set options for the fields, so that they can be displayed with some -fancy attributes, validated before the field looses focus etc.. -Then the fields are attached to form. After this, the form can be -posted to display and is ready to receive inputs. On the similar -lines to menu_driver(), the form is manipulated with form_driver(). -We can send requests to form_driver to move focus to a certain -field, move cursor to end of the field etc.. After the user enters -values in the fields and validation done, form can be unposted and -memory allocated can be freed.</p> -<p>The general flow of control of a forms program looks like -this.</p> -<ol type="1"> -<li> -<p>Initialize curses</p> -</li> -<li> -<p>Create fields using new_field(). You can specify the height and -width of the field, and its position on the form.</p> -</li> -<li> -<p>Create the forms with new_form() by specifying the fields to be -attached with.</p> -</li> -<li> -<p>Post the form with form_post() and refresh the screen.</p> -</li> -<li> -<p>Process the user requests with a loop and do necessary updates -to form with form_driver.</p> -</li> -<li> -<p>Unpost the menu with form_unpost()</p> -</li> -<li> -<p>Free the memory allocated to menu by free_form()</p> -</li> -<li> -<p>Free the memory allocated to the items with free_field()</p> -</li> -<li> -<p>End curses</p> -</li> -</ol> -<p>As you can see, working with forms library is much similar to -handling menu library. The following examples will explore various -aspects of form processing. Let's start the journey with a simple -example. first.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="COMPILEFORMS" id="COMPILEFORMS">18.2. -Compiling With the Forms Library</a></h3> -<p>To use forms library functions, you have to include form.h and -to link the program with forms library the flag -lform should be -added along with -lncurses in that order.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"> #include <form.h> - . - . - . - - compile and link: gcc <program file> -lform -lncurses</font> -</pre></td> -</tr> -</table> -<div class="EXAMPLE"><a name="FFOSI" id="FFOSI"></a> -<p><b>Example 25. Forms Basics</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <form.h> - -int main() -{ FIELD *field[3]; - FORM *my_form; - int ch; - - /* Initialize curses */ - initscr(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - /* Initialize the fields */ - field[0] = new_field(1, 10, 4, 18, 0, 0); - field[1] = new_field(1, 10, 6, 18, 0, 0); - field[2] = NULL; - - /* Set field options */ - set_field_back(field[0], A_UNDERLINE); /* Print a line for the option */ - field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ - /* Field is filled up */ - set_field_back(field[1], A_UNDERLINE); - field_opts_off(field[1], O_AUTOSKIP); - - /* Create the form and post it */ - my_form = new_form(field); - post_form(my_form); - refresh(); - - mvprintw(4, 10, "Value 1:"); - mvprintw(6, 10, "Value 2:"); - refresh(); - - /* Loop through to get user requests */ - while((ch = getch()) != KEY_F(1)) - { switch(ch) - { case KEY_DOWN: - /* Go to next field */ - form_driver(my_form, REQ_NEXT_FIELD); - /* Go to the end of the present buffer */ - /* Leaves nicely at the last character */ - form_driver(my_form, REQ_END_LINE); - break; - case KEY_UP: - /* Go to previous field */ - form_driver(my_form, REQ_PREV_FIELD); - form_driver(my_form, REQ_END_LINE); - break; - default: - /* If this is a normal character, it gets */ - /* Printed */ - form_driver(my_form, ch); - break; - } - } - - /* Un post form and free the memory */ - unpost_form(my_form); - free_form(my_form); - free_field(field[0]); - free_field(field[1]); - - endwin(); - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>Above example is pretty straight forward. It creates two fields -with <var class="LITERAL">new_field()</var>. new_field() takes -height, width, starty, startx, number of offscreen rows and number -of additional working buffers. The fifth argument number of -offscreen rows specifies how much of the field to be shown. If it -is zero, the entire field is always displayed otherwise the form -will be scrollable when the user accesses not displayed parts of -the field. The forms library allocates one buffer per field to -store the data user enters. Using the last parameter to new_field() -we can specify it to allocate some additional buffers. These can be -used for any purpose you like.</p> -<p>After creating the fields, back ground attribute of both of them -is set to an underscore with set_field_back(). The AUTOSKIP option -is turned off using field_opts_off(). If this option is turned on, -focus will move to the next field in the form once the active field -is filled up completely.</p> -<p>After attaching the fields to the form, it is posted. Here on, -user inputs are processed in the while loop, by making -corresponding requests to form_driver. The details of all the -requests to the form_driver() are explained later.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PLAYFIELDS" id="PLAYFIELDS">18.3. -Playing with Fields</a></h3> -<p>Each form field is associated with a lot of attributes. They can -be manipulated to get the required effect and to have fun !!!. So -why wait?</p> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="FETCHINFO" id="FETCHINFO">18.3.1. -Fetching Size and Location of Field</a></h4> -<p>The parameters we have given at the time of creation of a field -can be retrieved with field_info(). It returns height, width, -starty, startx, number of offscreen rows, and number of additional -buffers into the parameters given to it. It is a sort of inverse of -new_field().</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int field_info( FIELD *field, /* field from which to fetch */ - int *height, *int width, /* field size */ - int *top, int *left, /* upper left corner */ - int *offscreen, /* number of offscreen rows */ - int *nbuf); /* number of working buffers */</font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="MOVEFIELD" id="MOVEFIELD">18.3.2. Moving -the field</a></h4> -<p>The location of the field can be moved to a different position -with move_field().</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int move_field( FIELD *field, /* field to alter */ - int top, int left); /* new upper-left corner */</font> -</pre></td> -</tr> -</table> -<p>As usual, the changed position can be queried with -field_infor().</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="JUSTIFYFIELD" id="JUSTIFYFIELD">18.3.3. -Field Justification</a></h4> -<p>The justification to be done for the field can be fixed using -the function set_field_just().</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> int set_field_just(FIELD *field, /* field to alter */ - int justmode); /* mode to set */ - int field_just(FIELD *field); /* fetch justify mode of field */</font> -</pre></td> -</tr> -</table> -<p>The justification mode valued accepted and returned by these -functions are NO_JUSTIFICATION, JUSTIFY_RIGHT, JUSTIFY_LEFT, or -JUSTIFY_CENTER.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="FIELDDISPATTRIB" id= -"FIELDDISPATTRIB">18.3.4. Field Display Attributes</a></h4> -<p>As you have seen, in the above example, display attribute for -the fields can be set with set_field_fore() and setfield_back(). -These functions set foreground and background attribute of the -fields. You can also specify a pad character which will be filled -in the unfilled portion of the field. The pad character is set with -a call to set_field_pad(). Default pad value is a space. The -functions field_fore(), field_back, field_pad() can be used to -query the present foreground, background attributes and pad -character for the field. The following list gives the usage of -functions.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> int set_field_fore(FIELD *field, /* field to alter */ - chtype attr); /* attribute to set */ - -chtype field_fore(FIELD *field); /* field to query */ - /* returns foreground attribute */ - -int set_field_back(FIELD *field, /* field to alter */ - chtype attr); /* attribute to set */ - -chtype field_back(FIELD *field); /* field to query */ - /* returns background attribute */ - -int set_field_pad(FIELD *field, /* field to alter */ - int pad); /* pad character to set */ - -chtype field_pad(FIELD *field); /* field to query */ - /* returns present pad character */ </font> -</pre></td> -</tr> -</table> -<p>Though above functions seem quite simple, using colors with -set_field_fore() may be frustrating in the beginning. Let me first -explain about foreground and background attributes of a field. The -foreground attribute is associated with the character. That means a -character in the field is printed with the attribute you have set -with set_field_fore(). Background attribute is the attribute used -to fill background of field, whether any character is there or not. -So what about colors? Since colors are always defined in pairs, -what is the right way to display colored fields? Here's an example -clarifying color attributes.</p> -<div class="EXAMPLE"><a name="FFOAT" id="FFOAT"></a> -<p><b>Example 26. Form Attributes example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <form.h> - -int main() -{ FIELD *field[3]; - FORM *my_form; - int ch; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - /* Initialize few color pairs */ - init_pair(1, COLOR_WHITE, COLOR_BLUE); - init_pair(2, COLOR_WHITE, COLOR_BLUE); - - /* Initialize the fields */ - field[0] = new_field(1, 10, 4, 18, 0, 0); - field[1] = new_field(1, 10, 6, 18, 0, 0); - field[2] = NULL; - - /* Set field options */ - set_field_fore(field[0], COLOR_PAIR(1));/* Put the field with blue background */ - set_field_back(field[0], COLOR_PAIR(2));/* and white foreground (characters */ - /* are printed in white */ - field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ - /* Field is filled up */ - set_field_back(field[1], A_UNDERLINE); - field_opts_off(field[1], O_AUTOSKIP); - - /* Create the form and post it */ - my_form = new_form(field); - post_form(my_form); - refresh(); - - set_current_field(my_form, field[0]); /* Set focus to the colored field */ - mvprintw(4, 10, "Value 1:"); - mvprintw(6, 10, "Value 2:"); - mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields"); - refresh(); - - /* Loop through to get user requests */ - while((ch = getch()) != KEY_F(1)) - { switch(ch) - { case KEY_DOWN: - /* Go to next field */ - form_driver(my_form, REQ_NEXT_FIELD); - /* Go to the end of the present buffer */ - /* Leaves nicely at the last character */ - form_driver(my_form, REQ_END_LINE); - break; - case KEY_UP: - /* Go to previous field */ - form_driver(my_form, REQ_PREV_FIELD); - form_driver(my_form, REQ_END_LINE); - break; - default: - /* If this is a normal character, it gets */ - /* Printed */ - form_driver(my_form, ch); - break; - } - } - - /* Un post form and free the memory */ - unpost_form(my_form); - free_form(my_form); - free_field(field[0]); - free_field(field[1]); - - endwin(); - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>Play with the color pairs and try to understand the foreground -and background attributes. In my programs using color attributes, I -usually set only the background with set_field_back(). Curses -simply doesn't allow defining individual color attributes.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="FIELDOPTIONBITS" id= -"FIELDOPTIONBITS">18.3.5. Field Option Bits</a></h4> -<p>There is also a large collection of field option bits you can -set to control various aspects of forms processing. You can -manipulate them with these functions:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_opts(FIELD *field, /* field to alter */ - int attr); /* attribute to set */ - -int field_opts_on(FIELD *field, /* field to alter */ - int attr); /* attributes to turn on */ - -int field_opts_off(FIELD *field, /* field to alter */ - int attr); /* attributes to turn off */ - -int field_opts(FIELD *field); /* field to query */ </font> -</pre></td> -</tr> -</table> -<p>The function set_field_opts() can be used to directly set -attributes of a field or you can choose to switch a few attributes -on and off with field_opts_on() and field_opts_off() selectively. -Anytime you can query the attributes of a field with field_opts(). -The following is the list of available options. By default, all -options are on.</p> -<div class="VARIABLELIST"> -<dl> -<dt>O_VISIBLE</dt> -<dd> -<p>Controls whether the field is visible on the screen. Can be used -during form processing to hide or pop up fields depending on the -value of parent fields.</p> -</dd> -<dt>O_ACTIVE</dt> -<dd> -<p>Controls whether the field is active during forms processing -(i.e. visited by form navigation keys). Can be used to make labels -or derived fields with buffer values alterable by the forms -application, not the user.</p> -</dd> -<dt>O_PUBLIC</dt> -<dd> -<p>Controls whether data is displayed during field entry. If this -option is turned off on a field, the library will accept and edit -data in that field, but it will not be displayed and the visible -field cursor will not move. You can turn off the O_PUBLIC bit to -define password fields.</p> -</dd> -<dt>O_EDIT</dt> -<dd> -<p>Controls whether the field's data can be modified. When this -option is off, all editing requests except <var class= -"LITERAL">REQ_PREV_CHOICE</var> and <var class= -"LITERAL">REQ_NEXT_CHOICE</var>will fail. Such read-only fields may -be useful for help messages.</p> -</dd> -<dt>O_WRAP</dt> -<dd> -<p>Controls word-wrapping in multi-line fields. Normally, when any -character of a (blank-separated) word reaches the end of the -current line, the entire word is wrapped to the next line (assuming -there is one). When this option is off, the word will be split -across the line break.</p> -</dd> -<dt>O_BLANK</dt> -<dd> -<p>Controls field blanking. When this option is on, entering a -character at the first field position erases the entire field -(except for the just-entered character).</p> -</dd> -<dt>O_AUTOSKIP</dt> -<dd> -<p>Controls automatic skip to next field when this one fills. -Normally, when the forms user tries to type more data into a field -than will fit, the editing location jumps to next field. When this -option is off, the user's cursor will hang at the end of the field. -This option is ignored in dynamic fields that have not reached -their size limit.</p> -</dd> -<dt>O_NULLOK</dt> -<dd> -<p>Controls whether validation is applied to blank fields. -Normally, it is not; the user can leave a field blank without -invoking the usual validation check on exit. If this option is off -on a field, exit from it will invoke a validation check.</p> -</dd> -<dt>O_PASSOK</dt> -<dd> -<p>Controls whether validation occurs on every exit, or only after -the field is modified. Normally the latter is true. Setting -O_PASSOK may be useful if your field's validation function may -change during forms processing.</p> -</dd> -<dt>O_STATIC</dt> -<dd> -<p>Controls whether the field is fixed to its initial dimensions. -If you turn this off, the field becomes dynamic and will stretch to -fit entered data.</p> -</dd> -</dl> -</div> -<p>A field's options cannot be changed while the field is currently -selected. However, options may be changed on posted fields that are -not current.</p> -<p>The option values are bit-masks and can be composed with -logical-or in the obvious way. You have seen the usage of switching -off O_AUTOSKIP option. The following example clarifies usage of -some more options. Other options are explained where -appropriate.</p> -<div class="EXAMPLE"><a name="FFOOP" id="FFOOP"></a> -<p><b>Example 27. Field Options Usage example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <form.h> - -#define STARTX 15 -#define STARTY 4 -#define WIDTH 25 - -#define N_FIELDS 3 - -int main() -{ FIELD *field[N_FIELDS]; - FORM *my_form; - int ch, i; - - /* Initialize curses */ - initscr(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - /* Initialize the fields */ - for(i = 0; i < N_FIELDS - 1; ++i) - field[i] = new_field(1, WIDTH, STARTY + i * 2, STARTX, 0, 0); - field[N_FIELDS - 1] = NULL; - - /* Set field options */ - set_field_back(field[1], A_UNDERLINE); /* Print a line for the option */ - - field_opts_off(field[0], O_ACTIVE); /* This field is a static label */ - field_opts_off(field[1], O_PUBLIC); /* This filed is like a password field*/ - field_opts_off(field[1], O_AUTOSKIP); /* To avoid entering the same field */ - /* after last character is entered */ - - /* Create the form and post it */ - my_form = new_form(field); - post_form(my_form); - refresh(); - - set_field_just(field[0], JUSTIFY_CENTER); /* Center Justification */ - set_field_buffer(field[0], 0, "This is a static Field"); - /* Initialize the field */ - mvprintw(STARTY, STARTX - 10, "Field 1:"); - mvprintw(STARTY + 2, STARTX - 10, "Field 2:"); - refresh(); - - /* Loop through to get user requests */ - while((ch = getch()) != KEY_F(1)) - { switch(ch) - { case KEY_DOWN: - /* Go to next field */ - form_driver(my_form, REQ_NEXT_FIELD); - /* Go to the end of the present buffer */ - /* Leaves nicely at the last character */ - form_driver(my_form, REQ_END_LINE); - break; - case KEY_UP: - /* Go to previous field */ - form_driver(my_form, REQ_PREV_FIELD); - form_driver(my_form, REQ_END_LINE); - break; - default: - /* If this is a normal character, it gets */ - /* Printed */ - form_driver(my_form, ch); - break; - } - } - - /* Un post form and free the memory */ - unpost_form(my_form); - free_form(my_form); - free_field(field[0]); - free_field(field[1]); - - endwin(); - return 0; -}</span></font> -</pre></td> -</tr> -</table> -</div> -<p>This example, though useless, shows the usage of options. If -used properly, they can present information very effectively in a -form. The second field being not O_PUBLIC, does not show the -characters you are typing.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="FIELDSTATUS" id="FIELDSTATUS">18.3.6. -Field Status</a></h4> -<p>The field status specifies whether the field has got edited or -not. It is initially set to FALSE and when user enters something -and the data buffer gets modified it becomes TRUE. So a field's -status can be queried to find out whether it has been modified or -not. The following functions can assist in those operations.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_status(FIELD *field, /* field to alter */ - int status); /* status to set */ - -int field_status(FIELD *field); /* fetch status of field */</font> -</pre></td> -</tr> -</table> -<p>It's better to check the field's status only after after leaving -the field, as data buffer might not have been updated yet as the -validation is still due. To guarantee that right status is -returned, call field_status() either (1) in the field's exit -validation check routine, (2) from the field's or form's -initialization or termination hooks, or (3) just after a -REQ_VALIDATION request has been processed by the forms driver</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="FIELDUSERPTR" id="FIELDUSERPTR">18.3.7. -Field User Pointer</a></h4> -<p>Every field structure contains one pointer that can be used by -the user for various purposes. It is not touched by forms library -and can be used for any purpose by the user. The following -functions set and fetch user pointer.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000">int set_field_userptr(FIELD *field, - char *userptr); /* the user pointer you wish to associate */ - /* with the field */ - -char *field_userptr(FIELD *field); /* fetch user pointer of the field */</font> -</pre></td> -</tr> -</table> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="VARIABLESIZEFIELDS" id= -"VARIABLESIZEFIELDS">18.3.8. Variable-Sized Fields</a></h4> -<p>If you want a dynamically changing field with variable width, -this is the feature you want to put to full use. This will allow -the user to enter more data than the original size of the field and -let the field grow. According to the field orientation it will -scroll horizontally or vertically to incorporate the new data.</p> -<p>To make a field dynamically growable, the option O_STATIC should -be turned off. This can be done with a</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"> field_opts_off(field_pointer, O_STATIC);</font> -</pre></td> -</tr> -</table> -<p>But it's usually not advisable to allow a field to grow -infinitely. You can set a maximum limit to the growth of the field -with</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_max_field(FIELD *field, /* Field on which to operate */ - int max_growth); /* maximum growth allowed for the field */</font> -</pre></td> -</tr> -</table> -<p>The field info for a dynamically growable field can be retrieved -by</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int dynamic_field_info( FIELD *field, /* Field on which to operate */ - int *prows, /* number of rows will be filled in this */ - int *pcols, /* number of columns will be filled in this*/ - int *pmax) /* maximum allowable growth will be filled */ - /* in this */</font> -</pre></td> -</tr> -</table> -Though field_info work as usual, it is advisable to use this -function to get the proper attributes of a dynamically growable -field. -<p>Recall the library routine new_field; a new field created with -height set to one will be defined to be a one line field. A new -field created with height greater than one will be defined to be a -multi line field.</p> -<p>A one line field with O_STATIC turned off (dynamically growable -field) will contain a single fixed row, but the number of columns -can increase if the user enters more data than the initial field -will hold. The number of columns displayed will remain fixed and -the additional data will scroll horizontally.</p> -<p>A multi line field with O_STATIC turned off (dynamically -growable field) will contain a fixed number of columns, but the -number of rows can increase if the user enters more data than the -initial field will hold. The number of rows displayed will remain -fixed and the additional data will scroll vertically.</p> -<p>The above two paragraphs pretty much describe a dynamically -growable field's behavior. The way other parts of forms library -behaves is described below:</p> -<ol type="1"> -<li> -<p>The field option O_AUTOSKIP will be ignored if the option -O_STATIC is off and there is no maximum growth specified for the -field. Currently, O_AUTOSKIP generates an automatic REQ_NEXT_FIELD -form driver request when the user types in the last character -position of a field. On a growable field with no maximum growth -specified, there is no last character position. If a maximum growth -is specified, the O_AUTOSKIP option will work as normal if the -field has grown to its maximum size.</p> -</li> -<li> -<p>The field justification will be ignored if the option O_STATIC -is off. Currently, set_field_just can be used to JUSTIFY_LEFT, -JUSTIFY_RIGHT, JUSTIFY_CENTER the contents of a one line field. A -growable one line field will, by definition, grow and scroll -horizontally and may contain more data than can be justified. The -return from field_just will be unchanged.</p> -</li> -<li> -<p>The overloaded form driver request REQ_NEW_LINE will operate the -same way regardless of the O_NL_OVERLOAD form option if the field -option O_STATIC is off and there is no maximum growth specified for -the field. Currently, if the form option O_NL_OVERLOAD is on, -REQ_NEW_LINE implicitly generates a REQ_NEXT_FIELD if called from -the last line of a field. If a field can grow without bound, there -is no last line, so REQ_NEW_LINE will never implicitly generate a -REQ_NEXT_FIELD. If a maximum growth limit is specified and the -O_NL_OVERLOAD form option is on, REQ_NEW_LINE will only implicitly -generate REQ_NEXT_FIELD if the field has grown to its maximum size -and the user is on the last line.</p> -</li> -<li> -<p>The library call dup_field will work as usual; it will duplicate -the field, including the current buffer size and contents of the -field being duplicated. Any specified maximum growth will also be -duplicated.</p> -</li> -<li> -<p>The library call link_field will work as usual; it will -duplicate all field attributes and share buffers with the field -being linked. If the O_STATIC field option is subsequently changed -by a field sharing buffers, how the system reacts to an attempt to -enter more data into the field than the buffer will currently hold -will depend on the setting of the option in the current field.</p> -</li> -<li> -<p>The library call field_info will work as usual; the variable -nrow will contain the value of the original call to new_field. The -user should use dynamic_field_info, described above, to query the -current size of the buffer.</p> -</li> -</ol> -<p>Some of the above points make sense only after explaining form -driver. We will be looking into that in next few sections.</p> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="FORMWINDOWS" id="FORMWINDOWS">18.4. Form -Windows</a></h3> -<p>The form windows concept is pretty much similar to menu windows. -Every form is associated with a main window and a sub window. The -form main window displays any title or border associated or -whatever the user wishes. Then the sub window contains all the -fields and displays them according to their position. This gives -the flexibility of manipulating fancy form displaying very -easily.</p> -<p>Since this is pretty much similar to menu windows, I am -providing an example with out much explanation. The functions are -similar and they work the same way.</p> -<div class="EXAMPLE"><a name="FFOWI" id="FFOWI"></a> -<p><b>Example 28. Form Windows Example</b></p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000"><span class= -"INLINEMEDIAOBJECT">#include <form.h> - -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); - -int main() -{ - FIELD *field[3]; - FORM *my_form; - WINDOW *my_form_win; - int ch, rows, cols; - - /* Initialize curses */ - initscr(); - start_color(); - cbreak(); - noecho(); - keypad(stdscr, TRUE); - - /* Initialize few color pairs */ - init_pair(1, COLOR_RED, COLOR_BLACK); - - /* Initialize the fields */ - field[0] = new_field(1, 10, 6, 1, 0, 0); - field[1] = new_field(1, 10, 8, 1, 0, 0); - field[2] = NULL; - - /* Set field options */ - set_field_back(field[0], A_UNDERLINE); - field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ - /* Field is filled up */ - set_field_back(field[1], A_UNDERLINE); - field_opts_off(field[1], O_AUTOSKIP); - - /* Create the form and post it */ - my_form = new_form(field); - - /* Calculate the area required for the form */ - scale_form(my_form, &rows, &cols); - - /* Create the window to be associated with the form */ - my_form_win = newwin(rows + 4, cols + 4, 4, 4); - keypad(my_form_win, TRUE); - - /* Set main window and sub window */ - set_form_win(my_form, my_form_win); - set_form_sub(my_form, derwin(my_form_win, rows, cols, 2, 2)); - - /* Print a border around the main window and print a title */ - box(my_form_win, 0, 0); - print_in_middle(my_form_win, 1, 0, cols + 4, "My Form", COLOR_PAIR(1)); - - post_form(my_form); - wrefresh(my_form_win); - - mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields"); - refresh(); - - /* Loop through to get user requests */ - while((ch = wgetch(my_form_win)) != KEY_F(1)) - { switch(ch) - { case KEY_DOWN: - /* Go to next field */ - form_driver(my_form, REQ_NEXT_FIELD); - /* Go to the end of the present buffer */ - /* Leaves nicely at the last character */ - form_driver(my_form, REQ_END_LINE); - break; - case KEY_UP: - /* Go to previous field */ - form_driver(my_form, REQ_PREV_FIELD); - form_driver(my_form, REQ_END_LINE); - break; - default: - /* If this is a normal character, it gets */ - /* Printed */ - form_driver(my_form, ch); - break; - } - } - - /* Un post form and free the memory */ - unpost_form(my_form); - free_form(my_form); - free_field(field[0]); - free_field(field[1]); - - endwin(); - return 0; -} - -void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) -{ int length, x, y; - float temp; - - if(win == NULL) - win = stdscr; - getyx(win, y, x); - if(startx != 0) - x = startx; - if(starty != 0) - y = starty; - if(width == 0) - width = 80; - - length = strlen(string); - temp = (width - length)/ 2; - x = startx + (int)temp; - wattron(win, color); - mvwprintw(win, y, x, "%s", string); - wattroff(win, color); - refresh(); -}</span></font> -</pre></td> -</tr> -</table> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="FILEDVALIDATE" id="FILEDVALIDATE">18.5. -Field Validation</a></h3> -<p>By default, a field will accept any data input by the user. It -is possible to attach validation to the field. Then any attempt by -the user to leave the field, while it contains data that doesn't -match the validation type will fail. Some validation types also -have a character-validity check for each time a character is -entered in the field.</p> -<p>Validation can be attached to a field with the following -function.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_type(FIELD *field, /* field to alter */ - FIELDTYPE *ftype, /* type to associate */ - ...); /* additional arguments*/</font> -</pre></td> -</tr> -</table> -Once set, the validation type for a field can be queried with -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">FIELDTYPE *field_type(FIELD *field); /* field to query */</font> -</pre></td> -</tr> -</table> -<p>The form driver validates the data in a field only when data is -entered by the end-user. Validation does not occur when</p> -<ul> -<li> -<p>the application program changes the field value by calling -set_field_buffer.</p> -</li> -<li> -<p>linked field values are changed indirectly -- by changing the -field to which they are linked</p> -</li> -</ul> -<p>The following are the pre-defined validation types. You can also -specify custom validation, though it's a bit tricky and -cumbersome.</p> -<h1 class="BRIDGEHEAD"><a name="AEN1069" id= -"AEN1069"></a>TYPE_ALPHA</h1> -<p>This field type accepts alphabetic data; no blanks, no digits, -no special characters (this is checked at character-entry time). It -is set up with:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_type(FIELD *field, /* field to alter */ - TYPE_ALPHA, /* type to associate */ - int width); /* maximum width of field */</font> -</pre></td> -</tr> -</table> -<p>The width argument sets a minimum width of data. The user has to -enter at-least width number of characters before he can leave the -field. Typically you'll want to set this to the field width; if -it's greater than the field width, the validation check will always -fail. A minimum width of zero makes field completion optional.</p> -<h1 class="BRIDGEHEAD"><a name="AEN1073" id= -"AEN1073"></a>TYPE_ALNUM</h1> -<p>This field type accepts alphabetic data and digits; no blanks, -no special characters (this is checked at character-entry time). It -is set up with:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_type(FIELD *field, /* field to alter */ - TYPE_ALNUM, /* type to associate */ - int width); /* maximum width of field */</font> -</pre></td> -</tr> -</table> -<p>The width argument sets a minimum width of data. As with -TYPE_ALPHA, typically you'll want to set this to the field width; -if it's greater than the field width, the validation check will -always fail. A minimum width of zero makes field completion -optional.</p> -<h1 class="BRIDGEHEAD"><a name="AEN1077" id= -"AEN1077"></a>TYPE_ENUM</h1> -<p>This type allows you to restrict a field's values to be among a -specified set of string values (for example, the two-letter postal -codes for U.S. states). It is set up with:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_type(FIELD *field, /* field to alter */ - TYPE_ENUM, /* type to associate */ - char **valuelist; /* list of possible values */ - int checkcase; /* case-sensitive? */ - int checkunique); /* must specify uniquely? */</font> -</pre></td> -</tr> -</table> -<p>The valuelist parameter must point at a NULL-terminated list of -valid strings. The checkcase argument, if true, makes comparison -with the string case-sensitive.</p> -<p>When the user exits a TYPE_ENUM field, the validation procedure -tries to complete the data in the buffer to a valid entry. If a -complete choice string has been entered, it is of course valid. But -it is also possible to enter a prefix of a valid string and have it -completed for you.</p> -<p>By default, if you enter such a prefix and it matches more than -one value in the string list, the prefix will be completed to the -first matching value. But the checkunique argument, if true, -requires prefix matches to be unique in order to be valid.</p> -<p>The REQ_NEXT_CHOICE and REQ_PREV_CHOICE input requests can be -particularly useful with these fields.</p> -<h1 class="BRIDGEHEAD"><a name="AEN1084" id= -"AEN1084"></a>TYPE_INTEGER</h1> -<p>This field type accepts an integer. It is set up as follows:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_type(FIELD *field, /* field to alter */ - TYPE_INTEGER, /* type to associate */ - int padding, /* # places to zero-pad to */ - int vmin, int vmax); /* valid range */</font> -</pre></td> -</tr> -</table> -<p>Valid characters consist of an optional leading minus and -digits. The range check is performed on exit. If the range maximum -is less than or equal to the minimum, the range is ignored.</p> -<p>If the value passes its range check, it is padded with as many -leading zero digits as necessary to meet the padding argument.</p> -<p>A TYPE_INTEGER value buffer can conveniently be interpreted with -the C library function atoi(3).</p> -<h1 class="BRIDGEHEAD"><a name="AEN1090" id= -"AEN1090"></a>TYPE_NUMERIC</h1> -<p>This field type accepts a decimal number. It is set up as -follows:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_type(FIELD *field, /* field to alter */ - TYPE_NUMERIC, /* type to associate */ - int padding, /* # places of precision */ - int vmin, int vmax); /* valid range */</font> -</pre></td> -</tr> -</table> -<p>Valid characters consist of an optional leading minus and -digits. possibly including a decimal point. The range check is -performed on exit. If the range maximum is less than or equal to -the minimum, the range is ignored.</p> -<p>If the value passes its range check, it is padded with as many -trailing zero digits as necessary to meet the padding argument.</p> -<p>A TYPE_NUMERIC value buffer can conveniently be interpreted with -the C library function atof(3).</p> -<h1 class="BRIDGEHEAD"><a name="AEN1096" id= -"AEN1096"></a>TYPE_REGEXP</h1> -<p>This field type accepts data matching a regular expression. It -is set up as follows:</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_field_type(FIELD *field, /* field to alter */ - TYPE_REGEXP, /* type to associate */ - char *regexp); /* expression to match */</font> -</pre></td> -</tr> -</table> -<p>The syntax for regular expressions is that of regcomp(3). The -check for regular-expression match is performed on exit.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="FORMDRIVER" id="FORMDRIVER">18.6. Form -Driver: The work horse of the forms system</a></h3> -<p>As in the menu system, form_driver() plays a very important role -in forms system. All types of requests to forms system should be -funneled through form_driver().</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int form_driver(FORM *form, /* form on which to operate */ - int request) /* form request code */</font> -</pre></td> -</tr> -</table> -<p>As you have seen some of the examples above, you have to be in a -loop looking for user input and then decide whether it's a field -data or a form request. The form requests are then passed to -form_driver() to do the work.</p> -<p>The requests roughly can be divided into following categories. -Different requests and their usage is explained below:</p> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="PAGENAVREQ" id="PAGENAVREQ">18.6.1. Page -Navigation Requests</a></h4> -<p>These requests cause page-level moves through the form, -triggering display of a new form screen. A form can be made of -multiple pages. If you have a big form with lot of fields and -logical sections, then you can divide the form into pages. The -function set_new_page() to set a new page at the field -specified.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">int set_new_page(FIELD *field,/* Field at which page break to be set or unset */ - bool new_page_flag); /* should be TRUE to put a break */</font> -</pre></td> -</tr> -</table> -<p>The following requests allow you to move to different pages</p> -<ul> -<li> -<p><em>REQ_NEXT_PAGE</em> Move to the next form page.</p> -</li> -<li> -<p><em>REQ_PREV_PAGE</em> Move to the previous form page.</p> -</li> -<li> -<p><em>REQ_FIRST_PAGE</em> Move to the first form page.</p> -</li> -<li> -<p><em>REQ_LAST_PAGE</em> Move to the last form page.</p> -</li> -</ul> -<p>These requests treat the list as cyclic; that is, REQ_NEXT_PAGE -from the last page goes to the first, and REQ_PREV_PAGE from the -first page goes to the last.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="INTERFIELDNAVREQ" id= -"INTERFIELDNAVREQ">18.6.2. Inter-Field Navigation Requests</a></h4> -<p>These requests handle navigation between fields on the same -page.</p> -<ul> -<li> -<p><em>REQ_NEXT_FIELD</em> Move to next field.</p> -</li> -<li> -<p><em>REQ_PREV_FIELD</em> Move to previous field.</p> -</li> -<li> -<p><em>REQ_FIRST_FIELD</em> Move to the first field.</p> -</li> -<li> -<p><em>REQ_LAST_FIELD</em> Move to the last field.</p> -</li> -<li> -<p><em>REQ_SNEXT_FIELD</em> Move to sorted next field.</p> -</li> -<li> -<p><em>REQ_SPREV_FIELD</em> Move to sorted previous field.</p> -</li> -<li> -<p><em>REQ_SFIRST_FIELD</em> Move to the sorted first field.</p> -</li> -<li> -<p><em>REQ_SLAST_FIELD</em> Move to the sorted last field.</p> -</li> -<li> -<p><em>REQ_LEFT_FIELD</em> Move left to field.</p> -</li> -<li> -<p><em>REQ_RIGHT_FIELD</em> Move right to field.</p> -</li> -<li> -<p><em>REQ_UP_FIELD</em> Move up to field.</p> -</li> -<li> -<p><em>REQ_DOWN_FIELD</em> Move down to field.</p> -</li> -</ul> -<p>These requests treat the list of fields on a page as cyclic; -that is, REQ_NEXT_FIELD from the last field goes to the first, and -REQ_PREV_FIELD from the first field goes to the last. The order of -the fields for these (and the REQ_FIRST_FIELD and REQ_LAST_FIELD -requests) is simply the order of the field pointers in the form -array (as set up by new_form() or set_form_fields()</p> -<p>It is also possible to traverse the fields as if they had been -sorted in screen-position order, so the sequence goes left-to-right -and top-to-bottom. To do this, use the second group of four -sorted-movement requests.</p> -<p>Finally, it is possible to move between fields using visual -directions up, down, right, and left. To accomplish this, use the -third group of four requests. Note, however, that the position of a -form for purposes of these requests is its upper-left corner.</p> -<p>For example, suppose you have a multi-line field B, and two -single-line fields A and C on the same line with B, with A to the -left of B and C to the right of B. A REQ_MOVE_RIGHT from A will go -to B only if A, B, and C all share the same first line; otherwise -it will skip over B to C.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="INTRAFIELDNAVREQ" id= -"INTRAFIELDNAVREQ">18.6.3. Intra-Field Navigation Requests</a></h4> -<p>These requests drive movement of the edit cursor within the -currently selected field.</p> -<ul> -<li> -<p><em>REQ_NEXT_CHAR</em> Move to next character.</p> -</li> -<li> -<p><em>REQ_PREV_CHAR</em> Move to previous character.</p> -</li> -<li> -<p><em>REQ_NEXT_LINE</em> Move to next line.</p> -</li> -<li> -<p><em>REQ_PREV_LINE</em> Move to previous line.</p> -</li> -<li> -<p><em>REQ_NEXT_WORD</em> Move to next word.</p> -</li> -<li> -<p><em>REQ_PREV_WORD</em> Move to previous word.</p> -</li> -<li> -<p><em>REQ_BEG_FIELD</em> Move to beginning of field.</p> -</li> -<li> -<p><em>REQ_END_FIELD</em> Move to end of field.</p> -</li> -<li> -<p><em>REQ_BEG_LINE</em> Move to beginning of line.</p> -</li> -<li> -<p><em>REQ_END_LINE</em> Move to end of line.</p> -</li> -<li> -<p><em>REQ_LEFT_CHAR</em> Move left in field.</p> -</li> -<li> -<p><em>REQ_RIGHT_CHAR</em> Move right in field.</p> -</li> -<li> -<p><em>REQ_UP_CHAR</em> Move up in field.</p> -</li> -<li> -<p><em>REQ_DOWN_CHAR</em> Move down in field.</p> -</li> -</ul> -<p>Each word is separated from the previous and next characters by -whitespace. The commands to move to beginning and end of line or -field look for the first or last non-pad character in their -ranges.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="SCROLLREQ" id="SCROLLREQ">18.6.4. -Scrolling Requests</a></h4> -<p>Fields that are dynamic and have grown and fields explicitly -created with offscreen rows are scrollable. One-line fields scroll -horizontally; multi-line fields scroll vertically. Most scrolling -is triggered by editing and intra-field movement (the library -scrolls the field to keep the cursor visible). It is possible to -explicitly request scrolling with the following requests:</p> -<ul> -<li> -<p><em>REQ_SCR_FLINE</em> Scroll vertically forward a line.</p> -</li> -<li> -<p><em>REQ_SCR_BLINE</em> Scroll vertically backward a line.</p> -</li> -<li> -<p><em>REQ_SCR_FPAGE</em> Scroll vertically forward a page.</p> -</li> -<li> -<p><em>REQ_SCR_BPAGE</em> Scroll vertically backward a page.</p> -</li> -<li> -<p><em>REQ_SCR_FHPAGE</em> Scroll vertically forward half a -page.</p> -</li> -<li> -<p><em>REQ_SCR_BHPAGE</em> Scroll vertically backward half a -page.</p> -</li> -<li> -<p><em>REQ_SCR_FCHAR</em> Scroll horizontally forward a -character.</p> -</li> -<li> -<p><em>REQ_SCR_BCHAR</em> Scroll horizontally backward a -character.</p> -</li> -<li> -<p><em>REQ_SCR_HFLINE</em> Scroll horizontally one field width -forward.</p> -</li> -<li> -<p><em>REQ_SCR_HBLINE</em> Scroll horizontally one field width -backward.</p> -</li> -<li> -<p><em>REQ_SCR_HFHALF</em> Scroll horizontally one half field width -forward.</p> -</li> -<li> -<p><em>REQ_SCR_HBHALF</em> Scroll horizontally one half field width -backward.</p> -</li> -</ul> -<p>For scrolling purposes, a page of a field is the height of its -visible part.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="EDITREQ" id="EDITREQ">18.6.5. Editing -Requests</a></h4> -<p>When you pass the forms driver an ASCII character, it is treated -as a request to add the character to the field's data buffer. -Whether this is an insertion or a replacement depends on the -field's edit mode (insertion is the default.</p> -<p>The following requests support editing the field and changing -the edit mode:</p> -<ul> -<li> -<p><em>REQ_INS_MODE</em> Set insertion mode.</p> -</li> -<li> -<p><em>REQ_OVL_MODE</em> Set overlay mode.</p> -</li> -<li> -<p><em>REQ_NEW_LINE</em> New line request (see below for -explanation).</p> -</li> -<li> -<p><em>REQ_INS_CHAR</em> Insert space at character location.</p> -</li> -<li> -<p><em>REQ_INS_LINE</em> Insert blank line at character -location.</p> -</li> -<li> -<p><em>REQ_DEL_CHAR</em> Delete character at cursor.</p> -</li> -<li> -<p><em>REQ_DEL_PREV</em> Delete previous word at cursor.</p> -</li> -<li> -<p><em>REQ_DEL_LINE</em> Delete line at cursor.</p> -</li> -<li> -<p><em>REQ_DEL_WORD</em> Delete word at cursor.</p> -</li> -<li> -<p><em>REQ_CLR_EOL</em> Clear to end of line.</p> -</li> -<li> -<p><em>REQ_CLR_EOF</em> Clear to end of field.</p> -</li> -<li> -<p><em>REQ_CLR_FIELD</em> Clear entire field.</p> -</li> -</ul> -<p>The behavior of the REQ_NEW_LINE and REQ_DEL_PREV requests is -complicated and partly controlled by a pair of forms options. The -special cases are triggered when the cursor is at the beginning of -a field, or on the last line of the field.</p> -<p>First, we consider REQ_NEW_LINE:</p> -<p>The normal behavior of REQ_NEW_LINE in insert mode is to break -the current line at the position of the edit cursor, inserting the -portion of the current line after the cursor as a new line -following the current and moving the cursor to the beginning of -that new line (you may think of this as inserting a newline in the -field buffer).</p> -<p>The normal behavior of REQ_NEW_LINE in overlay mode is to clear -the current line from the position of the edit cursor to end of -line. The cursor is then moved to the beginning of the next -line.</p> -<p>However, REQ_NEW_LINE at the beginning of a field, or on the -last line of a field, instead does a REQ_NEXT_FIELD. O_NL_OVERLOAD -option is off, this special action is disabled.</p> -<p>Now, let us consider REQ_DEL_PREV:</p> -<p>The normal behavior of REQ_DEL_PREV is to delete the previous -character. If insert mode is on, and the cursor is at the start of -a line, and the text on that line will fit on the previous one, it -instead appends the contents of the current line to the previous -one and deletes the current line (you may think of this as deleting -a newline from the field buffer).</p> -<p>However, REQ_DEL_PREV at the beginning of a field is instead -treated as a REQ_PREV_FIELD.</p> -<p>If the O_BS_OVERLOAD option is off, this special action is -disabled and the forms driver just returns E_REQUEST_DENIED.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="ORDERREQ" id="ORDERREQ">18.6.6. Order -Requests</a></h4> -<p>If the type of your field is ordered, and has associated -functions for getting the next and previous values of the type from -a given value, there are requests that can fetch that value into -the field buffer:</p> -<ul> -<li> -<p><em>REQ_NEXT_CHOICE</em> Place the successor value of the -current value in the buffer.</p> -</li> -<li> -<p><em>REQ_PREV_CHOICE</em> Place the predecessor value of the -current value in the buffer.</p> -</li> -</ul> -<p>Of the built-in field types, only TYPE_ENUM has built-in -successor and predecessor functions. When you define a field type -of your own (see Custom Validation Types), you can associate our -own ordering functions.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="APPLICCOMMANDS" id= -"APPLICCOMMANDS">18.6.7. Application Commands</a></h4> -<p>Form requests are represented as integers above the curses value -greater than KEY_MAX and less than or equal to the constant -MAX_COMMAND. A value within this range gets ignored by -form_driver(). So this can be used for any purpose by the -application. It can be treated as an application specific action -and take corresponding action.</p> -</div> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="TOOLS" id="TOOLS">19. Tools and Widget -Libraries</a></h2> -<p>Now that you have seen the capabilities of ncurses and its -sister libraries, you are rolling your sleeves up and gearing for a -project that heavily manipulates screen. But wait.. It can be -pretty difficult to write and maintain complex GUI widgets in plain -ncurses or even with the additional libraries. There are some -ready-to-use tools and widget libraries that can be used instead of -writing your own widgets. You can use some of them, get ideas from -the code, or even extend them.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="CDK" id="CDK">19.1. CDK (Curses -Development Kit)</a></h3> -<p>In the author's words</p> -<p><em>CDK stands for 'Curses Development Kit' and it currently -contains 21 ready to use widgets which facilitate the speedy -development of full screen curses programs.</em></p> -<p>The kit provides some useful widgets, which can be used in your -programs directly. It's pretty well written and the documentation -is very good. The examples in the examples directory can be a good -place to start for beginners. The CDK can be downloaded from -<a href="http://invisible-island.net/cdk/" target= -"_top">http://invisible-island.net/cdk/</a> . Follow the -instructions in README file to install it.</p> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="WIDGETLIST" id="WIDGETLIST">19.1.1. -Widget List</a></h4> -<p>The following is the list of widgets provided with cdk and their -description.</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color="#000000">Widget Type Quick Description -=========================================================================== -Alphalist Allows a user to select from a list of words, with - the ability to narrow the search list by typing in a - few characters of the desired word. -Buttonbox This creates a multiple button widget. -Calendar Creates a little simple calendar widget. -Dialog Prompts the user with a message, and the user - can pick an answer from the buttons provided. -Entry Allows the user to enter various types of information. -File Selector A file selector built from Cdk base widgets. This - example shows how to create more complicated widgets - using the Cdk widget library. -Graph Draws a graph. -Histogram Draws a histogram. -Item List Creates a pop up field which allows the user to select - one of several choices in a small field. Very useful - for things like days of the week or month names. -Label Displays messages in a pop up box, or the label can be - considered part of the screen. -Marquee Displays a message in a scrolling marquee. -Matrix Creates a complex matrix with lots of options. -Menu Creates a pull-down menu interface. -Multiple Line Entry A multiple line entry field. Very useful - for long fields. (like a description - field) -Radio List Creates a radio button list. -Scale Creates a numeric scale. Used for allowing a user to - pick a numeric value and restrict them to a range of - values. -Scrolling List Creates a scrolling list/menu list. -Scrolling Window Creates a scrolling log file viewer. Can add - information into the window while its running. - A good widget for displaying the progress of - something. (akin to a console window) -Selection List Creates a multiple option selection list. -Slider Akin to the scale widget, this widget provides a - visual slide bar to represent the numeric value. -Template Creates a entry field with character sensitive - positions. Used for pre-formatted fields like - dates and phone numbers. -Viewer This is a file/information viewer. Very useful - when you need to display loads of information. -===========================================================================</font> -</pre></td> -</tr> -</table> -<p>A few of the widgets are modified by Thomas Dickey in recent -versions.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="CDKATTRACT" id="CDKATTRACT">19.1.2. Some -Attractive Features</a></h4> -<p>Apart from making our life easier with readily usable widgets, -cdk solves one frustrating problem with printing multi colored -strings, justified strings elegantly. Special formatting tags can -be embedded in the strings which are passed to CDK functions. For -Example</p> -<p>If the string</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000">"</B/1>This line should have a yellow foreground and a blue -background.<!1>"</font> -</pre></td> -</tr> -</table> -<p>given as a parameter to newCDKLabel(), it prints the line with -yellow foreground and blue background. There are other tags -available for justifying string, embedding special drawing -characters etc.. Please refer to the man page cdk_display(3X) for -details. The man page explains the usage with nice examples.</p> -</div> -<div class="SECT3"> -<hr> -<h4 class="SECT3"><a name="CDKCONCLUSION" id= -"CDKCONCLUSION">19.1.3. Conclusion</a></h4> -<p>All in all, CDK is a well-written package of widgets, which if -used properly can form a strong frame work for developing complex -GUI.</p> -</div> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="DIALOG" id="DIALOG">19.2. The -dialog</a></h3> -<p>Long long ago, in September 1994, when few people knew linux, -Jeff Tranter wrote an <a href= -"http://www2.linuxjournal.com/lj-issues/issue5/2807.html" target= -"_top">article</a> on dialog in Linux Journal. He starts the -article with these words..</p> -<p><em>Linux is based on the Unix operating system, but also -features a number of unique and useful kernel features and -application programs that often go beyond what is available under -Unix. One little-known gem is "dialog", a utility for creating -professional-looking dialog boxes from within shell scripts. This -article presents a tutorial introduction to the dialog utility, and -shows examples of how and where it can be used</em></p> -<p>As he explains, dialog is a real gem in making -professional-looking dialog boxes with ease. It creates a variety -of dialog boxes, menus, check lists etc.. It is usually installed -by default. If not, you can download it from <a href= -"http://invisible-island.net/dialog/" target="_top">Thomas -Dickey</a>'s site.</p> -<p>The above-mentioned article gives a very good overview of its -uses and capabilites. The man page has more details. It can be used -in variety of situations. One good example is building of linux -kernel in text mode. Linux kernel uses a modified version of dialog -tailored for its needs.</p> -<p>dialog was initially designed to be used with shell scripts. If -you want to use its functionality in a c program, then you can use -libdialog. The documentation regarding this is sparse. Definitive -reference is the dialog.h header file which comes with the library. -You may need to hack here and there to get the required output. The -source is easily customizable. I have used it on a number of -occasions by modifying the code.</p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="PERLCURSES" id="PERLCURSES">19.3. Perl -Curses Modules CURSES::FORM and CURSES::WIDGETS</a></h3> -<p>The perl module Curses, Curses::Form and Curses::Widgets give -access to curses from perl. If you have curses and basic perl is -installed, you can get these modules from <a href= -"http://www.cpan.org/modules/01modules.index.html" target= -"_top">CPAN All Modules page</a>. Get the three zipped modules in -the Curses category. Once installed you can use these modules from -perl scripts like any other module. For more information on perl -modules see perlmod man page. The above modules come with good -documentation and they have some demo scripts to test the -functionality. Though the widgets provided are very rudimentary, -these modules provide good access to curses library from perl.</p> -<p>Some of my code examples are converted to perl by Anuradha -Ratnaweera and they are available in the <var class= -"LITERAL">perl</var> directory.</p> -<p>For more information see man pages Curses(3) , Curses::Form(3) -and Curses::Widgets(3). These pages are installed only when the -above modules are acquired and installed.</p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="JUSTFORFUN" id="JUSTFORFUN">20. Just For -Fun !!!</a></h2> -<p>This section contains few programs written by me just for fun. -They don't signify a better programming practice or the best way of -using ncurses. They are provided here so as to allow beginners to -get ideas and add more programs to this section. If you have -written a couple of nice, simple programs in curses and want them -to included here, contact <a href="mailto:ppadala@gmail.com" -target="_top">me</a>.</p> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="GAMEOFLIFE" id="GAMEOFLIFE">20.1. The -Game of Life</a></h3> -<p>Game of life is a wonder of math. In <a href= -"http://www.math.com/students/wonders/life/life.html" target= -"_top">Paul Callahan</a>'s words</p> -<table border="0" bgcolor="#E0E0E0" width="100%"> -<tr> -<td> -<pre class="PROGRAMLISTING"> -<font color= -"#000000"><em>The Game of Life (or simply Life) is not a game in the conventional sense. There -are no players, and no winning or losing. Once the "pieces" are placed in the -starting position, the rules determine everything that happens later. -Nevertheless, Life is full of surprises! In most cases, it is impossible to look -at a starting position (or pattern) and see what will happen in the future. The -only way to find out is to follow the rules of the game.</em></font> -</pre></td> -</tr> -</table> -<p>This program starts with a simple inverted U pattern and shows -how wonderful life works. There is a lot of room for improvement in -the program. You can let the user enter pattern of his choice or -even take input from a file. You can also change rules and play -with a lot of variations. Search on <a href="http://www.google.com" -target="_top">google</a> for interesting information on game of -life.</p> -<p><em>File Path: JustForFun/life.c</em></p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="MAGIC" id="MAGIC">20.2. Magic -Square</a></h3> -<p>Magic Square, another wonder of math, is very simple to -understand but very difficult to make. In a magic square sum of the -numbers in each row, each column is equal. Even diagnol sum can be -equal. There are many variations which have special properties.</p> -<p>This program creates a simple magic square of odd order.</p> -<p><em>File Path: JustForFun/magic.c</em></p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="HANOI" id="HANOI">20.3. Towers of -Hanoi</a></h3> -<p>The famous towers of hanoi solver. The aim of the game is to -move the disks on the first peg to last peg, using middle peg as a -temporary stay. The catch is not to place a larger disk over a -small disk at any time.</p> -<p><em>File Path: JustForFun/hanoi.c</em></p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="QUEENS" id="QUEENS">20.4. Queens -Puzzle</a></h3> -<p>The objective of the famous N-Queen puzzle is to put N queens on -a N X N chess board without attacking each other.</p> -<p>This program solves it with a simple backtracking technique.</p> -<p><em>File Path: JustForFun/queens.c</em></p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="SHUFFLE" id="SHUFFLE">20.5. -Shuffle</a></h3> -<p>A fun game, if you have time to kill.</p> -<p><em>File Path: JustForFun/shuffle.c</em></p> -</div> -<div class="SECT2"> -<hr> -<h3 class="SECT2"><a name="TT" id="TT">20.6. Typing Tutor</a></h3> -<p>A simple typing tutor, I created more out of need than for ease -of use. If you know how to put your fingers correctly on the -keyboard, but lack practice, this can be helpful.</p> -<p><em>File Path: JustForFun/tt.c</em></p> -</div> -</div> -<div class="SECT1"> -<hr> -<h2 class="SECT1"><a name="REF" id="REF">21. References</a></h2> -<ul> -<li> -<p>NCURSES man pages</p> -</li> -<li> -<p>NCURSES FAQ at <a href= -"http://invisible-island.net/ncurses/ncurses.faq.html" target= -"_top">http://invisible-island.net/ncurses/ncurses.faq.html</a></p> -</li> -<li> -<p>Writing programs with NCURSES by Eric Raymond and Zeyd M. -Ben-Halim at <a href= -"http://invisible-island.net/ncurses/ncurses-intro.html" target= -"_top">http://invisible-island.net/ncurses/ncurses-intro.html</a> - -somewhat obsolete. I was inspired by this document and the -structure of this HOWTO follows from the original document</p> -</li> -</ul> -</div> -</div> -</body> -</html> |