aboutsummaryrefslogtreecommitdiff
path: root/doc/html/man/default_colors.3x.html
blob: c91d0119598baba05d9856c9dc6d2599ce7007cf (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
<!-- 
  ****************************************************************************
  * Copyright (c) 1998-2018,2019 Free Software Foundation, Inc.              *
  *                                                                          *
  * 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:                 *
  *                                                                          *
  * The above copyright notice and this permission notice shall be included  *
  * in all copies or substantial portions of the Software.                   *
  *                                                                          *
  * 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.                               *
  *                                                                          *
  * 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.                                                           *
  ****************************************************************************
  * Author: Thomas E. Dickey 1997,1999,2000,2005
  * @Id: default_colors.3x,v 1.28 2019/11/30 21:06:30 tom Exp @
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="generator" content="Manpage converted by man2html - see https://invisible-island.net/scripts/readme.html#others_scripts">
<TITLE>default_colors 3x</TITLE>
<link rel="author" href="mailto:bug-ncurses@gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</HEAD>
<BODY>
<H1 class="no-header">default_colors 3x</H1>
<PRE>
<STRONG><A HREF="default_colors.3x.html">default_colors(3x)</A></STRONG>                                          <STRONG><A HREF="default_colors.3x.html">default_colors(3x)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>use_default_colors</STRONG>, <STRONG>assume_default_colors</STRONG> - use terminal's default col-
       ors


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>

       <STRONG>int</STRONG> <STRONG>use_default_colors(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>assume_default_colors(int</STRONG> <STRONG>fg,</STRONG> <STRONG>int</STRONG> <STRONG>bg);</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
       The <STRONG>use_default_colors</STRONG> and <STRONG>assume_default_colors</STRONG> functions  are  exten-
       sions to the curses library.  They are used with terminals that support
       ISO 6429 color, or equivalent.  These terminals allow  the  application
       to  reset  color  to an unspecified default value (e.g., with SGR 39 or
       SGR 49).

       Applications that paint a colored background over the whole  screen  do
       not  take  advantage  of  SGR  39  and  SGR  49.  Some applications are
       designed to work with the default background,  using  colors  only  for
       text.  For example, there are several implementations of the <STRONG>ls</STRONG> program
       which use colors to denote different file types or permissions.   These
       "color  ls"  programs  do  not necessarily modify the background color,
       typically using only the <STRONG>setaf</STRONG> terminfo capability  to  set  the  fore-
       ground  color.   Full-screen  applications  that use default colors can
       achieve similar visual effects.

       The first function, <STRONG>use_default_colors</STRONG>  tells  the  curses  library  to
       assign  terminal  default  foreground/background colors to color number
       -1.  So init_pair(x,COLOR_RED,-1) will initialize  pair  x  as  red  on
       default  background and init_pair(x,-1,COLOR_BLUE) will initialize pair
       x as default foreground on blue.

       The other, <STRONG>assume_default_colors</STRONG> is a refinement which tells which col-
       ors  to  paint  for  color  pair 0.  This function recognizes a special
       color number -1, which denotes the default terminal color.

       The following are equivalent:
              <EM>use</EM><STRONG>_</STRONG><EM>default</EM><STRONG>_</STRONG><EM>colors();</EM>
              <EM>assume</EM><STRONG>_</STRONG><EM>default</EM><STRONG>_</STRONG><EM>colors(-1,-1);</EM>

       These are ncurses extensions.  For other curses implementations,  color
       number -1 does not mean anything, just as for ncurses before a success-
       ful call of <STRONG>use_default_colors</STRONG> or <STRONG>assume_default_colors</STRONG>.

       Other curses implementations do not  allow  an  application  to  modify
       color  pair  0.  They assume that the background is COLOR_BLACK, but do
       not ensure that the color pair 0 is painted to  match  the  assumption.
       If   your   application  does  not  use  either  <STRONG>use_default_colors</STRONG>  or
       <STRONG>assume_default_colors</STRONG> ncurses will paint a white foreground (text) with
       black background for color pair 0.


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       These  functions return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on success.
       They will fail if either the terminal does not support the <STRONG>orig_pair</STRONG> or
       <STRONG>orig_colors</STRONG>  capability.   If  the  <STRONG>initialize_pair</STRONG>  capability  is not
       found, this causes an error as well.


</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
       Associated with this extension, the <STRONG>init_pair</STRONG> function accepts negative
       arguments to specify default foreground or background colors.

       The  <STRONG>use_default_colors</STRONG>  function  was added to support <EM>ded</EM>.  This is a
       full-screen application which uses curses to manage only  part  of  the
       screen.  The bottom portion of the screen, which is of adjustable size,
       is left uncolored to display the results from shell commands.  The  top
       portion  of  the screen colors filenames using a scheme like the "color
       ls" programs.  Attempting to manage the background color of the  screen
       for this application would give unsatisfactory results for a variety of
       reasons.  This extension was devised after noting that color xterm (and
       similar  programs) provides a background color which does not necessar-
       ily correspond to any of the ANSI colors.   While  a  special  terminfo
       entry  could  be  constructed using nine colors, there was no mechanism
       provided within  curses  to  account  for  the  related  <STRONG>orig_pair</STRONG>  and
       <STRONG>back_color_erase</STRONG> capabilities.

       The <STRONG>assume_default_colors</STRONG> function was added to solve a different prob-
       lem: support for applications which would use environment variables and
       other  configuration to bypass curses' notion of the terminal's default
       colors, setting specific values.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       These routines are specific to ncurses.  They  were  not  supported  on
       Version 7, BSD or System V implementations.  It is recommended that any
       code depending on them be conditioned using NCURSES_VERSION.


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>, <STRONG>ded(1)</STRONG>.


</PRE><H2><a name="h2-AUTHOR">AUTHOR</a></H2><PRE>
       Thomas Dickey (from an analysis of the requirements for color xterm for
       XFree86 3.1.2C, February 1996).



                                                            <STRONG><A HREF="default_colors.3x.html">default_colors(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
<li><a href="#h2-AUTHOR">AUTHOR</a></li>
</ul>
</div>
</BODY>
</HTML>