diff options
Diffstat (limited to 'en_US.ISO8859-1/books/fdp-primer/sgml-markup/chapter.xml')
| -rw-r--r-- | en_US.ISO8859-1/books/fdp-primer/sgml-markup/chapter.xml | 2759 |
1 files changed, 2759 insertions, 0 deletions
diff --git a/en_US.ISO8859-1/books/fdp-primer/sgml-markup/chapter.xml b/en_US.ISO8859-1/books/fdp-primer/sgml-markup/chapter.xml new file mode 100644 index 0000000000..5c77eea354 --- /dev/null +++ b/en_US.ISO8859-1/books/fdp-primer/sgml-markup/chapter.xml @@ -0,0 +1,2759 @@ +<?xml version="1.0" encoding="iso-8859-1" standalone="no"?> +<!-- Copyright (c) 1998, 1999 Nik Clayton, All rights reserved. + + Redistribution and use in source (SGML DocBook) and 'compiled' forms + (SGML HTML, PDF, PostScript, RTF and so forth) with or without + modification, are permitted provided that the following conditions + are met: + + 1. Redistributions of source code (SGML DocBook) must retain the above + copyright notice, this list of conditions and the following + disclaimer as the first lines of this file unmodified. + + 2. Redistributions in compiled form (transformed to other DTDs, + converted to PDF, PostScript, RTF and other formats) must reproduce + the above copyright notice, this list of conditions and the + following disclaimer in the documentation and/or other materials + provided with the distribution. + + THIS DOCUMENTATION IS PROVIDED BY NIK CLAYTON "AS IS" AND ANY EXPRESS OR + IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + DISCLAIMED. IN NO EVENT SHALL NIK CLAYTON BE LIABLE FOR ANY DIRECT, + INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, EVEN IF ADVISED OF THE + POSSIBILITY OF SUCH DAMAGE. + + $FreeBSD$ +--> + +<chapter id="xml-markup"> + <title>XML Markup</title> + + <para>This chapter describes the two markup languages you will + encounter when you contribute to the FreeBSD documentation + project. Each section describes the markup language, and details + the markup that you are likely to want to use, or that is already + in use.</para> + + <para>These markup languages contain a large number of elements, and + it can be confusing sometimes to know which element to use for a + particular situation. This section goes through the elements you + are most likely to need, and gives examples of how you would use + them.</para> + + <para>This is <emphasis>not</emphasis> an exhaustive list of + elements, since that would just reiterate the documentation for + each language. The aim of this section is to list those elements + more likely to be useful to you. If you have a question about how + best to markup a particular piece of content, please post it to + the &a.doc;.</para> + + <note> + <title>Inline Versus Block</title> + + <para>In the remainder of this document, when describing elements, + <emphasis>inline</emphasis> means that the element can occur + within a block element, and does not cause a line break. A + <emphasis>block</emphasis> element, by comparison, will cause a + line break (and other processing) when it is encountered.</para> + </note> + + <sect1 id="xml-markup-xhtml"> + <title>XHTML</title> + + <para>XHTML is the XML version of the HyperText Markup Language, + which is the markup language + of choice on the World Wide Web. More information can be found + at <ulink url="http://www.w3.org/"></ulink>.</para> + + <para>XHTML is used to markup pages on the FreeBSD web site. It + should not (generally) be used to mark up other documentation, + since DocBook offers a far richer set of elements to choose + from. Consequently, you will normally only encounter XHTML pages + if you are writing for the web site.</para> + + <para>HTML has gone through a number of versions, 1, 2, 3.0, 3.2, + 4.0 and then an XML-compliant version has also been created, which + is called XHTML and the latest widespread version of it is + XHTML 1.0(available in both + <emphasis>strict</emphasis> and <emphasis>transitional</emphasis> + variants).</para> + + <para>The XHTML DTDs are available from the Ports Collection + in the <filename role="package">textproc/xhtml</filename> port. + They are automatically installed as part of the <filename + role="package">textproc/docproj</filename> port.</para> + + <sect2> + <title>Formal Public Identifier (FPI)</title> + + <para>There are a number of XHTML FPIs, depending upon the + version (also known as the level) of XHTML that you want to + declare your document to be compliant with.</para> + + <para>The majority of XHTML documents on the FreeBSD web site + comply with the transitional version of XHTML 1.0.</para> + + <programlisting>PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"</programlisting> + </sect2> + + <sect2> + <title>Sectional Elements</title> + + <para>An XHTML document is normally split into two sections. The + first section, called the <emphasis>head</emphasis>, contains + meta-information about the document, such as its title, the + name of the author, the parent document, and so on. The + second section, the <emphasis>body</emphasis>, contains the + content that will be displayed to the user.</para> + + <para>These sections are indicated with <sgmltag>head</sgmltag> + and <sgmltag>body</sgmltag> elements respectively. These + elements are contained within the top-level + <sgmltag>html</sgmltag> element.</para> + + <example> + <title>Normal XHTML Document Structure</title> + + <programlisting><html xmlns="http://www.w3.org/1999/xhtml"> + <head> + <title><replaceable>The Document's Title</replaceable></title> + </head> + + <body> + + … + + </body> +</html></programlisting> + </example> + </sect2> + + <sect2> + <title>Block Elements</title> + + <sect3> + <title>Headings</title> + + <para>XHTML allows you to denote headings in your document, at + up to six different levels.</para> + + <para>The largest and most prominent heading is + <sgmltag>h1</sgmltag>, then <sgmltag>h2</sgmltag>, + continuing down to <sgmltag>h6</sgmltag>.</para> + + <para>The element's content is the text of the heading.</para> + + <example> + <title><sgmltag>h1</sgmltag>, <sgmltag>h2</sgmltag>, + and Other Header Tags</title> + + <para>Use:</para> + + <programlisting><![CDATA[<h1>First section</h1> + +<!-- Document introduction goes here --> + +<h2>This is the heading for the first section</h2> + +<!-- Content for the first section goes here --> + +<h3>This is the heading for the first sub-section</h3> + +<!-- Content for the first sub-section goes here --> + +<h2>This is the heading for the second section</h2> + +<!-- Content for the second section goes here -->]]></programlisting> + </example> + + <para>Generally, an XHTML page should have one first level + heading (<sgmltag>h1</sgmltag>). This can contain many + second level headings (<sgmltag>h2</sgmltag>), which can in + turn contain many third level headings. Each + <sgmltag>h<replaceable>n</replaceable></sgmltag> element + should have the same element, but one further up the + hierarchy, preceding it. Leaving gaps in the numbering is + to be avoided.</para> + + <example> + <title>Bad Ordering of + <sgmltag>h<replaceable>n</replaceable></sgmltag> + Elements</title> + + <para>Use:</para> + + <programlisting><![CDATA[<h1>First section</h1> + +<!-- Document introduction --> + +<h3>Sub-section</h3> + +<!-- This is bad, <h2> has been left out -->]]></programlisting> + </example> + </sect3> + + <sect3> + <title>Paragraphs</title> + + <para>XHTML supports a single paragraph element, + <sgmltag>p</sgmltag>.</para> + + <example> + <title><sgmltag>p</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>This is a paragraph. It can contain just about any + other element.</p>]]></programlisting> + </example> + </sect3> + + <sect3> + <title>Block Quotations</title> + + <para>A block quotation is an extended quotation from another + document that should not appear within the current + paragraph.</para> + + <example> + <title><sgmltag>blockquote</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>A small excerpt from the US Constitution:</p> + +<blockquote>We the People of the United States, in Order to form + a more perfect Union, establish Justice, insure domestic + Tranquility, provide for the common defence, promote the general + Welfare, and secure the Blessings of Liberty to ourselves and our + Posterity, do ordain and establish this Constitution for the + United States of America.</blockquote>]]></programlisting> + </example> + </sect3> + + <sect3> + <title>Lists</title> + + <para>You can present the user with three types of lists, + ordered, unordered, and definition.</para> + + <para>Typically, each entry in an ordered list will be + numbered, while each entry in an unordered list will be + preceded by a bullet point. Definition lists are composed + of two sections for each entry. The first section is the + term being defined, and the second section is the definition + of the term.</para> + + <para>Ordered lists are indicated by the <sgmltag>ol</sgmltag> + element, unordered lists by the <sgmltag>ul</sgmltag> + element, and definition lists by the <sgmltag>dl</sgmltag> + element.</para> + + <para>Ordered and unordered lists contain listitems, indicated + by the <sgmltag>li</sgmltag> element. A listitem can + contain textual content, or it may be further wrapped in one + or more <sgmltag>p</sgmltag> elements.</para> + + <para>Definition lists contain definition terms + (<sgmltag>dt</sgmltag>) and definition descriptions + (<sgmltag>dd</sgmltag>). A definition term can only contain + inline elements. A definition description can contain other + block elements.</para> + + <example> + <title><sgmltag>ul</sgmltag> and + <sgmltag>ol</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>An unordered list. Listitems will probably be + preceded by bullets.</p> + +<ul> + <li>First item</li> + + <li>Second item</li> + + <li>Third item</li> +</ul> + +<p>An ordered list, with list items consisting of multiple + paragraphs. Each item (note: not each paragraph) will be + numbered.</p> + +<ol> + <li><p>This is the first item. It only has one paragraph.</p></li> + + <li><p>This is the first paragraph of the second item.</p> + + <p>This is the second paragraph of the second item.</p></li> + + <li><p>This is the first and only paragraph of the third + item.</p></li> +</ol>]]></programlisting> + </example> + + <example> + <title>Definition Lists with <sgmltag>dl</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<dl> + <dt>Term 1</dt> + + <dd><p>Paragraph 1 of definition 1.</p> + + <p>Paragraph 2 of definition 1.</p></dd> + + <dt>Term 2</dt> + + <dd><p>Paragraph 1 of definition 2.</p></dd> + + <dt>Term 3</dt> + + <dd><p>Paragraph 1 of definition 3.</p></dd> +</dl>]]></programlisting> + </example> + </sect3> + + <sect3> + <title>Pre-formatted Text</title> + + <para>You can indicate that text should be shown to the user + exactly as it is in the file. Typically, this means that + the text is shown in a fixed font, multiple spaces are not + merged into one, and line breaks in the text are + significant.</para> + + <para>In order to do this, wrap the content in the + <sgmltag>pre</sgmltag> element.</para> + + <example> + <title><sgmltag>pre</sgmltag></title> + + <para>You could use <sgmltag>pre</sgmltag> to mark up an + email message:</para> + + <programlisting><![CDATA[<pre> From: nik@FreeBSD.org + To: freebsd-doc@FreeBSD.org + Subject: New documentation available + + There is a new copy of my primer for contributors to the FreeBSD + Documentation Project available at + + <URL:http://people.FreeBSD.org/~nik/primer/index.html> + + Comments appreciated. + + N</pre>]]></programlisting> + + <para>Keep in mind that <literal><</literal> and + <literal>&</literal> still are recognized as special + characters in pre-formatted text. This is why the example + shown had to use <literal>&lt;</literal> instead of + <literal><</literal>. For consistency, + <literal>&gt;</literal> was used in place of + <literal>></literal>, too. Watch out for the special + characters that may appear in text copied from a + plain-text source, e.g., an email message or program + code.</para> + </example> + </sect3> + + <sect3> + <title>Tables</title> + + <note> + <para>Most text-mode browsers (such as Lynx) do not render + tables particularly effectively. If you are relying on + the tabular display of your content, you should consider + using alternative markup to prevent confusion.</para> + </note> + + <para>Mark up tabular information using the + <sgmltag>table</sgmltag> element. A table consists of one + or more table rows (<sgmltag>tr</sgmltag>), each containing + one or more cells of table data (<sgmltag>td</sgmltag>). + Each cell can contain other block elements, such as + paragraphs or lists. It can also contain another table + (this nesting can repeat indefinitely). If the cell only + contains one paragraph then you do not need to include the + <sgmltag>p</sgmltag> element.</para> + + <example> + <title>Simple Use of <sgmltag>table</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>This is a simple 2x2 table.</p> + +<table> + <tr> + <td>Top left cell</td> + + <td>Top right cell</td> + </tr> + + <tr> + <td>Bottom left cell</td> + + <td>Bottom right cell</td> + </tr> +</table>]]></programlisting></example> + + <para>A cell can span multiple rows and columns. To indicate + this, add the <literal>rowspan</literal> and/or + <literal>colspan</literal> attributes, with values + indicating the number of rows or columns that should be + spanned.</para> + + <example> + <title>Using <literal>rowspan</literal></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>One tall thin cell on the left, two short cells next to + it on the right.</p> + +<table> + <tr> + <td rowspan="2">Long and thin</td> + </tr> + + <tr> + <td>Top cell</td> + + <td>Bottom cell</td> + </tr> +</table>]]></programlisting> + </example> + + <example> + <title>Using <literal>colspan</literal></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>One long cell on top, two short cells below it.</p> + +<table> + <tr> + <td colspan="2">Top cell</td> + </tr> + + <tr> + <td>Bottom left cell</td> + + <td>Bottom right cell</td> + </tr> +</table>]]></programlisting> + </example> + + <example> + <title>Using <literal>rowspan</literal> and + <literal>colspan</literal> Together</title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>On a 3x3 grid, the top left block is a 2x2 set of + cells merged into one. The other cells are normal.</p> + +<table> + <tr> + <td colspan="2" rowspan="2">Top left large cell</td> + + <td>Top right cell</td> + </tr> + + <tr> + <!-- Because the large cell on the left merges into + this row, the first <td> will occur on its + right --> + + <td>Middle right cell</td> + </tr> + + <tr> + <td>Bottom left cell</td> + + <td>Bottom middle cell</td> + + <td>Bottom right cell</td> + </tr> +</table>]]></programlisting> + </example> + </sect3> + </sect2> + + <sect2> + <title>In-line Elements</title> + + <sect3> + <title>Emphasizing Information</title> + + <para>You have two levels of emphasis available in XHTML, + <sgmltag>em</sgmltag> and <sgmltag>strong</sgmltag>. + <sgmltag>em</sgmltag> is for a normal level of emphasis and + <sgmltag>strong</sgmltag> indicates stronger + emphasis.</para> + + <para>Typically, <sgmltag>em</sgmltag> is rendered in italic + and <sgmltag>strong</sgmltag> is rendered in bold. This is + not always the case, however, and you should not rely on + it. According to best practices, webpages only hold + structural and semantical information and stylesheets are + later applied to use these two so you should think of + semantics not formatting when using these tags.</para> + + <example> + <title><sgmltag>em</sgmltag> and + <sgmltag>strong</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p><em>This</em> has been emphasized, while + <strong>this</strong> has been strongly emphasized.</p>]]></programlisting> + </example> + </sect3> + + <sect3> + <title>Indicating Fixed-Pitch Text</title> + + <para>If you have content that should be rendered in a fixed + pitch (typewriter) typeface, use <sgmltag>tt</sgmltag> (for + <quote>teletype</quote>).</para> + + <example> + <title><sgmltag>tt</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>This document was originally written by + Nik Clayton, who can be reached by email as + <tt>nik@FreeBSD.org</tt>.</p>]]></programlisting> + </example> + </sect3> + </sect2> + + <sect2> + <title>Links</title> + + <note> + <para>Links are also inline elements.</para> + </note> + + <sect3> + <title>Linking to Other Documents on the WWW</title> + + <para>In order to include a link to another document on the + WWW you must know the URL of the document you want to link + to.</para> + + <para>The link is indicated with <sgmltag>a</sgmltag>, and the + <literal>href</literal> attribute contains the URL of the + target document. The content of the element becomes the + link, and is normally indicated to the user in some way + (underlining, change of color, different mouse cursor when + over the link, and so on).</para> + + <example> + <title>Using <literal><a href="..."></literal></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p>More information is available at the + <a href="http://www.FreeBSD.org/">FreeBSD web site</a>.</p>]]></programlisting> + </example> + + <para>These links will take the user to the top of the chosen + document.</para> + </sect3> + + <sect3> + <title>Linking to Other Parts of Documents</title> + + <para>Linking to a point within another document (or within + the same document) requires that the document author include + anchors that you can link to.</para> + + <para>Anchors are indicated with <sgmltag>a</sgmltag> and the + <literal>id</literal> attribute instead of + <literal>href</literal>.</para> + + <example> + <title>Using <literal><a id="..."></literal></title> + + <para>Use:</para> + + <programlisting><![CDATA[<p><a id="para1">This</a> paragraph can be referenced + in other links with the name <tt>para1</tt>.</p>]]></programlisting> + </example> + + <para>To link to a named part of a document, write a normal + link to that document, but include the id of the anchor + after a <literal>#</literal> symbol.</para> + + <example> + <title>Linking to a Named Part of Another Document</title> + + <para>Assume that the <literal>para1</literal> example + resides in a document called + <filename>foo.html</filename>.</para> + + <programlisting><![CDATA[<p>More information can be found in the + <a href="foo.html#para1">first paragraph</a> of + <tt>foo.html</tt>.</p>]]></programlisting> + </example> + + <para>If you are linking to a named anchor within the same + document then you can omit the document's URL, and just + include the name of the anchor (with the preceding + <literal>#</literal>).</para> + + <example> + <title>Linking to a Named Part of the Same Document</title> + + <para>Assume that the <literal>para1</literal> example + resides in this document:</para> + + <programlisting><![CDATA[<p>More information can be found in the + <a href="#para1">first paragraph</a> of this + document.</p>]]></programlisting> + </example> + </sect3> + </sect2> + </sect1> + + <sect1 id="xml-markup-docbook"> + <title>DocBook</title> + + <para>DocBook was originally developed by HaL Computer Systems and + O'Reilly & Associates to be a DTD for writing technical + documentation <footnote><para>A short history can be found under + <ulink + url="http://www.oasis-open.org/docbook/intro.shtml#d0e41"> + http://www.oasis-open.org/docbook/intro.shtml#d0e41</ulink>.</para></footnote>. + Since 1998 it is maintained by the <ulink + url="http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=docbook"> + DocBook Technical Committee</ulink>. As such, and unlike + LinuxDoc and XHTML, DocBook is very heavily oriented towards + markup that describes <emphasis>what</emphasis> something is, + rather than describing <emphasis>how</emphasis> it should be + presented.</para> + + <note> + <title>Formal Versus Informal</title> + + <para>Some elements may exist in two forms, + <emphasis>formal</emphasis> and <emphasis>informal</emphasis>. + Typically, the formal version of the element will consist of a + title followed by the informal version of the element. The + informal version will not have a title.</para> + </note> + + <para>The DocBook DTD is available from the Ports Collection + in the <filename role="package">textproc/docbook</filename> + port. It is automatically installed as part of the <filename + role="package">textproc/docproj</filename> port.</para> + + <sect2> + <title>&os; Extensions</title> + + <para>The FreeBSD Documentation Project has extended the DocBook + DTD by adding some new elements. These elements serve to make + some of the markup more precise.</para> + + <para>Where a FreeBSD specific element is listed below it is + clearly marked.</para> + + <para>Throughout the rest of this document, the term + <quote>DocBook</quote> is used to mean the FreeBSD extended + DocBook DTD.</para> + + <note> + <para>There is nothing about these extensions that is FreeBSD + specific, it was just felt that they were useful + enhancements for this particular project. Should anyone + from any of the other *nix camps (NetBSD, OpenBSD, Linux, + …) be interested in collaborating on a standard + DocBook extension set, please get in touch with + &a.doceng;.</para> + </note> + + <para>The &os; extensions are not (currently) in the + Ports Collection. They are stored in the &os; Subversion + tree, as <ulink + url="http://svnweb.FreeBSD.org/doc/head/share/sgml/freebsd.dtd">head/share/sgml/freebsd.dtd</ulink>.</para> + </sect2> + + <sect2> + <title>Formal Public Identifier (FPI)</title> + + <para>In compliance with the DocBook guidelines for writing FPIs + for DocBook customizations, the FPI for the FreeBSD extended + DocBook DTD is:</para> + + <programlisting>PUBLIC "-//FreeBSD//DTD DocBook V4.2-Based Extension//EN"</programlisting> + </sect2> + + <sect2> + <title>Document Structure</title> + + <para>DocBook allows you to structure your documentation in + several ways. In the FreeBSD Documentation Project we are + using two primary types of DocBook document: the book and the + article.</para> + + <para>A book is organized into <sgmltag>chapter</sgmltag>s. + This is a mandatory requirement. There may be + <sgmltag>part</sgmltag>s between the book and the chapter to + provide another layer of organization. For example, the + Handbook is arranged in this way.</para> + + <para>A chapter may (or may not) contain one or more sections. + These are indicated with the <sgmltag>sect1</sgmltag> element. + If a section contains another section then use the + <sgmltag>sect2</sgmltag> element, and so on, up to + <sgmltag>sect5</sgmltag>.</para> + + <para>Chapters and sections contain the remainder of the + content.</para> + + <para>An article is simpler than a book, and does not use + chapters. Instead, the content of an article is organized + into one or more sections, using the same + <sgmltag>sect1</sgmltag> (and <sgmltag>sect2</sgmltag> and so + on) elements that are used in books.</para> + + <para>Obviously, you should consider the nature of the + documentation you are writing in order to decide whether it is + best marked up as a book or an article. Articles are well + suited to information that does not need to be broken down + into several chapters, and that is, relatively speaking, quite + short, at up to 20-25 pages of content. Books are best suited + to information that can be broken up into several chapters, + possibly with appendices and similar content as well.</para> + + <para>The <ulink url="&url.base;/docs.html">FreeBSD + tutorials</ulink> are all marked up as articles, while this + document, the + <ulink url="&url.books.faq;/index.html">FreeBSD FAQ</ulink>, + and the <ulink url="&url.books.handbook;/index.html">FreeBSD + Handbook</ulink> are all marked up as books, for + example.</para> + + <sect3> + <title>Starting a Book</title> + + <para>The content of the book is contained within the + <sgmltag>book</sgmltag> element. As well as containing + structural markup, this element can contain elements that + include additional information about the book. This is + either meta-information, used for reference purposes, or + additional content used to produce a title page.</para> + + <para>This additional information should be contained within + <sgmltag>bookinfo</sgmltag>.</para> + + <example> + <title>Boilerplate <sgmltag>book</sgmltag> with + <sgmltag>bookinfo</sgmltag></title> + + <!-- Can't put this in a marked section because of the + replaceable elements --> + + <programlisting><book> + <bookinfo> + <title><replaceable>Your Title Here</replaceable></title> + + <author> + <firstname><replaceable>Your first name</replaceable></firstname> + <surname><replaceable>Your surname</replaceable></surname> + <affiliation> + <address><email><replaceable>Your email address</replaceable></email></address> + </affiliation> + </author> + + <copyright> + <year><replaceable>1998</replaceable></year> + <holder role="mailto:<replaceable>your email address</replaceable>"><replaceable>Your name</replaceable></holder> + </copyright> + + <releaseinfo>$FreeBSD$</releaseinfo> + + <abstract> + <para><replaceable>Include an abstract of the book's contents here.</replaceable></para> + </abstract> + </bookinfo> + + … + +</book></programlisting> + </example> + </sect3> + + <sect3> + <title>Starting an Article</title> + + <para>The content of the article is contained within the + <sgmltag>article</sgmltag> element. As well as containing + structural markup, this element can contain elements that + include additional information about the article. This is + either meta-information, used for reference purposes, or + additional content used to produce a title page.</para> + + <para>This additional information should be contained within + <sgmltag>articleinfo</sgmltag>.</para> + + <example> + <title>Boilerplate <sgmltag>article</sgmltag> with + <sgmltag>articleinfo</sgmltag></title> + + <!-- Can't put this in a marked section because of the + replaceable elements --> + + <programlisting><article> + <articleinfo> + <title><replaceable>Your title here</replaceable></title> + + <author> + <firstname><replaceable>Your first name</replaceable></firstname> + <surname><replaceable>Your surname</replaceable></surname> + <affiliation> + <address><email><replaceable>Your email address</replaceable></email></address> + </affiliation> + </author> + + <copyright> + <year><replaceable>1998</replaceable></year> + <holder role="mailto:<replaceable>your email address</replaceable>"><replaceable>Your name</replaceable></holder> + </copyright> + + <releaseinfo>$FreeBSD$</releaseinfo> + + <abstract> + <para><replaceable>Include an abstract of the article's contents here.</replaceable></para> + </abstract> + </articleinfo> + + … + +</article></programlisting> + </example> + </sect3> + + <sect3> + <title>Indicating Chapters</title> + + <para>Use <sgmltag>chapter</sgmltag> to mark up your chapters. + Each chapter has a mandatory <sgmltag>title</sgmltag>. + Articles do not contain chapters, they are reserved for + books.</para> + + <example> + <title>A Simple Chapter</title> + + <programlisting><![CDATA[<chapter> + <title>The Chapter's Title</title> + + ... +</chapter>]]></programlisting> + </example> + + <para>A chapter cannot be empty; it must contain elements in + addition to <sgmltag>title</sgmltag>. If you need to + include an empty chapter then just use an empty + paragraph.</para> + + <example> + <title>Empty Chapters</title> + + <programlisting><![CDATA[<chapter> + <title>This is An Empty Chapter</title> + + <para></para> +</chapter>]]></programlisting> + </example> + </sect3> + + <sect3> + <title>Sections Below Chapters</title> + + <para>In books, chapters may (but do not need to) be broken up + into sections, subsections, and so on. In articles, + sections are the main structural element, and each article + must contain at least one section. Use the + <sgmltag>sect<replaceable>n</replaceable></sgmltag> element. + The <replaceable>n</replaceable> indicates the section + number, which identifies the section level.</para> + + <para>The first + <sgmltag>sect<replaceable>n</replaceable></sgmltag> is + <sgmltag>sect1</sgmltag>. You can have one or more of these + in a chapter. They can contain one or more + <sgmltag>sect2</sgmltag> elements, and so on, down to + <sgmltag>sect5</sgmltag>.</para> + + <example> + <title>Sections in Chapters</title> + + <programlisting><![CDATA[<chapter> + <title>A Sample Chapter</title> + + <para>Some text in the chapter.</para> + + <sect1> + <title>First Section (1.1)</title> + + … + </sect1> + + <sect1> + <title>Second Section (1.2)</title> + + <sect2> + <title>First Sub-Section (1.2.1)</title> + + <sect3> + <title>First Sub-Sub-Section (1.2.1.1)</title> + + … + </sect3> + </sect2> + + <sect2> + <title>Second Sub-Section (1.2.2)</title> + + … + </sect2> + </sect1> +</chapter>]]></programlisting> + </example> + + <note> + <para>This example includes section numbers in the section + titles. You should not do this in your documents. Adding + the section numbers is carried out by the stylesheets (of + which more later), and you do not need to manage them + yourself.</para> + </note> + </sect3> + + <sect3> + <title>Subdividing Using <sgmltag>part</sgmltag> + Elements</title> + + <para>You can introduce another layer of organization between + <sgmltag>book</sgmltag> and <sgmltag>chapter</sgmltag> with + one or more <sgmltag>part</sgmltag>s. This cannot be done + in an <sgmltag>article</sgmltag>.</para> + + <programlisting><![CDATA[<part> + <title>Introduction</title> + + <chapter> + <title>Overview</title> + + ... + </chapter> + + <chapter> + <title>What is FreeBSD?</title> + + ... + </chapter> + + <chapter> + <title>History</title> + + ... + </chapter> +</part>]]></programlisting> + </sect3> + </sect2> + + <sect2> + <title>Block Elements</title> + + <sect3> + <title>Paragraphs</title> + + <para>DocBook supports three types of paragraphs: + <sgmltag>formalpara</sgmltag>, <sgmltag>para</sgmltag>, and + <sgmltag>simpara</sgmltag>.</para> + + <para>Most of the time you will only need to use + <sgmltag>para</sgmltag>. <sgmltag>formalpara</sgmltag> + includes a <sgmltag>title</sgmltag> element, and + <sgmltag>simpara</sgmltag> disallows some elements from + within <sgmltag>para</sgmltag>. Stick with + <sgmltag>para</sgmltag>.</para> + + <example> + <title><sgmltag>para</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>This is a paragraph. It can contain just about any + other element.</para> ]]></programlisting> + + <para>Appearance:</para> + + <para>This is a paragraph. It can contain just about any + other element.</para> + </example> + </sect3> + + <sect3> + <title>Block Quotations</title> + + <para>A block quotation is an extended quotation from another + document that should not appear within the current + paragraph. You will probably only need it + infrequently.</para> + + <para>Blockquotes can optionally contain a title and an + attribution (or they can be left untitled and + unattributed).</para> + + <example> + <title><sgmltag>blockquote</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>A small excerpt from the US Constitution:</para> + +<blockquote> + <title>Preamble to the Constitution of the United States</title> + + <attribution>Copied from a web site somewhere</attribution> + + <para>We the People of the United States, in Order to form a more perfect + Union, establish Justice, insure domestic Tranquility, provide for the + common defence, promote the general Welfare, and secure the Blessings + of Liberty to ourselves and our Posterity, do ordain and establish this + Constitution for the United States of America.</para> +</blockquote>]]></programlisting> + + <para>Appearance:</para> + + <para>A small excerpt from the US Constitution:</para> + + <blockquote> + <title>Preamble to the Constitution of the United + States</title> + + <attribution>Copied from a web site + somewhere</attribution> + + <para>We the People of the United States, in Order to form + a more perfect Union, establish Justice, insure domestic + Tranquility, provide for the common defence, promote the + general Welfare, and secure the Blessings of Liberty to + ourselves and our Posterity, do ordain and establish + this Constitution for the United States of + America.</para> + </blockquote> + </example> + </sect3> + + <sect3> + <title>Tips, Notes, Warnings, Cautions, Important Information + and Sidebars</title> + + <para>You may need to include extra information separate from + the main body of the text. Typically this is + <quote>meta</quote> information that the user should be + aware of.</para> + + <para>Depending on the nature of the information, one of + <sgmltag>tip</sgmltag>, <sgmltag>note</sgmltag>, + <sgmltag>warning</sgmltag>, <sgmltag>caution</sgmltag>, and + <sgmltag>important</sgmltag> should be used. Alternatively, + if the information is related to the main text but is not + one of the above, use <sgmltag>sidebar</sgmltag>.</para> + + <para>The circumstances in which to choose one of these + elements over another is unclear. The DocBook documentation + suggests:</para> + + <itemizedlist> + <listitem> + <para>A Note is for information that should be heeded by + all readers.</para> + </listitem> + + <listitem> + <para>An Important element is a variation on Note.</para> + </listitem> + + <listitem> + <para>A Caution is for information regarding possible data + loss or software damage.</para> + </listitem> + + <listitem> + <para>A Warning is for information regarding possible + hardware damage or injury to life or limb.</para> + </listitem> + </itemizedlist> + + <example> + <title><sgmltag>warning</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<warning> + <para>Installing FreeBSD may make you want to delete Windows from your + hard disk.</para> +</warning>]]></programlisting> + </example> + + <para>Appearance:</para> + <!-- Need to do this outside of the example --> + <warning> + <para>Installing FreeBSD may make you want to delete Windows + from your hard disk.</para> + </warning> + </sect3> + + <sect3> + <title>Lists and Procedures</title> + + <para>You will often need to list pieces of information to the + user, or present them with a number of steps that must be + carried out in order to accomplish a particular goal.</para> + + <para>In order to do this, use + <sgmltag>itemizedlist</sgmltag>, + <sgmltag>orderedlist</sgmltag>, or + <sgmltag>procedure</sgmltag><footnote><para>There are other + types of list element in DocBook, but we are not + concerned with those at the + moment.</para></footnote></para> + + <para><sgmltag>itemizedlist</sgmltag> and + <sgmltag>orderedlist</sgmltag> are similar to their + counterparts in HTML, <sgmltag>ul</sgmltag> and + <sgmltag>ol</sgmltag>. Each one consists of one or more + <sgmltag>listitem</sgmltag> elements, and each + <sgmltag>listitem</sgmltag> contains one or more block + elements. The <sgmltag>listitem</sgmltag> elements are + analogous to HTML's <sgmltag>li</sgmltag> tags. However, + unlike HTML, they are required.</para> + + <para><sgmltag>procedure</sgmltag> is slightly different. It + consists of <sgmltag>step</sgmltag>s, which may in turn + consists of more <sgmltag>step</sgmltag>s or + <sgmltag>substep</sgmltag>s. Each <sgmltag>step</sgmltag> + contains block elements.</para> + + <example> + <title><sgmltag>itemizedlist</sgmltag>, + <sgmltag>orderedlist</sgmltag>, and + <sgmltag>procedure</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<itemizedlist> + <listitem> + <para>This is the first itemized item.</para> + </listitem> + + <listitem> + <para>This is the second itemized item.</para> + </listitem> +</itemizedlist> + +<orderedlist> + <listitem> + <para>This is the first ordered item.</para> + </listitem> + + <listitem> + <para>This is the second ordered item.</para> + </listitem> +</orderedlist> + +<procedure> + <step> + <para>Do this.</para> + </step> + + <step> + <para>Then do this.</para> + </step> + + <step> + <para>And now do this.</para> + </step> +</procedure>]]></programlisting> + + <para>Appearance:</para> + + <itemizedlist> + <listitem> + <para>This is the first itemized item.</para> + </listitem> + + <listitem> + <para>This is the second itemized item.</para> + </listitem> + </itemizedlist> + + <orderedlist> + <listitem> + <para>This is the first ordered item.</para> + </listitem> + + <listitem> + <para>This is the second ordered item.</para> + </listitem> + </orderedlist> + </example> + + <!-- Can't have <procedure> inside <example>, so this is a cheat --> + + <procedure> + <step> + <para>Do this.</para> + </step> + + <step> + <para>Then do this.</para> + </step> + + <step> + <para>And now do this.</para> + </step> + </procedure> + </sect3> + + <sect3> + <title>Showing File Samples</title> + + <para>If you want to show a fragment of a file (or perhaps a + complete file) to the user, wrap it in the + <sgmltag>programlisting</sgmltag> element.</para> + + <para>White space and line breaks within + <sgmltag>programlisting</sgmltag> <emphasis>are</emphasis> + significant. In particular, this means that the opening tag + should appear on the same line as the first line of the + output, and the closing tag should appear on the same line + as the last line of the output, otherwise spurious blank + lines may be included.</para> + + <example> + <title><sgmltag>programlisting</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>When you have finished, your program should look like + this:</para> + +<programlisting>#include <stdio.h> + +int +main(void) +{ + printf("hello, world\n"); +}</programlisting>]]></programlisting> + + <para>Notice how the angle brackets in the + <literal>#include</literal> line need to be referenced by + their entities instead of being included literally.</para> + + <para>Appearance:</para> + + <para>When you have finished, your program should look like + this:</para> + + <programlisting>#include <stdio.h> + +int +main(void) +{ + printf("hello, world\n"); +}</programlisting> + </example> + </sect3> + + <sect3> + <title>Callouts</title> + + <para>A callout is a mechanism for referring back to an + earlier piece of text or specific position within an earlier + example without linking to it within the text.</para> + + <para>To do this, mark areas of interest in your example + (<sgmltag>programlisting</sgmltag>, + <sgmltag>literallayout</sgmltag>, or whatever) with the + <sgmltag>co</sgmltag> element. Each element must have a + unique <literal>id</literal> assigned to it. After the + example include a <sgmltag>calloutlist</sgmltag> that refers + back to the example and provides additional + commentary.</para> + + <example> + <title><sgmltag>co</sgmltag> and + <sgmltag>calloutlist</sgmltag></title> + + <programlisting><![CDATA[<para>When you have finished, your program should look like + this:</para> + +<programlisting>#include <stdio.h> <co id="co-ex-include"/> + +int <co id="co-ex-return"/> +main(void) +{ + printf("hello, world\n"); <co id="co-ex-printf"/> +}</programlisting> + +<calloutlist> + <callout arearefs="co-ex-include"> + <para>Includes the standard IO header file.</para> + </callout> + + <callout arearefs="co-ex-return"> + <para>Specifies that <function>main()</function> returns an + int.</para> + </callout> + + <callout arearefs="co-ex-printf"> + <para>The <function>printf()</function> call that writes + <literal>hello, world</literal> to standard output.</para> + </callout> +</calloutlist>]]></programlisting> + + <para>Appearance:</para> + + <para>When you have finished, your program should look like + this:</para> + + <programlisting>#include <stdio.h> <co id="co-ex-include"/> + +int <co id="co-ex-return"/> +main(void) +{ + printf("hello, world\n"); <co id="co-ex-printf"/> +}</programlisting> + + <calloutlist> + <callout arearefs="co-ex-include"> + <para>Includes the standard IO header file.</para> + </callout> + + <callout arearefs="co-ex-return"> + <para>Specifies that <function>main()</function> returns + an int.</para> + </callout> + + <callout arearefs="co-ex-printf"> + <para>The <function>printf()</function> call that writes + <literal>hello, world</literal> to standard + output.</para> + </callout> + </calloutlist> + </example> + </sect3> + + <sect3> + <title>Tables</title> + + <para>Unlike HTML, you do not need to use tables for layout + purposes, as the stylesheet handles those issues for you. + Instead, just use tables for marking up tabular data.</para> + + <para>In general terms (and see the DocBook documentation for + more detail) a table (which can be either formal or + informal) consists of a <sgmltag>table</sgmltag> element. + This contains at least one <sgmltag>tgroup</sgmltag> + element, which specifies (as an attribute) the number of + columns in this table group. Within the tablegroup you can + then have one <sgmltag>thead</sgmltag> element, which + contains elements for the table headings (column headings), + and one <sgmltag>tbody</sgmltag> which contains the body of + the table.</para> + + <para>Both <sgmltag>tgroup</sgmltag> and + <sgmltag>thead</sgmltag> contain <sgmltag>row</sgmltag> + elements, which in turn contain <sgmltag>entry</sgmltag> + elements. Each <sgmltag>entry</sgmltag> element specifies + one cell in the table.</para> + + <example> + <title><sgmltag>informaltable</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<informaltable pgwide="1"> + <tgroup cols="2"> + <thead> + <row> + <entry>This is Column Head 1</entry> + <entry>This is Column Head 2</entry> + </row> + </thead> + + <tbody> + <row> + <entry>Row 1, column 1</entry> + <entry>Row 1, column 2</entry> + </row> + + <row> + <entry>Row 2, column 1</entry> + <entry>Row 2, column 2</entry> + </row> + </tbody> + </tgroup> +</informaltable>]]></programlisting> + + <para>Appearance:</para> + + <informaltable pgwide="1"> + <tgroup cols="2"> + <thead> + <row> + <entry>This is Column Head 1</entry> + <entry>This is Column Head 2</entry> + </row> + </thead> + + <tbody> + <row> + <entry>Row 1, column 1</entry> + <entry>Row 1, column 2</entry> + </row> + + <row> + <entry>Row 2, column 1</entry> + <entry>Row 2, column 2</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </example> + + <para>Always use the <literal>pgwide</literal> attribute with + a value of <literal>1</literal> with the + <sgmltag>informaltable</sgmltag> element. A bug in Internet + Explorer can cause the table to render incorrectly if this + is omitted.</para> + + <para>If you do not want a border around the table the + <literal>frame</literal> attribute can be added to the + <sgmltag>informaltable</sgmltag> element with a value of + <literal>none</literal> (i.e., <literal><informaltable + frame="none"></literal>).</para> + + <example> + <title>Tables Where <literal>frame="none"</literal></title> + + <para>Appearance:</para> + + <informaltable frame="none" pgwide="1"> + <tgroup cols="2"> + <thead> + <row> + <entry>This is Column Head 1</entry> + <entry>This is Column Head 2</entry> + </row> + </thead> + + <tbody> + <row> + <entry>Row 1, column 1</entry> + <entry>Row 1, column 2</entry> + </row> + + <row> + <entry>Row 2, column 1</entry> + <entry>Row 2, column 2</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </example> + </sect3> + + <sect3> + <title>Examples for the User to Follow</title> + + <para>A lot of the time you need to show examples for the user + to follow. Typically, these will consist of dialogs with + the computer; the user types in a command, the user gets a + response back, they type in another command, and so + on.</para> + + <para>A number of distinct elements and entities come into + play here.</para> + + <variablelist> + <varlistentry> + <term><sgmltag>screen</sgmltag></term> + + <listitem> + <para>Everything the user sees in this example will be + on the computer screen, so the next element is + <sgmltag>screen</sgmltag>.</para> + + <para>Within <sgmltag>screen</sgmltag>, white space is + significant.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><sgmltag>prompt</sgmltag>, + <literal>&prompt.root;</literal> and + <literal>&prompt.user;</literal></term> + + <listitem> + <para>Some of the things the user will be seeing on the + screen are prompts from the computer (either from the + operating system, command shell, or application). + These should be marked up using + <sgmltag>prompt</sgmltag>.</para> + + <para>As a special case, the two shell prompts for the + normal user and the root user have been provided as + entities. Every time you want to indicate the user is + at a shell prompt, use one of + <literal>&prompt.root;</literal> and + <literal>&prompt.user;</literal> as necessary. + They do not need to be inside + <sgmltag>prompt</sgmltag>.</para> + + <note> + <para><literal>&prompt.root;</literal> and + <literal>&prompt.user;</literal> are FreeBSD + extensions to DocBook, and are not part of the + original DTD.</para> + </note> + </listitem> + </varlistentry> + + <varlistentry> + <term><sgmltag>userinput</sgmltag></term> + + <listitem> + <para>When displaying text that the user should type in, + wrap it in <sgmltag>userinput</sgmltag> tags. It will + probably be displayed differently to the user.</para> + </listitem> + </varlistentry> + </variablelist> + + <example> + <title><sgmltag>screen</sgmltag>, <sgmltag>prompt</sgmltag>, + and <sgmltag>userinput</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<screen>&prompt.user; <userinput>ls -1</userinput> +foo1 +foo2 +foo3 +&prompt.user; <userinput>ls -1 | grep foo2</userinput> +foo2 +&prompt.user; <userinput>su</userinput> +<prompt>Password: </prompt> +&prompt.root; <userinput>cat foo2</userinput> +This is the file called 'foo2'</screen>]]></programlisting> + + <para>Appearance:</para> + + <screen>&prompt.user; <userinput>ls -1</userinput> +foo1 +foo2 +foo3 +&prompt.user; <userinput>ls -1 | grep foo2</userinput> +foo2 +&prompt.user; <userinput>su</userinput> +<prompt>Password: </prompt> +&prompt.root; <userinput>cat foo2</userinput> +This is the file called 'foo2'</screen> + </example> + + <note> + <para>Even though we are displaying the contents of the file + <filename>foo2</filename>, it is <emphasis>not</emphasis> + marked up as <sgmltag>programlisting</sgmltag>. Reserve + <sgmltag>programlisting</sgmltag> for showing fragments of + files outside the context of user actions.</para> + </note> + </sect3> + </sect2> + + <sect2> + <title>In-line Elements</title> + + <sect3> + <title>Emphasizing Information</title> + + <para>When you want to emphasize a particular word or phrase, + use <sgmltag>emphasis</sgmltag>. This may be presented as + italic, or bold, or might be spoken differently with a + text-to-speech system.</para> + + <para>There is no way to change the presentation of the + emphasis within your document, no equivalent of HTML's + <sgmltag>b</sgmltag> and <sgmltag>i</sgmltag>. If the + information you are presenting is important then consider + presenting it in <sgmltag>important</sgmltag> rather than + <sgmltag>emphasis</sgmltag>.</para> + + <example> + <title><sgmltag>emphasis</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>FreeBSD is without doubt <emphasis>the</emphasis> + premiere Unix like operating system for the Intel architecture.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>FreeBSD is without doubt <emphasis>the</emphasis> + premiere Unix like operating system for the Intel + architecture.</para> + </example> + </sect3> + + <sect3> + <title>Quotations</title> + + <para>To quote text from another document or source, or to + denote a phrase that is used figuratively, use + <sgmltag>quote</sgmltag>. Within a <sgmltag>quote</sgmltag> + tag, you may use most of the markup tags available for + normal text.</para> + + <example> + <title>Quotations</title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>However, make sure that the search does not go beyond the + <quote>boundary between local and public administration</quote>, + as RFC 1535 calls it.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>However, make sure that the search does not go beyond + the <quote>boundary between local and public + administration</quote>, as RFC 1535 calls it.</para> + </example> + </sect3> + + <sect3> + <title>Keys, Mouse Buttons, and Combinations</title> + + <para>To refer to a specific key on the keyboard, use + <sgmltag>keycap</sgmltag>. To refer to a mouse button, use + <sgmltag>mousebutton</sgmltag>. And to refer to + combinations of key presses or mouse clicks, wrap them all + in <sgmltag>keycombo</sgmltag>.</para> + + <para><sgmltag>keycombo</sgmltag> has an attribute called + <literal>action</literal>, which may be one of + <literal>click</literal>, <literal>double-click</literal>, + <literal>other</literal>, <literal>press</literal>, + <literal>seq</literal>, or <literal>simul</literal>. The + last two values denote whether the keys or buttons should be + pressed in sequence, or simultaneously.</para> + + <para>The stylesheets automatically add any connecting + symbols, such as <literal>+</literal>, between the key + names, when wrapped in <sgmltag>keycombo</sgmltag>.</para> + + <example> + <title>Keys, Mouse Buttons, and Combinations</title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>To switch to the second virtual terminal, press + <keycombo action="simul"><keycap>Alt</keycap> + <keycap>F1</keycap></keycombo>.</para> + +<para>To exit <command>vi</command> without saving your work, type + <keycombo action="seq"><keycap>Esc</keycap><keycap>:</keycap> + <keycap>q</keycap><keycap>!</keycap></keycombo>.</para> + +<para>My window manager is configured so that + <keycombo action="simul"><keycap>Alt</keycap> + <mousebutton>right</mousebutton> + </keycombo> mouse button is used to move windows.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>To switch to the second virtual terminal, press + <keycombo action="simul"><keycap>Alt</keycap> + <keycap>F1</keycap></keycombo>.</para> + + <para>To exit <command>vi</command> without saving your + work, type <keycombo action="seq"> + <keycap>Esc</keycap> + <keycap>:</keycap> + <keycap>q</keycap> + <keycap>!</keycap></keycombo>.</para> + + <para>My window manager is configured so that + <keycombo action="simul"> + <keycap>Alt</keycap> + <mousebutton>right</mousebutton></keycombo> mouse button + is used to move windows.</para> + </example> + </sect3> + + <sect3> + <title>Applications, Commands, Options, and Cites</title> + + <para>You will frequently want to refer to both applications + and commands when writing documentation. The distinction + between them is simple: an application is the name for a + suite (or possibly just 1) of programs that fulfill a + particular task. A command is the name of a program that + the user can run.</para> + + <para>In addition, you will occasionally need to list one or + more of the options that a command might take.</para> + + <para>Finally, you will often want to list a command with its + manual section number, in the <quote>command(number)</quote> + format so common in Unix manuals.</para> + + <para>Mark up application names with + <sgmltag>application</sgmltag>.</para> + + <para>When you want to list a command with its manual section + number (which should be most of the time) the DocBook + element is <sgmltag>citerefentry</sgmltag>. This will + contain a further two elements, + <sgmltag>refentrytitle</sgmltag> and + <sgmltag>manvolnum</sgmltag>. The content of + <sgmltag>refentrytitle</sgmltag> is the name of the command, + and the content of <sgmltag>manvolnum</sgmltag> is the + manual page section.</para> + + <para>This can be cumbersome to write, and so a series of + <link linkend="xml-primer-general-entities">general + entities</link> have been created to make this easier. + Each entity takes the form + <literal>&man.<replaceable>manual-page</replaceable>.<replaceable>manual-section</replaceable>;</literal>.</para> + + <para>The file that contains these entities is in + <filename>doc/share/sgml/man-refs.ent</filename>, and can be + referred to using this FPI:</para> + + <programlisting>PUBLIC "-//FreeBSD//ENTITIES DocBook Manual Page Entities//EN"</programlisting> + + <para>Therefore, the introduction to your documentation will + probably look like this:</para> + + <programlisting><!DOCTYPE book PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN" [ + +<!ENTITY % man PUBLIC "-//FreeBSD//ENTITIES DocBook Manual Page Entities//EN"> +%man; + +… + +]></programlisting> + + <para>Use <sgmltag>command</sgmltag> when you want to include + a command name <quote>in-line</quote> but present it as + something the user should type in.</para> + + <para>Use <sgmltag>option</sgmltag> to mark up the options + which will be passed to a command.</para> + + <para>When referring to the same command multiple times in + close proximity it is preferred to use the + <literal>&man.<replaceable>command</replaceable>.<replaceable>section</replaceable>;</literal> + notation to markup the first reference and use + <sgmltag>command</sgmltag> to markup subsequent references. + This makes the generated output, especially HTML, appear + visually better.</para> + + <para>This can be confusing, and sometimes the choice is not + always clear. Hopefully this example makes it + clearer.</para> + + <example> + <title>Applications, Commands, and Options</title> + + <para>Use:</para> + + <programlisting><![CDATA[<para><application>Sendmail</application> is the most + widely used Unix mail application.</para> + +<para><application>Sendmail</application> includes the + <citerefentry> + <refentrytitle>sendmail</refentrytitle> + <manvolnum>8</manvolnum> + </citerefentry>, &man.mailq.1;, and &man.newaliases.1; + programs.</para> + +<para>One of the command line parameters to <citerefentry> + <refentrytitle>sendmail</refentrytitle> + <manvolnum>8</manvolnum> + </citerefentry>, <option>-bp</option>, will display the current + status of messages in the mail queue. Check this on the command + line by running <command>sendmail -bp</command>.</para>]]></programlisting> + + <para>Appearance:</para> + + <para><application>Sendmail</application> is the most widely + used Unix mail application.</para> + + <para><application>Sendmail</application> includes the + <citerefentry> + <refentrytitle>sendmail</refentrytitle> + <manvolnum>8</manvolnum> + </citerefentry>, &man.mailq.1;, and &man.newaliases.1; + programs.</para> + + <para>One of the command line parameters to + <citerefentry> + <refentrytitle>sendmail</refentrytitle> + <manvolnum>8</manvolnum> + </citerefentry>, <option>-bp</option>, will display the + current status of messages in the mail queue. Check this + on the command line by running + <command>sendmail -bp</command>.</para> + </example> + + <note> + <para>Notice how the + <literal>&man.<replaceable>command</replaceable>.<replaceable>section</replaceable>;</literal> + notation is easier to follow.</para> + </note> + </sect3> + + <sect3> + <title>Files, Directories, Extensions</title> + + <para>Whenever you wish to refer to the name of a file, a + directory, or a file extension, use + <sgmltag>filename</sgmltag>.</para> + + <example> + <title><sgmltag>filename</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>The SGML source for the Handbook in English can be + found in <filename class="directory">/usr/doc/en_US.ISO8859-1/books/handbook/</filename>. The first + file is called <filename>book.xml</filename> in that + directory. You should also see a <filename>Makefile</filename> + and a number of files with a <filename>.ent</filename> + extension.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>The SGML source for the Handbook in English can be + found in <filename>/usr/doc/en/handbook/</filename>. The + first file is called <filename>handbook.xml</filename> in + that directory. You should also see a + <filename>Makefile</filename> and a number of files with a + <filename>.ent</filename> extension.</para> + </example> + </sect3> + + <sect3> + <title>The Name of Ports</title> + + <note> + <title>&os; Extension</title> + + <para>These elements are part of the FreeBSD extension to + DocBook, and do not exist in the original DocBook + DTD.</para> + </note> + + <para>You might need to include the name of a program from the + FreeBSD Ports Collection in the documentation. Use the + <sgmltag>filename</sgmltag> tag with the + <literal>role</literal> attribute set to + <literal>package</literal> to identify these. Since ports + can be installed in any number of locations, only include + the category and the port name; do not include + <filename>/usr/ports</filename>.</para> + + <example> + <title><sgmltag>filename</sgmltag> Tag with + <literal>package</literal> Role</title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>Install the <filename role="package">net/ethereal</filename> port to view network traffic.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>Install the <filename + role="package">net/ethereal</filename> port to view + network traffic.</para> + </example> + </sect3> + + <sect3> + <title>Devices</title> + + <note> + <title>&os; Extension</title> + + <para>These elements are part of the FreeBSD extension to + DocBook, and do not exist in the original DocBook + DTD.</para> + </note> + + <para>When referring to devices you have two choices. You can + either refer to the device as it appears in + <filename>/dev</filename>, or you can use the name of the + device as it appears in the kernel. For this latter course, + use <sgmltag>devicename</sgmltag>.</para> + + <para>Sometimes you will not have a choice. Some devices, + such as networking cards, do not have entries in + <filename>/dev</filename>, or the entries are markedly + different from those entries.</para> + + <example> + <title><sgmltag>devicename</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para><devicename>sio</devicename> is used for serial + communication in FreeBSD. <devicename>sio</devicename> manifests + through a number of entries in <filename>/dev</filename>, including + <filename>/dev/ttyd0</filename> and <filename>/dev/cuaa0</filename>.</para> + +<para>By contrast, the networking devices, such as + <devicename>ed0</devicename> do not appear in <filename>/dev</filename>.</para> + +<para>In MS-DOS, the first floppy drive is referred to as + <devicename>a:</devicename>. In FreeBSD it is + <filename>/dev/fd0</filename>.</para>]]></programlisting> + + <para>Appearance:</para> + + <para><devicename>sio</devicename> is used for serial + communication in FreeBSD. <devicename>sio</devicename> + manifests through a number of entries in + <filename>/dev</filename>, including + <filename>/dev/ttyd0</filename> and + <filename>/dev/cuaa0</filename>.</para> + + <para>By contrast, the networking devices, such as + <devicename>ed0</devicename> do not appear in + <filename>/dev</filename>.</para> + + <para>In MS-DOS, the first floppy drive is referred to as + <devicename>a:</devicename>. In FreeBSD it is + <filename>/dev/fd0</filename>.</para> + </example> + </sect3> + + <sect3> + <title>Hosts, Domains, IP Addresses, and So Forth</title> + + <note> + <title>&os; Extension</title> + + <para>These elements are part of the FreeBSD extension to + DocBook, and do not exist in the original DocBook + DTD.</para> + </note> + + <para>You can markup identification information for networked + computers (hosts) in several ways, depending on the nature + of the information. All of them use + <sgmltag>hostid</sgmltag> as the element, with the + <literal>role</literal> attribute selecting the type of the + marked up information.</para> + + <variablelist> + <varlistentry> + <term>No <literal>role</literal> attribute, or + <literal>role="hostname"</literal></term> + + <listitem> + <para>With no <literal>role</literal> attribute (i.e., + <sgmltag>hostid</sgmltag>...<sgmltag>/hostid</sgmltag>) + the marked up information is the simple hostname, such + as <literal>freefall</literal> or + <literal>wcarchive</literal>. You can explicitly + specify this with + <literal>role="hostname"</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>role="domainname"</literal></term> + + <listitem> + <para>The text is a domain name, such as + <literal>FreeBSD.org</literal> or + <literal>ngo.org.uk</literal>. There is no hostname + component.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>role="fqdn"</literal></term> + + <listitem> + <para>The text is a Fully Qualified Domain Name, with + both hostname and domain name parts.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>role="ipaddr"</literal></term> + + <listitem> + <para>The text is an IP address, probably expressed as a + dotted quad.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>role="ip6addr"</literal></term> + + <listitem> + <para>The text is an IPv6 address.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>role="netmask"</literal></term> + + <listitem> + <para>The text is a network mask, which might be + expressed as a dotted quad, a hexadecimal string, or + as a <literal>/</literal> followed by a number.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>role="mac"</literal></term> + + <listitem> + <para>The text is an Ethernet MAC address, expressed as + a series of 2 digit hexadecimal numbers separated by + colons.</para> + </listitem> + </varlistentry> + </variablelist> + + <example> + <title><sgmltag>hostid</sgmltag> and Roles</title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>The local machine can always be referred to by the + name <hostid>localhost</hostid>, which will have the IP address + <hostid role="ipaddr">127.0.0.1</hostid>.</para> + +<para>The <hostid role="domainname">FreeBSD.org</hostid> domain + contains a number of different hosts, including + <hostid role="fqdn">freefall.FreeBSD.org</hostid> and + <hostid role="fqdn">pointyhat.FreeBSD.org</hostid>.</para> + +<para>When adding an IP alias to an interface (using + <command>ifconfig</command>) <emphasis>always</emphasis> use a + netmask of <hostid role="netmask">255.255.255.255</hostid> + (which can also be expressed as <hostid + role="netmask">0xffffffff</hostid>).</para> + +<para>The MAC address uniquely identifies every network card + in existence. A typical MAC address looks like <hostid + role="mac">08:00:20:87:ef:d0</hostid>.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>The local machine can always be referred to by the + name <hostid>localhost</hostid>, which will have the IP + address <hostid role="ipaddr">127.0.0.1</hostid>.</para> + + <para>The <hostid role="domainname">FreeBSD.org</hostid> + domain contains a number of different hosts, including + <hostid role="fqdn">freefall.FreeBSD.org</hostid> and + <hostid role="fqdn">bento.FreeBSD.org</hostid>.</para> + + <para>When adding an IP alias to an interface (using + <command>ifconfig</command>) <emphasis>always</emphasis> + use a netmask of + <hostid role="netmask">255.255.255.255</hostid> + (which can also be expressed as <hostid + role="netmask">0xffffffff</hostid>).</para> + + <para>The MAC address uniquely identifies every network card + in existence. A typical MAC address looks like <hostid + role="mac">08:00:20:87:ef:d0</hostid>.</para> + </example> + </sect3> + + <sect3> + <title>Usernames</title> + + <note> + <title>&os; Extension</title> + + <para>These elements are part of the FreeBSD extension to + DocBook, and do not exist in the original DocBook + DTD.</para> + </note> + + <para>When you need to refer to a specific username, such as + <literal>root</literal> or <literal>bin</literal>, use + <sgmltag>username</sgmltag>.</para> + + <example> + <title><sgmltag>username</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>To carry out most system administration functions you + will need to be <username>root</username>.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>To carry out most system administration functions you + will need to be <username>root</username>.</para> + </example> + </sect3> + + <sect3> + <title>Describing <filename>Makefile</filename>s</title> + + <note> + <title>&os; Extension</title> + + <para>These elements are part of the FreeBSD extension to + DocBook, and do not exist in the original DocBook + DTD.</para> + </note> + + <para>Two elements exist to describe parts of + <filename>Makefile</filename>s, + <sgmltag>maketarget</sgmltag> and + <sgmltag>makevar</sgmltag>.</para> + + <para><sgmltag>maketarget</sgmltag> identifies a build target + exported by a <filename>Makefile</filename> that can be + given as a parameter to <command>make</command>. + <sgmltag>makevar</sgmltag> identifies a variable that can be + set (in the environment, on the <command>make</command> + command line, or within the <filename>Makefile</filename>) + to influence the process.</para> + + <example> + <title><sgmltag>maketarget</sgmltag> and + <sgmltag>makevar</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>Two common targets in a <filename>Makefile</filename> + are <maketarget>all</maketarget> and <maketarget>clean</maketarget>.</para> + +<para>Typically, invoking <maketarget>all</maketarget> will rebuild the + application, and invoking <maketarget>clean</maketarget> will remove + the temporary files (<filename>.o</filename> for example) created by + the build process.</para> + +<para><maketarget>clean</maketarget> may be controlled by a number of + variables, including <makevar>CLOBBER</makevar> and + <makevar>RECURSE</makevar>.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>Two common targets in a <filename>Makefile</filename> + are <maketarget>all</maketarget> and + <maketarget>clean</maketarget>.</para> + + <para>Typically, invoking <maketarget>all</maketarget> will + rebuild the application, and invoking + <maketarget>clean</maketarget> will remove the temporary + files (<filename>.o</filename> for example) created by the + build process.</para> + + <para><maketarget>clean</maketarget> may be controlled by a + number of variables, including <makevar>CLOBBER</makevar> + and <makevar>RECURSE</makevar>.</para> + </example> + </sect3> + + <sect3> + <title>Literal Text</title> + + <para>You will often need to include <quote>literal</quote> + text in the documentation. This is text that is excerpted + from another file, or which should be copied from the + documentation into another file verbatim.</para> + + <para>Some of the time, <sgmltag>programlisting</sgmltag> will + be sufficient to denote this text. + <sgmltag>programlisting</sgmltag> is not always appropriate, + particularly when you want to include a portion of a file + <quote>in-line</quote> with the rest of the + paragraph.</para> + + <para>On these occasions, use + <sgmltag>literal</sgmltag>.</para> + + <example> + <title><sgmltag>literal</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>The <literal>maxusers 10</literal> line in the kernel + configuration file determines the size of many system tables, and is + a rough guide to how many simultaneous logins the system will + support.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>The <literal>maxusers 10</literal> line in the kernel + configuration file determines the size of many system + tables, and is a rough guide to how many simultaneous + logins the system will support.</para> + </example> + </sect3> + + <sect3> + <title>Showing Items That the User <emphasis>Must</emphasis> + Fill In</title> + + <para>There will often be times when you want to show the user + what to do, or refer to a file, or command line, or similar, + where the user cannot simply copy the examples that you + provide, but must instead include some information + themselves.</para> + + <para><sgmltag>replaceable</sgmltag> is designed for this + eventuality. Use it <emphasis>inside</emphasis> other + elements to indicate parts of that element's content that + the user must replace.</para> + + <example> + <title><sgmltag>replaceable</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<screen>&prompt.user; <userinput>man <replaceable>command</replaceable></userinput></screen>]]></programlisting> + + <para>Appearance:</para> + + <informalexample> + <screen>&prompt.user; <userinput>man <replaceable>command</replaceable></userinput></screen> + </informalexample> + + <para><sgmltag>replaceable</sgmltag> can be used in many + different elements, including <sgmltag>literal</sgmltag>. + This example also shows that + <sgmltag>replaceable</sgmltag> should only be wrapped + around the content that the user <emphasis>is</emphasis> + meant to provide. The other content should be left + alone.</para> + + <para>Use:</para> + + <programlisting><![CDATA[<para>The <literal>maxusers <replaceable>n</replaceable></literal> + line in the kernel configuration file determines the size of many system + tables, and is a rough guide to how many simultaneous logins the system will + support.</para> + +<para>For a desktop workstation, <literal>32</literal> is a good value + for <replaceable>n</replaceable>.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>The + <literal>maxusers <replaceable>n</replaceable></literal> + line in the kernel configuration file determines the size + of many system tables, and is a rough guide to how many + simultaneous logins the system will support.</para> + + <para>For a desktop workstation, <literal>32</literal> is a + good value for <replaceable>n</replaceable>.</para> + </example> + </sect3> + + <sect3> + <title>Quoting System Errors</title> + + <para>You might want to show errors generated by FreeBSD. + Mark these with <sgmltag>errorname</sgmltag>. This + indicates the exact error that appears.</para> + + <example> + <title><sgmltag>errorname</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[ +<screen><errorname>Panic: cannot mount root</errorname></screen> ]]> +</programlisting> + + + <para>Appearance:</para> + + <informalexample> + <screen><errorname>Panic: cannot mount root</errorname></screen> + </informalexample> + </example> + </sect3> + </sect2> + + <sect2> + <title>Images</title> + + <important> + <para>Image support in the documentation is currently + extremely experimental. The mechanisms described here are + unlikely to change, but that is not guaranteed.</para> + + <para>You will also need to install the + <filename role="package">graphics/ImageMagick</filename> + port, which is used to convert between the different image + formats. This is a big port, and most of it is not + required. However, while we are working on the + <filename>Makefile</filename>s and other infrastructure it + makes things easier. This port is <emphasis>not</emphasis> + in the <filename role="package">textproc/docproj</filename> + meta port, you must install it by hand.</para> + + <para>The best example of what follows in practice is the + <filename>doc/en_US.ISO8859-1/articles/vm-design/</filename> + document. If you are unsure of the description that + follows, take a look at the files in that directory to see + how everything hangs together. Experiment with creating + different formatted versions of the document to see how the + image markup appears in the formatted output.</para> + </important> + + <sect3> + <title>Image Formats</title> + + <para>We currently support two formats for images. The format + you should use will depend on the nature of your + image.</para> + + <para>For images that are primarily vector based, such as + network diagrams, time lines, and similar, use Encapsulated + Postscript, and make sure that your images have the + <filename>.eps</filename> extension.</para> + + <para>For bitmaps, such as screen captures, use the Portable + Network Graphic format, and make sure that your images have + the <filename>.png</filename> extension.</para> + + <para>These are the <emphasis>only</emphasis> formats in which + images should be committed to the Subversion + repository.</para> + + <para>Use the right format for the right image. It is to be + expected that your documentation will have a mix of EPS and + PNG images. The <filename>Makefile</filename>s ensure that + the correct format image is chosen depending on the output + format that you use for your documentation. <emphasis>Do + not commit the same image to the repository in two different + formats</emphasis>.</para> + + <important> + <para>It is anticipated that the Documentation Project will + switch to using the Scalable Vector Graphic (SVG) format + for vector images. However, the current state of SVG + capable editing tools makes this impractical.</para> + </important> + </sect3> + + <sect3> + <title>Markup</title> + + <para>The markup for an image is relatively simple. First, + markup a <sgmltag>mediaobject</sgmltag>. The + <sgmltag>mediaobject</sgmltag> can contain other, more + specific objects. We are concerned with two, the + <sgmltag>imageobject</sgmltag> and the + <sgmltag>textobject</sgmltag>.</para> + + <para>You should include one <sgmltag>imageobject</sgmltag>, + and two <sgmltag>textobject</sgmltag> elements. The + <sgmltag>imageobject</sgmltag> will point to the name of the + image file that will be used (without the extension). The + <sgmltag>textobject</sgmltag> elements contain information + that will be presented to the user as well as, or instead + of, the image.</para> + + <para>There are two circumstances where this can + happen.</para> + + <itemizedlist> + <listitem> + <para>When the reader is viewing the documentation in + HTML. In this case, each image will need to have + associated alternate text to show the user, typically + whilst the image is loading, or if they hover the mouse + pointer over the image.</para> + </listitem> + + <listitem> + <para>When the reader is viewing the documentation in + plain text. In this case, each image should have an + ASCII art equivalent to show the user.</para> + </listitem> + </itemizedlist> + + <para>An example will probably make things easier to + understand. Suppose you have an image, called + <filename>fig1</filename>, that you want to include in the + document. This image is of a rectangle with an A inside it. + The markup for this would be as follows.</para> + + <programlisting><mediaobject> + <imageobject> + <imagedata fileref="fig1"> <co id="co-image-ext"/> + </imageobject> + + <textobject> + <literallayout class="monospaced">+---------------+ <co id="co-image-literal"/> +| A | ++---------------+</literallayout> + </textobject> + + <textobject> + <phrase>A picture</phrase> <co id="co-image-phrase"/> + </textobject> +</mediaobject></programlisting> + + <calloutlist> + <callout arearefs="co-image-ext"> + <para>Include an <sgmltag>imagedata</sgmltag> element + inside the <sgmltag>imageobject</sgmltag> element. The + <literal>fileref</literal> attribute should contain the + filename of the image to include, without the extension. + The stylesheets will work out which extension should be + added to the filename automatically.</para> + </callout> + + <callout arearefs="co-image-literal"> + + <para>The first <sgmltag>textobject</sgmltag> should + contain a <sgmltag>literallayout</sgmltag> element, + where the <literal>class</literal> attribute is set to + <literal>monospaced</literal>. This is your opportunity + to demonstrate your ASCII art skills. This content will + be used if the document is converted to plain + text.</para> + + <para>Notice how the first and last lines of the content + of the <sgmltag>literallayout</sgmltag> element butt up + next to the element's tags. This ensures no extraneous + white space is included.</para> + </callout> + + <callout arearefs="co-image-phrase"> + <para>The second <sgmltag>textobject</sgmltag> should + contain a single <sgmltag>phrase</sgmltag> element. The + contents of this will become the <literal>alt</literal> + attribute for the image when this document is converted + to HTML.</para> + </callout> + </calloutlist> + </sect3> + + <sect3> + <title><filename>Makefile</filename> Entries</title> + + <para>Your images must be listed in the + <filename>Makefile</filename> in the + <makevar>IMAGES</makevar> variable. This variable should + contain the name of all your <emphasis>source</emphasis> + images. For example, if you have created three figures, + <filename>fig1.eps</filename>, + <filename>fig2.png</filename>, + <filename>fig3.png</filename>, then your + <filename>Makefile</filename> should have lines like this in + it.</para> + + <programlisting>… +IMAGES= fig1.eps fig2.png fig3.png +…</programlisting> + + <para>or</para> + + <programlisting>… +IMAGES= fig1.eps +IMAGES+= fig2.png +IMAGES+= fig3.png +…</programlisting> + + <para>Again, the <filename>Makefile</filename> will work out + the complete list of images it needs to build your source + document, you only need to list the image files + <emphasis>you</emphasis> provided.</para> + </sect3> + + <sect3> + <title>Images and Chapters in Subdirectories</title> + + <para>You must be careful when you separate your documentation + into smaller files (see + <xref linkend="xml-primer-include-using-gen-entities"/>) in + different directories.</para> + + <para>Suppose you have a book with three chapters, and the + chapters are stored in their own directories, called + <filename>chapter1/chapter.xml</filename>, + <filename>chapter2/chapter.xml</filename>, and + <filename>chapter3/chapter.xml</filename>. If each chapter + has images associated with it, it is suggested to place + those images in each chapter's subdirectory + (<filename>chapter1/</filename>, + <filename>chapter2/</filename>, and + <filename>chapter3/</filename>).</para> + + <para>However, if you do this you must include the directory + names in the <makevar>IMAGES</makevar> variable in the + <filename>Makefile</filename>, <emphasis>and</emphasis> you + must include the directory name in the + <sgmltag>imagedata</sgmltag> element in your + document.</para> + + <para>For example, if you have + <filename>chapter1/fig1.png</filename>, then + <filename>chapter1/chapter.xml</filename> should + contain:</para> + + <programlisting><mediaobject> + <imageobject> + <imagedata fileref="chapter1/fig1"> <co id="co-image-dir"/> + </imageobject> + + … + +</mediaobject></programlisting> + + <calloutlist> + <callout arearefs="co-image-dir"> + <para>The directory name must be included in the + <literal>fileref</literal> attribute.</para> + </callout> + </calloutlist> + + <para>The <filename>Makefile</filename> must contain:</para> + + <programlisting>… +IMAGES= chapter1/fig1.png +…</programlisting> + + <para>Then everything should just work.</para> + </sect3> + </sect2> + + <sect2> + <title>Links</title> + + <note> + <para>Links are also in-line elements.</para> + </note> + + <sect3> + <title>Linking to Other Parts of the Same Document</title> + + <para>Linking within the same document requires you to specify + where you are linking from (i.e., the text the user will + click, or otherwise indicate, as the source of the link) and + where you are linking to (the link's destination).</para> + + <para>Each element within DocBook has an attribute called + <literal>id</literal>. You can place text in this attribute + to uniquely name the element it is attached to.</para> + + <para>This value will be used when you specify the link + source.</para> + + <para>Normally, you will only be linking to chapters or + sections, so you would add the <literal>id</literal> + attribute to these elements.</para> + + <example> + <title>Attribute <literal>id</literal> on Chapters and + Sections</title> + + <programlisting><![CDATA[<chapter id="chapter1"> + <title>Introduction</title> + + <para>This is the introduction. It contains a subsection, + which is identified as well.</para> + + <sect1 id="chapter1-sect1"> + <title>Sub-sect 1</title> + + <para>This is the subsection.</para> + </sect1> +</chapter>]]></programlisting> + </example> + + <para>Obviously, you should use more descriptive values. The + values must be unique within the document (i.e., not just + the file, but the document the file might be included in as + well). Notice how the <literal>id</literal> for the + subsection is constructed by appending text to the + <literal>id</literal> of the chapter. This helps to ensure + that they are unique.</para> + + <para>If you want to allow the user to jump into a specific + portion of the document (possibly in the middle of a + paragraph or an example), use <sgmltag>anchor</sgmltag>. + This element has no content, but takes an + <literal>id</literal> attribute.</para> + + <example> + <title><sgmltag>anchor</sgmltag></title> + + <programlisting><![CDATA[<para>This paragraph has an embedded + <anchor id="para1">link target in it. It will not show up in + the document.</para>]]></programlisting> + </example> + + <para>When you want to provide the user with a link they can + activate (probably by clicking) to go to a section of the + document that has an <literal>id</literal> attribute, you + can use either <sgmltag>xref</sgmltag> or + <sgmltag>link</sgmltag>.</para> + + <para>Both of these elements have a <literal>linkend</literal> + attribute. The value of this attribute should be the value + that you have used in a <literal>id</literal> attribute (it + does not matter if that value has not yet occurred in your + document; this will work for forward links as well as + backward links).</para> + + <para>If you use <sgmltag>xref</sgmltag> then you have no + control over the text of the link. It will be generated for + you.</para> + + <example> + <title>Using <sgmltag>xref</sgmltag></title> + + <para>Assume that this fragment appears somewhere in a + document that includes the <literal>id</literal> + example:</para> + + <programlisting><![CDATA[<para>More information can be found + in <xref linkend="chapter1"/>.</para> + +<para>More specific information can be found + in <xref linkend="chapter1-sect1"/>.</para>]]></programlisting> + + <para>The text of the link will be generated automatically, + and will look like (<emphasis>emphasized</emphasis> text + indicates the text that will be the link):</para> + + <blockquote> + <para>More information can be found in <emphasis>Chapter + One</emphasis>.</para> + + <para>More specific information can be found in + <emphasis>the section called Sub-Sect + 1</emphasis>.</para> + </blockquote> + </example> + + <para>Notice how the text from the link is derived from the + section title or the chapter number.</para> + + <note> + <para>This means that you <emphasis>cannot</emphasis> use + <sgmltag>xref</sgmltag> to link to an + <literal>id</literal> attribute on an + <sgmltag>anchor</sgmltag> element. The + <sgmltag>anchor</sgmltag> has no content, so the + <sgmltag>xref</sgmltag> cannot generate the text for the + link.</para> + </note> + + <para>If you want to control the text of the link then use + <sgmltag>link</sgmltag>. This element wraps content, and + the content will be used for the link.</para> + + <example> + <title>Using <sgmltag>link</sgmltag></title> + + <para>Assume that this fragment appears somewhere in a + document that includes the <literal>id</literal> + example.</para> + + <programlisting><![CDATA[<para>More information can be found in + <link linkend="chapter1">the first chapter</link>.</para> + +<para>More specific information can be found in + <link linkend="chapter1-sect1">this</link> section.</para>]]></programlisting> + + <para>This will generate the following + (<emphasis>emphasized</emphasis> text indicates the text + that will be the link):</para> + + <blockquote> + <para>More information can be found in <emphasis>the first + chapter</emphasis>.</para> + + <para>More specific information can be found in + <emphasis>this</emphasis> section.</para> + </blockquote> + </example> + + <note> + <para>That last one is a bad example. Never use words like + <quote>this</quote> or <quote>here</quote> as the source + for the link. The reader will need to hunt around the + surrounding context to see where the link is actually + taking them.</para> + </note> + + <note> + <para>You <emphasis>can</emphasis> use + <sgmltag>link</sgmltag> to include a link to an + <literal>id</literal> on an <sgmltag>anchor</sgmltag> + element, since the <sgmltag>link</sgmltag> content defines + the text that will be used for the link.</para> + </note> + </sect3> + + <sect3> + <title>Linking to Documents on the WWW</title> + + <para>Linking to external documents is much simpler, as long + as you know the URL of the document you want to link to. + Use <sgmltag>ulink</sgmltag>. The <literal>url</literal> + attribute is the URL of the page that the link points to, + and the content of the element is the text that will be + displayed for the user to activate.</para> + + <example> + <title><sgmltag>ulink</sgmltag></title> + + <para>Use:</para> + + <programlisting><![CDATA[<para>Of course, you could stop reading this document and + go to the <ulink url="&url.base;/index.html">FreeBSD + home page</ulink> instead.</para>]]></programlisting> + + <para>Appearance:</para> + + <para>Of course, you could stop reading this document and go + to the <ulink url="&url.base;/index.html">FreeBSD home + page</ulink> instead.</para> + </example> + </sect3> + </sect2> + </sect1> +</chapter> |