<?xml version="1.0" encoding="latin1" ?>
<!DOCTYPE chapter SYSTEM "chapter.dtd">
<chapter>
<header>
<copyright>
<year>2000</year><year>2009</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
The contents of this file are subject to the Erlang Public License,
Version 1.1, (the "License"); you may not use this file except in
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Software distributed under the License is distributed on an "AS IS"
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</legalnotice>
<title>Fonts</title>
<prepared></prepared>
<docno></docno>
<date></date>
<rev></rev>
<file>gs_chapter5.xml</file>
</header>
<section>
<title>The Font Model</title>
<p>Text related objects can be handled with the font option <c><![CDATA[{font,Font}]]></c>. A <c><![CDATA[Font]]></c> is represented as a two or three tuple:</p>
<list type="bulleted">
<item><c><![CDATA[{Family,Size}]]></c></item>
<item><c><![CDATA[{Family,Style,Size}]]></c></item>
</list>
<p>Examples of fonts are: <c><![CDATA[{times,12}]]></c>, <c><![CDATA[{symbol,bold,18}]]></c>, <c><![CDATA[{courier,[bold,italic],6}]]></c>, <c><![CDATA[{screen,12}]]></c>.</p>
<p>The most important requirement with the font model is to ensure that there is always a "best possible" font present. For example, if an application tries to use the font <c><![CDATA[{times,17}]]></c> on a computer system which does not have this font available, the <c><![CDATA[gs]]></c> font model automatically substitutes <c><![CDATA[{times,16}]]></c>.</p>
<p>Note that GS requires that the following fonts are available if using an X-server display:</p>
<list type="bulleted">
<item>fixed</item>
<item>-*-courier-*</item>
<item>-*-times-*</item>
<item>-*-helvetica-*</item>
<item>-*-symbol-*</item>
<item>"-*-new century schoolbook-"</item>
<item>-*-screen-*</item>
</list>
<p>To find out which font is actually chosen by the <c><![CDATA[gs]]></c>, use the option <c><![CDATA[{choose_font,Font}]]></c>. For example, the following situation might occur:</p>
<pre><![CDATA[
1> <input>G=gs:start().</input>
{1,<0.20.0>}
2><input>gs:read(G,{choose_font,{times,38}}).</input>
{times,[],38}
3> <input>gs:read(G,{choose_font,{screen,italic,6}}).</input>
{courier,italic,6}
4>
]]></pre>
<p>When programming with fonts, it is often necessary to find the size of a string which uses a specific font. <c><![CDATA[{font_wh,Font}]]></c> returns the width and height of any string and any font. The following example illustrates its usage:</p>
<marker id="gs_fig6"></marker>
<image file="images/ex15.gif">
<icaption>Font Examples</icaption>
</image>
<codeinclude file="examples/ex15.erl" tag="" type="erl"></codeinclude>
</section>
</chapter>
