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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"><title>PangoEngineShape</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1"><link rel="start" href="index.html" title="Pango Reference Manual"><link rel="up" href="lowlevel.html" title="Low Level Functionality"><link rel="prev" href="PangoEngineLang.html" title="PangoEngineLang"><link rel="next" href="pango-Modules.html" title="Modules"><meta name="generator" content="GTK-Doc V1.6 (XML mode)"><link rel="stylesheet" href="style.css" type="text/css"><link rel="chapter" href="pango.html" title="Basic Pango Interfaces"><link rel="chapter" href="rendering.html" title="Rendering with Pango"><link rel="chapter" href="lowlevel.html" title="Low Level Functionality"><link rel="chapter" href="tools.html" title="Pango Tools"><link rel="index" href="ix01.html" title="Index"><link rel="index" href="ix02.html" title="Index of deprecated symbols"><link rel="index" href="ix03.html" title="Index of new symbols in 1.2"><link rel="index" href="ix04.html" title="Index of new symbols in 1.4"><link rel="index" href="ix05.html" title="Index of new symbols in 1.6"><link rel="index" href="ix06.html" title="Index of new symbols in 1.8"><link rel="index" href="ix07.html" title="Index of new symbols in 1.10"><link rel="index" href="ix08.html" title="Index of new symbols in 1.12"><link rel="index" href="ix09.html" title="Index of new symbols in 1.14"><link rel="index" href="ix10.html" title="Index of new symbols in 1.16"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2"><tr valign="middle"><td><a accesskey="p" href="PangoEngineLang.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td><td><a accesskey="u" href="lowlevel.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td><td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td><th width="100%" align="center">Pango Reference Manual</th><td><a accesskey="n" href="pango-Modules.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td></tr><tr><td colspan="5" class="shortcuts"><nobr><a href="#top_of_page" class="shortcut">Top</a>  |  <a href="#desc" class="shortcut">Description</a>  |  <a href="#object_hierarchy" class="shortcut">Object Hierarchy</a></nobr></td></tr></table><div class="refentry" lang="en"><a name="PangoEngineShape"></a><div class="titlepage"></div><div class="refnamediv"><table width="100%"><tr><td valign="top"><h2><span class="refentrytitle"><a name="top_of_page"></a>PangoEngineShape</span></h2><p>PangoEngineShape — Rendering-system dependent script engines</p></td><td valign="top" align="right"></td></tr></table></div><div class="refsynopsisdiv"><a name="synopsis"></a><h2>Synopsis</h2><pre class="synopsis"> <a href="PangoEngineShape.html#PangoEngineShape-struct">PangoEngineShape</a>; <a href="PangoEngineShape.html#PangoEngineShapeClass">PangoEngineShapeClass</a>;#define <a href="PangoEngineShape.html#PANGO-ENGINE-TYPE-SHAPE:CAPS">PANGO_ENGINE_TYPE_SHAPE</a>#define <a href="PangoEngineShape.html#PANGO-ENGINE-SHAPE-DEFINE-TYPE:CAPS">PANGO_ENGINE_SHAPE_DEFINE_TYPE</a> (name, prefix, class_init, instance_init)</pre></div><div class="refsect1" lang="en"><a name="object_hierarchy"></a><h2>Object Hierarchy</h2><pre class="synopsis"> <ahref="../gobject/gobject-The-Base-Object-Type.html#GObject">GObject</a> +----<a href="pango-Engines.html#PangoEngine">PangoEngine</a> +----PangoEngineShape</pre></div><div class="refsect1" lang="en"><a name="desc"></a><h2>Description</h2><p>The <em class="firstterm">shape engines</em> are rendering-system dependentengines that convert character strings into glyph strings.These engines are used in <a href="pango-Text-Processing.html#pango-shape"><code class="function">pango_shape()</code></a>.</p></div><div class="refsect1" lang="en"><a name="details"></a><h2>Details</h2><div class="refsect2" lang="en"><a name="id2939223"></a><h3><a name="PangoEngineShape-struct"></a>PangoEngineShape</h3><a class="indexterm" name="id2939235"></a><pre class="programlisting">typedef struct _PangoEngineShape PangoEngineShape;</pre><p>The <a href="PangoEngineShape.html" title="PangoEngineShape"><span class="type">PangoEngineShape</span></a> class is implemented by engines thatcustomize the rendering-system dependent part of thePango pipeline for a particular script or language.A <a href="PangoEngineShape.html" title="PangoEngineShape"><span class="type">PangoEngineShape</span></a> implementation is then specific to botha particular rendering system or group of rendering systemsand to a particular script. For instance, there is one<a href="PangoEngineShape.html" title="PangoEngineShape"><span class="type">PangoEngineShape</span></a> implementation to handle shaping Arabicfor Fontconfig-based backends.</p><p></p></div><hr><div class="refsect2" lang="en"><a name="id2939284"></a><h3><a name="PangoEngineShapeClass"></a>PangoEngineShapeClass</h3><a class="indexterm" name="id2939297"></a><pre class="programlisting">typedef struct { void (*script_shape) (PangoEngineShape *engine, PangoFont *font, const char *text, int length, const PangoAnalysis *analysis, PangoGlyphString *glyphs); PangoCoverageLevel (*covers) (PangoEngineShape *engine, PangoFont *font, PangoLanguage *language, gunichar wc);} PangoEngineShapeClass;</pre><p>Class structure for <a href="PangoEngineShape.html" title="PangoEngineShape"><span class="type">PangoEngineShape</span></a></p><p></p><div class="variablelist"><table border="0"><col align="left" valign="top"><tbody><tr><td><span class="term"><em class="structfield"><code>script_shape</code></em> ()</span></td><td> Given a font, a piece of text, and a <a href="pango-Text-Processing.html#PangoAnalysis"><span class="type">PangoAnalysis</span></a> structure, converts characters to glyphs and positions the resulting glyphs. The results are stored in the <a href="pango-Glyph-Storage.html#PangoGlyphString"><span class="type">PangoGlyphString</span></a> that is passed in. (The implementation should resize it appropriately using <a href="pango-Glyph-Storage.html#pango-glyph-string-set-size"><code class="function">pango_glyph_string_set_size()</code></a>). All fields of the <em class="parameter"><code>log_clusters</code></em> and <em class="parameter"><code>glyphs</code></em> array must be filled in, with the exception that Pango will automatically generate <code class="literal">glyphs->glyphs[i].attr.is_cluster_start</code> using the <em class="parameter"><code>log_clusters</code></em> array. Each input character must occur in one of the output logical clusters; if no rendering is desired for a character, this may involve inserting glyphs with the <a href="pango-Glyph-Storage.html#PangoGlyph"><span class="type">PangoGlyph</span></a> ID <a href="pango-Glyph-Storage.html#PANGO-GLYPH-EMPTY:CAPS"><span class="type">PANGO_GLYPH_EMPTY</span></a>, which is guaranteed never to render. If the shaping fails for any reason, the shaper should return with an empty (zero-size) glyph string. If the shaper has not set the size on the glyph string yet, simply returning signals the failure too.</td></tr><tr><td><span class="term"><em class="structfield"><code>covers</code></em> ()</span></td><td> Returns the characters that this engine can cover with a given font for a given language. If not overridden, the default implementation simply returns the coverage information for the font itself unmodified.</td></tr></tbody></table></div></div><hr><div class="refsect2" lang="en"><a name="id2939447"></a><h3><a name="PANGO-ENGINE-TYPE-SHAPE:CAPS"></a>PANGO_ENGINE_TYPE_SHAPE</h3><a class="indexterm" name="id2939460"></a><pre class="programlisting">#define PANGO_ENGINE_TYPE_SHAPE "PangoEngineShape"</pre><p>A string constant defining the engine typefor shaping engines.These engines derive from <a href="PangoEngineShape.html" title="PangoEngineShape"><span class="type">PangoEngineShape</span></a>.</p></div><hr><div class="refsect2" lang="en"><a name="id2939486"></a><h3><a name="PANGO-ENGINE-SHAPE-DEFINE-TYPE:CAPS"></a>PANGO_ENGINE_SHAPE_DEFINE_TYPE()</h3><a class="indexterm" name="id2939499"></a><pre class="programlisting">#define PANGO_ENGINE_SHAPE_DEFINE_TYPE(name, prefix, class_init, instance_init)</pre><p>Outputs the necessary code for GObject type registration for a<a href="PangoEngineShape.html" title="PangoEngineShape"><span class="type">PangoEngineShape</span></a> class defined in a module. Two static symbolsare defined.</p><p></p><pre class="programlisting"> static GType <em class="replaceable"><code>prefix</code></em>_type; static void <em class="replaceable"><code>prefix</code></em>_register_type (GTypeModule module);</pre><p></p><p>The <code class="function"><em class="replaceable"><code>prefix</code></em>, <code class="function">_register_type()</code></code>function should be called in your <a href="pango-Engines.html#script-engine-init"><code class="function">script_engine_init()</code></a> function foreach type that your module implements, and then your <a href="pango-Engines.html#script-engine-create"><code class="function">script_engine_create()</code></a>function can create instances of the object as follows:</p><p></p><div class="informalexample"><pre class="programlisting"> PangoEngine *engine = g_object_new (<em class="replaceable"><code>prefix</code></em>_type, NULL);</pre></div><p></p><div class="variablelist"><table border="0"><col align="left" valign="top"><tbody><tr><td><span class="term"><em class="parameter"><code>name</code></em> :</span></td><td> Name of the the type to register (for example:, <code class="literal">ArabicEngineFc</code></td></tr><tr><td><span class="term"><em class="parameter"><code>prefix</code></em> :</span></td><td> Prefix for symbols that will be defined (for example:, <code class="literal">arabic_engine_fc</code></td></tr><tr><td><span class="term"><em class="parameter"><code>class_init</code></em> :</span></td><td> Class initialization function for the new type, or <ahref="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a></td></tr><tr><td><span class="term"><em class="parameter"><code>instance_init</code></em> :</span></td><td> Instance initialization function for the new type, or <ahref="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a></td></tr></tbody></table></div></div></div></div></body></html>⌨️ 快捷键说明
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