Mini Shell

Direktori : /usr/share/gtk-doc/html/harfbuzz/
Upload File :
Current File : //usr/share/gtk-doc/html/harfbuzz/object-model.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>The HarfBuzz object model: HarfBuzz Manual</title>
<meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
<link rel="home" href="index.html" title="HarfBuzz Manual">
<link rel="up" href="pt01.html" title="Part I. User's manual">
<link rel="prev" href="aat-shaping.html" title="AAT shaping">
<link rel="next" href="object-model-object-types.html" title="Objects in HarfBuzz">
<meta name="generator" content="GTK-Doc V1.32 (XML mode)">
<link rel="stylesheet" href="style.css" type="text/css">
</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="5"><tr valign="middle">
<td width="100%" align="left" class="shortcuts"></td>
<td><a accesskey="h" href="index.html"><img src="home.png" width="16" height="16" border="0" alt="Home"></a></td>
<td><a accesskey="u" href="pt01.html"><img src="up.png" width="16" height="16" border="0" alt="Up"></a></td>
<td><a accesskey="p" href="aat-shaping.html"><img src="left.png" width="16" height="16" border="0" alt="Prev"></a></td>
<td><a accesskey="n" href="object-model-object-types.html"><img src="right.png" width="16" height="16" border="0" alt="Next"></a></td>
</tr></table>
<div class="chapter">
<div class="titlepage"><div><div><h2 class="title">
<a name="object-model"></a>The HarfBuzz object model</h2></div></div></div>
<div class="toc"><dl class="toc">
<dt><span class="section"><a href="object-model.html#object-model-intro">An overview of data types in HarfBuzz</a></span></dt>
<dt><span class="section"><a href="object-model-object-types.html">Objects in HarfBuzz</a></span></dt>
<dt><span class="section"><a href="object-model-lifecycle.html">Object lifecycle management</a></span></dt>
<dt><span class="section"><a href="object-model-user-data.html">User data</a></span></dt>
<dt><span class="section"><a href="object-model-blobs.html">Blobs</a></span></dt>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="object-model-intro"></a>An overview of data types in HarfBuzz</h2></div></div></div>
<p>
      HarfBuzz features two kinds of data types: non-opaque,
      pass-by-value types and opaque, heap-allocated types.  This kind
      of separation is common in C libraries that have to provide
      API/ABI compatibility (almost) indefinitely. 
    </p>
<p>
      <span class="emphasis"><em>Value types:</em></span> The non-opaque, pass-by-value
      types include integer types, enums, and small structs.  Exposing
      a struct in the public API makes it impossible to expand the
      struct in the future. As such, exposing structs is reserved for
      cases where it’s extremely inefficient to do otherwise.
    </p>
<p>
      In HarfBuzz, several structs, like <code class="literal">hb_glyph_info_t</code> and
      <code class="literal">hb_glyph_position_t</code>, fall into that efficiency-sensitive
      category and are non-opaque.
    </p>
<p>
      For all non-opaque structs where future extensibility may be
      necessary, reserved members are included to hold space for
      possible future members.  As such, it’s important to provide
      <code class="function">equal()</code>, and <code class="function">hash()</code>
      methods for such structs, allowing users of the API do
      effectively deal with the type without having to 
      adapt their code to future changes. 
    </p>
<p>
      Important value types provided by HarfBuzz include the structs
      for working with Unicode code points, glyphs, and tags for font
      tables and features, as well as the enums for many Unicode and
      OpenType properties.
    </p>
</div>
</div>
<div class="footer">
<hr>Generated by GTK-Doc V1.32</div>
</body>
</html>

Zerion Mini Shell 1.0