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 <div class="chapter">
 <div class="titlepage"><div><div><h2 class="title">
 <a name="getting-started"></a>Getting started with HarfBuzz</h2></div></div></div>
 <div class="toc"><dl class="toc">
 <dt><span class="section"><a href="getting-started.html#id-1.2.4.2">An overview of the HarfBuzz shaping API</a></span></dt>
 <dt><span class="section"><a href="ch03s02.html">Terminology</a></span></dt>
 <dt><span class="section"><a href="ch03s03.html">A simple shaping example</a></span></dt>
 </dl></div>
 <div class="section">
 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
 <a name="id-1.2.4.2"></a>An overview of the HarfBuzz shaping API</h2></div></div></div>
 <p>
       The core of the HarfBuzz shaping API is the function
       <code class="function">hb_shape()</code>. This function takes a font, a
       buffer containing a string of Unicode codepoints and
       (optionally) a list of font features as its input. It replaces
       the codepoints in the buffer with the corresponding glyphs from
       the font, correctly ordered and positioned, and with any of the
       optional font features applied.
     </p>
 <p>
       In addition to holding the pre-shaping input (the Unicode
       codepoints that comprise the input string) and the post-shaping
       output (the glyphs and positions), a HarfBuzz buffer has several
       properties that affect shaping. The most important are the
       text-flow direction (e.g., left-to-right, right-to-left,
       top-to-bottom, or bottom-to-top), the script tag, and the
       language tag.
     </p>
 <p>
       For input string buffers, flags are available to denote when the
       buffer represents the beginning or end of a paragraph, to
       indicate whether or not to visibly render Unicode <code class="literal">Default
       Ignorable</code> codepoints, and to modify the cluster-merging
       behavior for the buffer. For shaped output buffers, the
       individual X and Y offsets and <code class="literal">advances</code>
       (the logical dimensions) of each glyph are
       accessible. HarfBuzz also flags glyphs as
       <code class="literal">UNSAFE_TO_BREAK</code> if breaking the string at
       that glyph (e.g., in a line-breaking or hyphenation process)
       would require re-shaping the text.
     </p>
 <p>
       HarfBuzz also provides methods to compare the contents of
       buffers, join buffers, normalize buffer contents, and handle
       invalid codepoints, as well as to determine the state of a
       buffer (e.g., input codepoints or output glyphs). Buffer
       lifecycles are managed and all buffers are reference-counted.
     </p>
 <p>
       Although the default <code class="function">hb_shape()</code> function is
       sufficient for most use cases, a variant is also provide that
       lets you specify which of HarfBuzz's shapers to use on a buffer.
     </p>
 <p>
       HarfBuzz can read TrueType fonts, TrueType collections, OpenType
       fonts, and OpenType collections. Functions are provided to query
       font objects about metrics, Unicode coverage, available tables and
       features, and variation selectors. Individual glyphs can also be
       queried for metrics, variations, and glyph names. OpenType
       variable fonts are supported, and HarfBuzz allows you to set
       variation-axis coordinates on font objects.
     </p>
 <p>
       HarfBuzz provides glue code to integrate with various other
       libraries, including FreeType, GObject, and CoreText. Support
       for integrating with Uniscribe and DirectWrite is experimental
       at present.
     </p>
 </div>
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	<title>Getting started with HarfBuzz: 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">
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	<div class="chapter">
	<div class="titlepage"><div><div><h2 class="title">
	<a name="getting-started"></a>Getting started with HarfBuzz</h2></div></div></div>
	<div class="toc"><dl class="toc">
	<dt><span class="section"><a href="getting-started.html#id-1.2.4.2">An overview of the HarfBuzz shaping API</a></span></dt>
	<dt><span class="section"><a href="ch03s02.html">Terminology</a></span></dt>
	<dt><span class="section"><a href="ch03s03.html">A simple shaping example</a></span></dt>
	</dl></div>
	<div class="section">
	<div class="titlepage"><div><div><h2 class="title" style="clear: both">
	<a name="id-1.2.4.2"></a>An overview of the HarfBuzz shaping API</h2></div></div></div>
	<p>
	The core of the HarfBuzz shaping API is the function
	<code class="function">hb_shape()</code>. This function takes a font, a
	buffer containing a string of Unicode codepoints and
	(optionally) a list of font features as its input. It replaces
	the codepoints in the buffer with the corresponding glyphs from
	the font, correctly ordered and positioned, and with any of the
	optional font features applied.
	</p>
	<p>
	In addition to holding the pre-shaping input (the Unicode
	codepoints that comprise the input string) and the post-shaping
	output (the glyphs and positions), a HarfBuzz buffer has several
	properties that affect shaping. The most important are the
	text-flow direction (e.g., left-to-right, right-to-left,
	top-to-bottom, or bottom-to-top), the script tag, and the
	language tag.
	</p>
	<p>
	For input string buffers, flags are available to denote when the
	buffer represents the beginning or end of a paragraph, to
	indicate whether or not to visibly render Unicode <code class="literal">Default
	Ignorable</code> codepoints, and to modify the cluster-merging
	behavior for the buffer. For shaped output buffers, the
	individual X and Y offsets and <code class="literal">advances</code>
	(the logical dimensions) of each glyph are
	accessible. HarfBuzz also flags glyphs as
	<code class="literal">UNSAFE_TO_BREAK</code> if breaking the string at
	that glyph (e.g., in a line-breaking or hyphenation process)
	would require re-shaping the text.
	</p>
	<p>
	HarfBuzz also provides methods to compare the contents of
	buffers, join buffers, normalize buffer contents, and handle
	invalid codepoints, as well as to determine the state of a
	buffer (e.g., input codepoints or output glyphs). Buffer
	lifecycles are managed and all buffers are reference-counted.
	</p>
	<p>
	Although the default <code class="function">hb_shape()</code> function is
	sufficient for most use cases, a variant is also provide that
	lets you specify which of HarfBuzz's shapers to use on a buffer.
	</p>
	<p>
	HarfBuzz can read TrueType fonts, TrueType collections, OpenType
	fonts, and OpenType collections. Functions are provided to query
	font objects about metrics, Unicode coverage, available tables and
	features, and variation selectors. Individual glyphs can also be
	queried for metrics, variations, and glyph names. OpenType
	variable fonts are supported, and HarfBuzz allows you to set
	variation-axis coordinates on font objects.
	</p>
	<p>
	HarfBuzz provides glue code to integrate with various other
	libraries, including FreeType, GObject, and CoreText. Support
	for integrating with Uniscribe and DirectWrite is experimental
	at present.
	</p>
	</div>
	</div>
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	<hr>Generated by GTK-Doc V1.25</div>
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