docs/html/buffers-language-script-and-direction.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
   2 <html>
   3 <head>
   4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   5 <title>HarfBuzz Manual: Buffers, language, script and direction</title>
   6 <meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
   7 <link rel="home" href="index.html" title="HarfBuzz Manual">
   8 <link rel="up" href="pt01.html" title="Part I. User's manual">
   9 <link rel="prev" href="hello-harfbuzz.html" title="Hello, Harfbuzz">
  10 <link rel="next" href="adding-text-to-the-buffer.html" title="Adding text to the buffer">
  11 <meta name="generator" content="GTK-Doc V1.20 (XML mode)">
  12 <link rel="stylesheet" href="style.css" type="text/css">
  13 </head>
  14 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
  15 <table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="10"><tr valign="middle">
  16 <td width="100%" align="left" class="shortcuts"></td>
  17 <td><a accesskey="h" href="index.html"><img src="home.png" width="16" height="16" border="0" alt="Home"></a></td>
  18 <td><a accesskey="u" href="pt01.html"><img src="up.png" width="16" height="16" border="0" alt="Up"></a></td>
  19 <td><a accesskey="p" href="hello-harfbuzz.html"><img src="left.png" width="16" height="16" border="0" alt="Prev"></a></td>
  20 <td><a accesskey="n" href="adding-text-to-the-buffer.html"><img src="right.png" width="16" height="16" border="0" alt="Next"></a></td>
  21 </tr></table>
  22 <div class="chapter">
  23 <div class="titlepage"><div><div><h2 class="title">
  24 <a name="buffers-language-script-and-direction"></a>Buffers, language, script and direction</h2></div></div></div>
  25 <div class="toc"><dl class="toc">
  26 <dt><span class="section"><a href="buffers-language-script-and-direction.html#creating-and-destroying-buffers">Creating and destroying buffers</a></span></dt>
  27 <dt><span class="section"><a href="adding-text-to-the-buffer.html">Adding text to the buffer</a></span></dt>
  28 <dt><span class="section"><a href="setting-buffer-properties.html">Setting buffer properties</a></span></dt>
  29 <dt><span class="section"><a href="what-about-the-other-scripts.html">What about the other scripts?</a></span></dt>
  30 <dt><span class="section"><a href="customizing-unicode-functions.html">Customizing Unicode functions</a></span></dt>
  31 </dl></div>
  32 <p>
  33     The input to Harfbuzz is a series of Unicode characters, stored in a
  34     buffer. In this chapter, we'll look at how to set up a buffer with
  35     the text that we want and then customize the properties of the
  36     buffer.
  37   </p>
  38 <div class="section">
  39 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
  40 <a name="creating-and-destroying-buffers"></a>Creating and destroying buffers</h2></div></div></div>
  41 <p>
  42       As we saw in our initial example, a buffer is created and
  43       initialized with <code class="literal">hb_buffer_create()</code>. This
  44       produces a new, empty buffer object, instantiated with some
  45       default values and ready to accept your Unicode strings.
  46     </p>
  47 <p>
  48       Harfbuzz manages the memory of objects that it creates (such as
  49       buffers), so you don't have to. When you have finished working on
  50       a buffer, you can call <code class="literal">hb_buffer_destroy()</code>:
  51     </p>
  52 <pre class="programlisting">
  53   hb_buffer_t *buffer = hb_buffer_create();
  54   ...
  55   hb_buffer_destroy(buffer);
  56 </pre>
  57 <p>
  58       This will destroy the object and free its associated memory -
  59       unless some other part of the program holds a reference to this
  60       buffer. If you acquire a Harfbuzz buffer from another subsystem
  61       and want to ensure that it is not garbage collected by someone
  62       else destroying it, you should increase its reference count:
  63     </p>
  64 <pre class="programlisting">
  65 void somefunc(hb_buffer_t *buffer) {
  66   buffer = hb_buffer_reference(buffer);
  67   ...
  68 </pre>
  69 <p>
  70       And then decrease it once you're done with it:
  71     </p>
  72 <pre class="programlisting">
  73   hb_buffer_destroy(buffer);
  74 }
  75 </pre>
  76 <p>
  77       To throw away all the data in your buffer and start from scratch,
  78       call <code class="literal">hb_buffer_reset(buffer)</code>. If you want to
  79       throw away the string in the buffer but keep the options, you can
  80       instead call <code class="literal">hb_buffer_clear_contents(buffer)</code>.
  81     </p>
  82 </div>
  83 </div>
  84 <div class="footer">
  85 <hr>
  86           Generated by GTK-Doc V1.20</div>
  87 </body>
  88 </html>