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   5 <title>Shaper selection: HarfBuzz Manual</title>
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  23 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
  24 <a name="shaping-shaper-selection"></a>Shaper selection</h2></div></div></div>
  25 <p>
  26       The basic version of <code class="function">hb_shape()</code> determines
  27       its shaping strategy based on examining the capabilities of the
  28       font file. OpenType font tables cause HarfBuzz to try the
  29       <code class="literal">ot</code> shaper, while AAT font tables cause HarfBuzz to try the
  30       <code class="literal">aat</code> shaper.
  31     </p>
  32 <p>
  33       In the real world, however, a font might include some unusual
  34       mix of tables, or one of the tables might simply be broken for
  35       the script you need to shape. So, sometimes, you might not
  36       want to rely on HarfBuzz's process for deciding what to do, and
  37       just tell <code class="function">hb_shape()</code> what you want it to try.
  38     </p>
  39 <p>
  40       <code class="function">hb_shape_full()</code> is an alternate shaping
  41       function that lets you supply a list of shapers for HarfBuzz to
  42       try, in order, when shaping your buffer. For example, if you
  43       have determined that HarfBuzz's attempts to work around broken
  44       tables gives you better results than the AAT shaper itself does,
  45       you might move the AAT shaper to the end of your list of
  46       preferences and call <code class="function">hb_shape_full()</code>
  47     </p>
  48 <pre class="programlisting">
  49       char *shaperprefs[3] = {"ot", "default", "aat"};
  50       ...
  51       hb_shape_full(font, buf, userfeatures, num_features, shaperprefs);
  52     </pre>
  53 <p>
  54       to get results you are happier with.
  55     </p>
  56 <p>
  57       You may also want to call
  58       <code class="function">hb_shape_list_shapers()</code> to get a list of
  59       the shapers that were built at compile time in your copy of HarfBuzz.
  60     </p>
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