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<div class="sect1">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="reordering-in-levels-0-and-1"></a>Reordering in levels 0 and 1</h2></div></div></div>
<p>
Another common operation in the more complex shapers is when things
reorder. In those cases, to maintain monotone clusters, HB merges
the clusters of everything in the reordering sequence. For example,
let's again start with the character sequence:
</p>
<pre class="programlisting">
A,B,C,D,E
0,1,2,3,4
</pre>
<p>
If <code class="literal">D</code> is reordered before <code class="literal">B</code>,
then the <code class="literal">B</code>, <code class="literal">C</code>, and
<code class="literal">D</code> clusters merge, and we get:
</p>
<pre class="programlisting">
A,D,B,C,E
0,1,1,1,4
</pre>
<p>
This is clearly not ideal, but it is the only sensible way to
maintain monotone indices and retain the true relationship between
glyphs and characters.
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