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Usermanual: clusters chapter, minor updates.

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Nathan Willis 2018-11-15 15:47:03 -06:00 committed by Khaled Hosny
parent 53ac46e974
commit 939220e57d
1 changed files with 16 additions and 9 deletions
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25
docs/usermanual-clusters.xml
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@ -30,20 +30,21 @@
<itemizedlist> <itemizedlist>
<listitem> <listitem>
<para> <para>
Correctly positioning the cursor between two characters that Correctly positioning the cursor within a shaped text run,
have combined into a single glyph by forming a ligature. even when characters have formed ligatures, composed or
decomposed, reordered, or undergone other shaping operations.
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
<para> <para>
Correctly highlighting a text selection that includes some, Correctly highlighting a text selection that includes some,
but not all, of the characters comprising a ligature. but not all, of the characters in a word.
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
<para> <para>
Applying text attributes (such as color or underlining) to Applying text attributes (such as color or underlining) to
part, but not all, of a composed base-and-mark combination. part, but not all, of a word.
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
@ -52,6 +53,12 @@
embedded text that can be fully extracted. embedded text that can be fully extracted.
</para> </para>
</listitem> </listitem>
<listitem>
<para>
Determining the mapping between input characters and output
glyphs, such as which glyphs are ligatures.
</para>
</listitem>
<listitem> <listitem>
<para> <para>
Performing line-breaking, justification, and other Performing line-breaking, justification, and other
@ -69,7 +76,7 @@
This cluster value is an arbitrary number; HarfBuzz uses it only This cluster value is an arbitrary number; HarfBuzz uses it only
to distinguish between clusters. Many client programs will use to distinguish between clusters. Many client programs will use
the index of each code point in the input text stream as the the index of each code point in the input text stream as the
cluster value, as a matter of convenience; the actual value does cluster value, for the sake of convenience; the actual value does
not matter. not matter.
</para> </para>
<para> <para>
@ -122,10 +129,10 @@
Level 1 differs from level 0 by not merging the Level 1 differs from level 0 by not merging the
clusters of marks and other modifier code points with the clusters of marks and other modifier code points with the
preceding "base" code point's cluster. By preserving the preceding "base" code point's cluster. By preserving the
cluster values of these marks and modifier code points, separate cluster values of these marks and modifier code
script shaping can perform additional operations that might points, script shapers can perform additional operations
lead to improved results (for example, reordering a sequence that might lead to improved results (for example, reordering
of marks). a sequence of marks).
</para> </para>
<para> <para>
Client programs can specify level 1 behavior for a buffer by Client programs can specify level 1 behavior for a buffer by