opentype.xml

Pango is a library for layout and rendering of text, with an emphasis on internationalization. Pang

  gushort  ligID;
  gushort  property_cache;    /* Internal */
} PangoOTGlyph;
</programlisting>
<para>
The <link linkend="PangoOTGlyph"><type>PangoOTGlyph</type></link> structure represents a single glyph together with
information used for OpenType layout processing of the glyph.
It contains the following fields.
</para><variablelist role="struct">
<varlistentry>
<term><link linkend="guint">guint</link>&nbsp;<structfield>glyph</structfield>;</term>
<listitem><simpara>the glyph itself.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="guint">guint</link>&nbsp;<structfield>properties</structfield>;</term>
<listitem><simpara>the properties value, identifying which features should be
	     applied on this glyph.  See <link linkend="pango-ruleset-add-feature"><function>pango_ruleset_add_feature()</function></link>.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="guint">guint</link>&nbsp;<structfield>cluster</structfield>;</term>
<listitem><simpara>the cluster that this glyph belongs to.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="gushort">gushort</link>&nbsp;<structfield>component</structfield>;</term>
<listitem><simpara>a component value, set by the OpenType layout engine.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="gushort">gushort</link>&nbsp;<structfield>ligID</structfield>;</term>
<listitem><simpara>a ligature index value, set by the OpenType layout engine.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="gushort">gushort</link>&nbsp;<structfield>property_cache</structfield>;</term>
<listitem><simpara>for internal use.

</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2 id="PangoOTRuleset-struct" role="struct">
<title>PangoOTRuleset</title>
<indexterm zone="PangoOTRuleset-struct"><primary>PangoOTRuleset</primary></indexterm><programlisting>typedef struct _PangoOTRuleset PangoOTRuleset;</programlisting>
<para>
The <link linkend="PangoOTRuleset"><type>PangoOTRuleset</type></link> structure holds a
set of features selected from the tables in an OpenType font.
(A feature is an operation such as adjusting glyph positioning
that should be applied to a text feature such as a certain
type of accent.) A <link linkend="PangoOTRuleset"><type>PangoOTRuleset</type></link>
is created with <link linkend="pango-ot-ruleset-new"><function>pango_ot_ruleset_new()</function></link>, features are added
to it with <link linkend="pango-ot-ruleset-add-feature"><function>pango_ot_ruleset_add_feature()</function></link>, then it is
applied to a <link linkend="PangoGlyphString"><type>PangoGlyphString</type></link> with <link linkend="pango-ot-ruleset-shape"><function>pango_ot_ruleset_shape()</function></link>.
</para></refsect2>
<refsect2 id="PangoOTRulesetDescription" role="struct" condition="since:1.18">
<title>PangoOTRulesetDescription</title>
<indexterm zone="PangoOTRulesetDescription" role="1.18"><primary>PangoOTRulesetDescription</primary></indexterm><programlisting>typedef struct {
  PangoScript               script;
  PangoLanguage            *language;
  const PangoOTFeatureMap  *static_gsub_features;
  guint                   n_static_gsub_features;
  const PangoOTFeatureMap  *static_gpos_features;
  guint                   n_static_gpos_features;
  const PangoOTFeatureMap  *other_features;
  guint                   n_other_features;
} PangoOTRulesetDescription;
</programlisting>
<para>
The <link linkend="PangoOTRuleset"><type>PangoOTRuleset</type></link> structure holds all the information needed
to build a complete <link linkend="PangoOTRuleset"><type>PangoOTRuleset</type></link> from an OpenType font.
The main use of this struct is to act as the key for a per-font
hash of rulesets.  The user populates a ruleset description and
gets the ruleset using <link linkend="pango-ot-ruleset-get-for-description"><function>pango_ot_ruleset_get_for_description()</function></link>
or create a new one using <link linkend="pango-ot-ruleset-new-from-description"><function>pango_ot_ruleset_new_from_description()</function></link>.
</para><variablelist role="struct">
<varlistentry>
<term><link linkend="PangoScript">PangoScript</link>&nbsp;<structfield>script</structfield>;</term>
<listitem><simpara>a <link linkend="PangoScript"><type>PangoScript</type></link>.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="PangoLanguage">PangoLanguage</link>&nbsp;*<structfield>language</structfield>;</term>
<listitem><simpara>a <link linkend="PangoLanguage"><type>PangoLanguage</type></link>.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term>const&nbsp;<link linkend="PangoOTFeatureMap">PangoOTFeatureMap</link>&nbsp;*<structfield>static_gsub_features</structfield>;</term>
<listitem><simpara>static map of GSUB features, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="guint">guint</link>&nbsp;<structfield>n_static_gsub_features</structfield>;</term>
<listitem><simpara>length of <parameter>static_gsub_features</parameter>, or 0.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term>const&nbsp;<link linkend="PangoOTFeatureMap">PangoOTFeatureMap</link>&nbsp;*<structfield>static_gpos_features</structfield>;</term>
<listitem><simpara>static map of GPOS features, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="guint">guint</link>&nbsp;<structfield>n_static_gpos_features</structfield>;</term>
<listitem><simpara>length of <parameter>static_gpos_features</parameter>, or 0.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term>const&nbsp;<link linkend="PangoOTFeatureMap">PangoOTFeatureMap</link>&nbsp;*<structfield>other_features</structfield>;</term>
<listitem><simpara>map of extra features to add to both GSUB and GPOS, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>.
                 Unlike the static maps, this pointer need not live beyond
		 the life of function calls taking this struct.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="guint">guint</link>&nbsp;<structfield>n_other_features</structfield>;</term>
<listitem><simpara>length of <parameter>other_features</parameter>, or 0.
</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since 1.18

</para></refsect2>
<refsect2 id="PangoOTTableType" role="enum">
<title>enum PangoOTTableType</title>
<indexterm zone="PangoOTTableType"><primary>PangoOTTableType</primary></indexterm><programlisting>typedef enum
{
  PANGO_OT_TABLE_GSUB,
  PANGO_OT_TABLE_GPOS
} PangoOTTableType;
</programlisting>
<para>
The <type>PangoOTTableType</type> enumeration values are used to
identify the various OpenType tables in the
<function>pango_ot_info_*</function> functions.
</para><variablelist role="enum">
<varlistentry id="PANGO-OT-TABLE-GSUB:CAPS" role="constant">
<term><literal>PANGO_OT_TABLE_GSUB</literal></term>
<listitem><simpara>The GSUB table.
</simpara></listitem>
</varlistentry>
<varlistentry id="PANGO-OT-TABLE-GPOS:CAPS" role="constant">
<term><literal>PANGO_OT_TABLE_GPOS</literal></term>
<listitem><simpara>The GPOS table.

</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2 id="PangoOTFeatureMap" role="struct" condition="since:1.18">
<title>PangoOTFeatureMap</title>
<indexterm zone="PangoOTFeatureMap" role="1.18"><primary>PangoOTFeatureMap</primary></indexterm><programlisting>typedef struct {
  char     feature_name[5];
  gulong   property_bit;
} PangoOTFeatureMap;
</programlisting>
<para>
The <type>PangoOTFeatureMap</type> typedef is used to represent an OpenType
feature with the property bit associated with it.  The feature tag is
represented as a char array instead of a <link linkend="PangoOTTag"><type>PangoOTTag</type></link> for convenience.
</para><variablelist role="struct">
<varlistentry>
<term><link linkend="char">char</link>&nbsp;<structfield>feature_name</structfield>[5];</term>
<listitem><simpara>feature tag in represented as four-letter ASCII string.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="gulong">gulong</link>&nbsp;<structfield>property_bit</structfield>;</term>
<listitem><simpara>the property bit to use for this feature.  See
	       <link linkend="pango-ot-ruleset-add-feature"><function>pango_ot_ruleset_add_feature()</function></link> for details.
</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since 1.18

</para></refsect2>
<refsect2 id="PANGO-OT-TAG-MAKE:CAPS" role="macro">
<title>PANGO_OT_TAG_MAKE()</title>
<indexterm zone="PANGO-OT-TAG-MAKE:CAPS"><primary>PANGO_OT_TAG_MAKE</primary></indexterm><programlisting>#define PANGO_OT_TAG_MAKE(c1,c2,c3,c4)		((PangoOTTag) FT_MAKE_TAG (c1, c2, c3, c4))
</programlisting>
<para>
Creates a <link linkend="PangoOTTag"><type>PangoOTTag</type></link> from four characters.  This is similar and
compatible with the <function><link linkend="FT-MAKE-TAG:CAPS"><function>FT_MAKE_TAG()</function></link></function> macro from
FreeType.
</para><variablelist role="params">
<varlistentry><term><parameter>c1</parameter>&nbsp;:</term>
<listitem><simpara>First character.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>c2</parameter>&nbsp;:</term>
<listitem><simpara>Second character.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>c3</parameter>&nbsp;:</term>
<listitem><simpara>Third character.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>c4</parameter>&nbsp;:</term>