opentype.xml

GTK+-2.0源码之pango-1.15.6.tar.gz

<refentry id="pango-OpenType-Font-Handling">
<refmeta>
<refentrytitle id="top_of_page">OpenType Font Handling</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>PANGO Library</refmiscinfo>
</refmeta>

<refnamediv>
<refname>OpenType Font Handling</refname>
<refpurpose>Obtaining information from OpenType tables</refpurpose>
<!--[<xref linkend="desc" endterm="desc.title"/>]-->
</refnamediv>

<refsynopsisdiv id="synopsis">
<title id="synopsis.title">Synopsis</title>

<synopsis>



typedef     <link linkend="PangoOTTag">PangoOTTag</link>;
            <link linkend="PangoOTInfo">PangoOTInfo</link>;
            <link linkend="PangoOTBuffer">PangoOTBuffer</link>;
            <link linkend="PangoOTGlyph">PangoOTGlyph</link>;
            <link linkend="PangoOTRuleset">PangoOTRuleset</link>;
enum        <link linkend="PangoOTTableType">PangoOTTableType</link>;
#define     <link linkend="PANGO-OT-ALL-GLYPHS:CAPS">PANGO_OT_ALL_GLYPHS</link>
#define     <link linkend="PANGO-OT-DEFAULT-LANGUAGE:CAPS">PANGO_OT_DEFAULT_LANGUAGE</link>
<link linkend="PangoOTInfo">PangoOTInfo</link>* <link linkend="pango-ot-info-get">pango_ot_info_get</link>              (<link linkend="FT-Face">FT_Face</link> face);
<link linkend="gboolean">gboolean</link>    <link linkend="pango-ot-info-find-script">pango_ot_info_find_script</link>       (<link linkend="PangoOTInfo">PangoOTInfo</link> *info,
                                             <link linkend="PangoOTTableType">PangoOTTableType</link> table_type,
                                             <link linkend="PangoOTTag">PangoOTTag</link> script_tag,
                                             <link linkend="guint">guint</link> *script_index);
<link linkend="gboolean">gboolean</link>    <link linkend="pango-ot-info-find-language">pango_ot_info_find_language</link>     (<link linkend="PangoOTInfo">PangoOTInfo</link> *info,
                                             <link linkend="PangoOTTableType">PangoOTTableType</link> table_type,
                                             <link linkend="guint">guint</link> script_index,
                                             <link linkend="PangoOTTag">PangoOTTag</link> language_tag,
                                             <link linkend="guint">guint</link> *language_index,
                                             <link linkend="guint">guint</link> *required_feature_index);
<link linkend="gboolean">gboolean</link>    <link linkend="pango-ot-info-find-feature">pango_ot_info_find_feature</link>      (<link linkend="PangoOTInfo">PangoOTInfo</link> *info,
                                             <link linkend="PangoOTTableType">PangoOTTableType</link> table_type,
                                             <link linkend="PangoOTTag">PangoOTTag</link> feature_tag,
                                             <link linkend="guint">guint</link> script_index,
                                             <link linkend="guint">guint</link> language_index,
                                             <link linkend="guint">guint</link> *feature_index);
<link linkend="PangoOTTag">PangoOTTag</link>* <link linkend="pango-ot-info-list-scripts">pango_ot_info_list_scripts</link>      (<link linkend="PangoOTInfo">PangoOTInfo</link> *info,
                                             <link linkend="PangoOTTableType">PangoOTTableType</link> table_type);
<link linkend="PangoOTTag">PangoOTTag</link>* <link linkend="pango-ot-info-list-languages">pango_ot_info_list_languages</link>    (<link linkend="PangoOTInfo">PangoOTInfo</link> *info,
                                             <link linkend="PangoOTTableType">PangoOTTableType</link> table_type,
                                             <link linkend="guint">guint</link> script_index,
                                             <link linkend="PangoOTTag">PangoOTTag</link> language_tag);
<link linkend="PangoOTTag">PangoOTTag</link>* <link linkend="pango-ot-info-list-features">pango_ot_info_list_features</link>     (<link linkend="PangoOTInfo">PangoOTInfo</link> *info,
                                             <link linkend="PangoOTTableType">PangoOTTableType</link> table_type,
                                             <link linkend="PangoOTTag">PangoOTTag</link> tag,
                                             <link linkend="guint">guint</link> script_index,
                                             <link linkend="guint">guint</link> language_index);
<link linkend="PangoOTBuffer">PangoOTBuffer</link>* <link linkend="pango-ot-buffer-new">pango_ot_buffer_new</link>          (<link linkend="PangoFcFont">PangoFcFont</link> *font);
<link linkend="void">void</link>        <link linkend="pango-ot-buffer-destroy">pango_ot_buffer_destroy</link>         (<link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer);
<link linkend="void">void</link>        <link linkend="pango-ot-buffer-clear">pango_ot_buffer_clear</link>           (<link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer);
<link linkend="void">void</link>        <link linkend="pango-ot-buffer-add-glyph">pango_ot_buffer_add_glyph</link>       (<link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer,
                                             <link linkend="guint">guint</link> glyph,
                                             <link linkend="guint">guint</link> properties,
                                             <link linkend="guint">guint</link> cluster);
<link linkend="void">void</link>        <link linkend="pango-ot-buffer-set-rtl">pango_ot_buffer_set_rtl</link>         (<link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer,
                                             <link linkend="gboolean">gboolean</link> rtl);
<link linkend="void">void</link>        <link linkend="pango-ot-buffer-set-zero-width-marks">pango_ot_buffer_set_zero_width_marks</link>
                                            (<link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer,
                                             <link linkend="gboolean">gboolean</link> zero_width_marks);
<link linkend="void">void</link>        <link linkend="pango-ot-buffer-get-glyphs">pango_ot_buffer_get_glyphs</link>      (<link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer,
                                             <link linkend="PangoOTGlyph">PangoOTGlyph</link> **glyphs,
                                             <link linkend="int">int</link> *n_glyphs);
<link linkend="void">void</link>        <link linkend="pango-ot-buffer-output">pango_ot_buffer_output</link>          (<link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer,
                                             <link linkend="PangoGlyphString">PangoGlyphString</link> *glyphs);
<link linkend="PangoOTRuleset">PangoOTRuleset</link>* <link linkend="pango-ot-ruleset-new">pango_ot_ruleset_new</link>        (<link linkend="PangoOTInfo">PangoOTInfo</link> *info);
<link linkend="void">void</link>        <link linkend="pango-ot-ruleset-add-feature">pango_ot_ruleset_add_feature</link>    (<link linkend="PangoOTRuleset">PangoOTRuleset</link> *ruleset,
                                             <link linkend="PangoOTTableType">PangoOTTableType</link> table_type,
                                             <link linkend="guint">guint</link> feature_index,
                                             <link linkend="gulong">gulong</link> property_bit);
<link linkend="void">void</link>        <link linkend="pango-ot-ruleset-substitute">pango_ot_ruleset_substitute</link>     (<link linkend="PangoOTRuleset">PangoOTRuleset</link> *ruleset,
                                             <link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer);
<link linkend="void">void</link>        <link linkend="pango-ot-ruleset-position">pango_ot_ruleset_position</link>       (<link linkend="PangoOTRuleset">PangoOTRuleset</link> *ruleset,
                                             <link linkend="PangoOTBuffer">PangoOTBuffer</link> *buffer);
</synopsis>
</refsynopsisdiv>









<refsect1 id="desc">
<title id="desc.title">Description</title>
<para>
Functions and macros in this section are used to implement the OpenType Layout
features and algorithms.  These are mostly useful when writing Fontconfig-based
shaping engines
</para>
</refsect1>

<refsect1 id="details">
<title id="details.title">Details</title>
<refsect2>
<title><anchor id="PangoOTTag" role="typedef"/>PangoOTTag</title>
<indexterm><primary>PangoOTTag</primary></indexterm><programlisting>typedef guint32  PangoOTTag;
</programlisting>
<para>
The <type>PangoOTTag</type> typedef is used to represent TrueType and OpenType
four letter tags inside Pango. Use the <function><link linkend="FT-MAKE-TAG:CAPS"><function>FT_MAKE_TAG()</function></link></function> macro
defined in the FreeType2 header <filename>freetype/freetype.h</filename> to 
create <type>PangoOTTag</type>s manually.
</para></refsect2>
<refsect2>
<title><anchor id="PangoOTInfo" role="struct"/>PangoOTInfo</title>
<indexterm><primary>PangoOTInfo</primary></indexterm><programlisting>typedef struct _PangoOTInfo PangoOTInfo;</programlisting>
<para>
The <link linkend="PangoOTInfo"><type>PangoOTInfo</type></link> struct contains the various 
tables associated with an OpenType font. It contains only private fields and
should only be accessed via the <function>pango_ot_info_*</function> functions
which are documented below. To obtain a <link linkend="PangoOTInfo"><type>PangoOTInfo</type></link>,
use <link linkend="pango-ot-info-new"><function>pango_ot_info_new()</function></link>.
</para></refsect2>
<refsect2>
<title><anchor id="PangoOTBuffer" role="struct"/>PangoOTBuffer</title>
<indexterm><primary>PangoOTBuffer</primary></indexterm><programlisting>typedef struct _PangoOTBuffer PangoOTBuffer;</programlisting>
<para>
The <link linkend="PangoOTBuffer"><type>PangoOTBuffer</type></link> structure is used to store strings of glyphs associated
with a <link linkend="PangoFcFont"><type>PangoFcFont</type></link>, suitable for OpenType layout processing.  It contains
only private fields and should only be accessed via the
<function>pango_ot_buffer_*</function> functions which are documented below.
To obtain a <link linkend="PangoOTBuffer"><type>PangoOTBuffer</type></link>, use <link linkend="pango-ot-buffer-new"><function>pango_ot_buffer_new()</function></link>.
</para></refsect2>
<refsect2>
<title><anchor id="PangoOTGlyph" role="struct"/>PangoOTGlyph</title>
<indexterm><primary>PangoOTGlyph</primary></indexterm><programlisting>typedef struct {
  guint    glyph;
  guint    properties;
  guint    cluster;
  gushort  component;
  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>
<title><anchor id="PangoOTRuleset" role="struct"/>PangoOTRuleset</title>
<indexterm><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>
<title><anchor id="PangoOTTableType" role="enum"/>enum PangoOTTableType</title>
<indexterm><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>
<term><anchor id="PANGO-OT-TABLE-GSUB:CAPS" role="constant"/><literal>PANGO_OT_TABLE_GSUB</literal></term>
<listitem><simpara>The GSUB table.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><anchor id="PANGO-OT-TABLE-GPOS:CAPS" role="constant"/><literal>PANGO_OT_TABLE_GPOS</literal></term>
<listitem><simpara>The GPOS table.

</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>