opentype.sgml

GTK+-2.0源码之pango-1.15.6.tar.gz

<!-- ##### SECTION Title ##### -->
OpenType Font Handling

<!-- ##### SECTION Short_Description ##### -->
Obtaining information from OpenType tables

<!-- ##### SECTION Long_Description ##### -->
<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>

<!-- ##### SECTION See_Also ##### -->
<para>

</para>

<!-- ##### SECTION Stability_Level ##### -->


<!-- ##### TYPEDEF PangoOTTag ##### -->
<para>
The <type>PangoOTTag</type> typedef is used to represent TrueType and OpenType
four letter tags inside Pango. Use the <function>FT_MAKE_TAG()</function> macro
defined in the FreeType2 header <filename>freetype/freetype.h</filename> to 
create <type>PangoOTTag</type>s manually.
</para>


<!-- ##### STRUCT PangoOTInfo ##### -->
<para>
The #PangoOTInfo 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 #PangoOTInfo,
use pango_ot_info_new().
</para>


<!-- ##### STRUCT PangoOTBuffer ##### -->
<para>
The #PangoOTBuffer structure is used to store strings of glyphs associated
with a #PangoFcFont, 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 #PangoOTBuffer, use pango_ot_buffer_new().
</para>


<!-- ##### STRUCT PangoOTGlyph ##### -->
<para>
The #PangoOTGlyph structure represents a single glyph together with
information used for OpenType layout processing of the glyph.
It contains the following fields.
</para>

@glyph: the glyph itself.
@properties: the properties value, identifying which features should be
	     applied on this glyph.  See pango_ruleset_add_feature().
@cluster: the cluster that this glyph belongs to.
@component: a component value, set by the OpenType layout engine.
@ligID: a ligature index value, set by the OpenType layout engine.
@property_cache: for internal use.

<!-- ##### STRUCT PangoOTRuleset ##### -->
<para>
The #PangoOTRuleSet 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 #PangoOTRuleSet
is created with pango_ot_ruleset_new(), features are added
to it with pango_ot_ruleset_add_feature(), then it is
applied to a #PangoGlyphString with pango_ot_ruleset_shape().
</para>


<!-- ##### ENUM PangoOTTableType ##### -->
<para>
The <type>PangoOTTableType</type> enumeration values are used to
identify the various OpenType tables in the
<function>pango_ot_info_*</function> functions.
</para>

@PANGO_OT_TABLE_GSUB: The GSUB table.
@PANGO_OT_TABLE_GPOS: The GPOS table.

<!-- ##### MACRO PANGO_OT_ALL_GLYPHS ##### -->
<para>
This is used as the property bit in pango_ot_ruleset_add_feature() when a
feature should be applied to all glyphs.
</para>



<!-- ##### MACRO PANGO_OT_DEFAULT_LANGUAGE ##### -->
<para>
This is used as the language index in pango_ot_info_find_feature() when a
the default language system of the script is desired.
</para>



<!-- ##### FUNCTION pango_ot_info_get ##### -->
<para>

</para>

@face: 
@Returns: 


<!-- ##### FUNCTION pango_ot_info_find_script ##### -->
<para>

</para>

@info: 
@table_type: 
@script_tag: 
@script_index: 
@Returns: 


<!-- ##### FUNCTION pango_ot_info_find_language ##### -->
<para>

</para>

@info: 
@table_type: 
@script_index: 
@language_tag: 
@language_index: 
@required_feature_index: 
@Returns: 


<!-- ##### FUNCTION pango_ot_info_find_feature ##### -->
<para>

</para>

@info: 
@table_type: 
@feature_tag: 
@script_index: 
@language_index: 
@feature_index: 
@Returns: 


<!-- ##### FUNCTION pango_ot_info_list_scripts ##### -->
<para>

</para>

@info: 
@table_type: 
@Returns: 


<!-- ##### FUNCTION pango_ot_info_list_languages ##### -->
<para>

</para>

@info: 
@table_type: 
@script_index: 
@language_tag: 
@Returns: 


<!-- ##### FUNCTION pango_ot_info_list_features ##### -->
<para>

</para>

@info: 
@table_type: 
@tag: 
@script_index: 
@language_index: 
@Returns: 


<!-- ##### FUNCTION pango_ot_buffer_new ##### -->
<para>

</para>

@font: 
@Returns: 


<!-- ##### FUNCTION pango_ot_buffer_destroy ##### -->
<para>

</para>

@buffer: 


<!-- ##### FUNCTION pango_ot_buffer_clear ##### -->
<para>

</para>

@buffer: 


<!-- ##### FUNCTION pango_ot_buffer_add_glyph ##### -->
<para>

</para>

@buffer: 
@glyph: 
@properties: 
@cluster: 


<!-- ##### FUNCTION pango_ot_buffer_set_rtl ##### -->
<para>

</para>

@buffer: 
@rtl: 


<!-- ##### FUNCTION pango_ot_buffer_set_zero_width_marks ##### -->
<para>

</para>

@buffer: 
@zero_width_marks: 


<!-- ##### FUNCTION pango_ot_buffer_get_glyphs ##### -->
<para>

</para>

@buffer: 
@glyphs: 
@n_glyphs: 


<!-- ##### FUNCTION pango_ot_buffer_output ##### -->
<para>

</para>

@buffer: 
@glyphs: 


<!-- ##### FUNCTION pango_ot_ruleset_new ##### -->
<para>

</para>

@info: 
@Returns: 


<!-- ##### FUNCTION pango_ot_ruleset_add_feature ##### -->
<para>

</para>

@ruleset: 
@table_type: 
@feature_index: 
@property_bit: 


<!-- ##### FUNCTION pango_ot_ruleset_substitute ##### -->
<para>

</para>

@ruleset: 
@buffer: 


<!-- ##### FUNCTION pango_ot_ruleset_position ##### -->
<para>

</para>

@ruleset: 
@buffer: