glyphs.xml

GTK+-2.0源码之pango-1.15.6.tar.gz

</para>
<para>
For better accuracy, you should use <link linkend="pango-matrix-transform-rectangle"><function>pango_matrix_transform_rectangle()</function></link> on
original rectangle in Pango units and convert to pixels afterward
using <link linkend="pango-extents-to-pixels"><function>pango_extents_to_pixels()</function></link> as <parameter>ink_rect</parameter>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>matrix</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoMatrix"><type>PangoMatrix</type></link>, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>rect</parameter>&nbsp;:</term>
<listitem><simpara> in/out bounding box in device units, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>
</simpara></listitem></varlistentry>
</variablelist><para>Since  1.16
</para></refsect2>
<refsect2>
<title><anchor id="pango-matrix-get-font-scale-factor" role="function" condition="since:1.12"/>pango_matrix_get_font_scale_factor ()</title>
<indexterm role="1.12"><primary>pango_matrix_get_font_scale_factor</primary></indexterm><programlisting><link linkend="double">double</link>      pango_matrix_get_font_scale_factor
                                            (const <link linkend="PangoMatrix">PangoMatrix</link> *matrix);</programlisting>
<para>
Returns the scale factor of a matrix on the height of the font.
That is, the scale factor in the direction perpendicular to the
vector that the X coordinate is mapped to.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>matrix</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoMatrix"><type>PangoMatrix</type></link>, may be <link linkend="NULL:CAPS"><literal>NULL</literal></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the scale factor of <parameter>matrix</parameter> on the height of the font,
or 1.0 if <parameter>matrix</parameter> is <link linkend="NULL:CAPS"><literal>NULL</literal></link>.

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.12
</para></refsect2>
<refsect2>
<title><anchor id="PangoGlyph" role="typedef"/>PangoGlyph</title>
<indexterm><primary>PangoGlyph</primary></indexterm><programlisting>typedef guint32 PangoGlyph;
</programlisting>
<para>
A <link linkend="PangoGlyph"><type>PangoGlyph</type></link> represents a single glyph in the output form of a string.
</para></refsect2>
<refsect2>
<title><anchor id="PANGO-GLYPH-EMPTY:CAPS" role="macro"/>PANGO_GLYPH_EMPTY</title>
<indexterm><primary>PANGO_GLYPH_EMPTY</primary></indexterm><programlisting>#define PANGO_GLYPH_EMPTY           ((PangoGlyph)0x0FFFFFFF)
</programlisting>
<para>
The <link linkend="PANGO-GLYPH-EMPTY:CAPS"><literal>PANGO_GLYPH_EMPTY</literal></link> macro represents a <link linkend="PangoGlyph"><type>PangoGlyph</type></link> value that has a
special meaning, which is a zero-width empty glyph.  This is useful for
example in shaper modules, to use as the glyph for various zero-width
Unicode characters (those passing <link linkend="pango-is-zero-width"><function>pango_is_zero_width()</function></link>).
</para></refsect2>
<refsect2>
<title><anchor id="PANGO-GLYPH-UNKNOWN-FLAG:CAPS" role="macro"/>PANGO_GLYPH_UNKNOWN_FLAG</title>
<indexterm><primary>PANGO_GLYPH_UNKNOWN_FLAG</primary></indexterm><programlisting>#define PANGO_GLYPH_UNKNOWN_FLAG    ((PangoGlyph)0x10000000)
</programlisting>
<para>
The <link linkend="PANGO-GLYPH-UNKNOWN-FLAG:CAPS"><literal>PANGO_GLYPH_UNKNOWN_FLAG</literal></link> macro is a flag value that can be added to
a <link linkend="gunichar"><type>gunichar</type></link> value of a valid Unicode character, to produce a <link linkend="PangoGlyph"><type>PangoGlyph</type></link>
value, representing an unknown-character glyph for the respective <link linkend="gunichar"><type>gunichar</type></link>.
</para></refsect2>
<refsect2>
<title><anchor id="PANGO-GET-UNKNOWN-GLYPH:CAPS" role="macro"/>PANGO_GET_UNKNOWN_GLYPH()</title>
<indexterm><primary>PANGO_GET_UNKNOWN_GLYPH</primary></indexterm><programlisting>#define PANGO_GET_UNKNOWN_GLYPH(wc) ((PangoGlyph)(wc)|PANGO_GLYPH_UNKNOWN_FLAG)
</programlisting>
<para>
Returns a <link linkend="PangoGlyph"><type>PangoGlyph</type></link> value that means no glyph was found for <parameter>wc</parameter>.
The way this unknown glyphs are rendered is backend specific.  For example,
a box with the hexadecimal Unicode code-point of the character written in it
is what is done in the most common backends.
</para><variablelist role="params">
<varlistentry><term><parameter>wc</parameter>&nbsp;:</term>
<listitem><simpara>a Unicode character


</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="PangoGlyphInfo" role="struct"/>PangoGlyphInfo</title>
<indexterm><primary>PangoGlyphInfo</primary></indexterm><programlisting>typedef struct {
  PangoGlyph    glyph;
  PangoGlyphGeometry geometry;
  PangoGlyphVisAttr  attr;
} PangoGlyphInfo;
</programlisting>
<para>
The <link linkend="PangoGlyphInfo"><type>PangoGlyphInfo</type></link> structure represents a single glyph together with
positioning information and visual attributes.
It contains the following fields.
</para><variablelist role="struct">
<varlistentry>
<term><link linkend="PangoGlyph">PangoGlyph</link>&nbsp;<structfield>glyph</structfield>;</term>
<listitem><simpara>the glyph itself.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="PangoGlyphGeometry">PangoGlyphGeometry</link>&nbsp;<structfield>geometry</structfield>;</term>
<listitem><simpara>the positional information about the glyph.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="PangoGlyphVisAttr">PangoGlyphVisAttr</link>&nbsp;<structfield>attr</structfield>;</term>
<listitem><simpara>the visual attributes of the glyph.

</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="PangoGlyphGeometry" role="struct"/>PangoGlyphGeometry</title>
<indexterm><primary>PangoGlyphGeometry</primary></indexterm><programlisting>typedef struct {
  PangoGlyphUnit width;
  PangoGlyphUnit x_offset;
  PangoGlyphUnit y_offset;
} PangoGlyphGeometry;
</programlisting>
<para>
The <link linkend="PangoGlyphGeometry"><type>PangoGlyphGeometry</type></link> structure contains width and positioning
information for a single glyph. 
</para><variablelist role="struct">
<varlistentry>
<term><link linkend="PangoGlyphUnit">PangoGlyphUnit</link>&nbsp;<structfield>width</structfield>;</term>
<listitem><simpara>the logical width to use for the the character.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="PangoGlyphUnit">PangoGlyphUnit</link>&nbsp;<structfield>x_offset</structfield>;</term>
<listitem><simpara>horizontal offset from nominal character position.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="PangoGlyphUnit">PangoGlyphUnit</link>&nbsp;<structfield>y_offset</structfield>;</term>
<listitem><simpara>vertical offset from nominal character position.

</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="PangoGlyphUnit" role="typedef"/>PangoGlyphUnit</title>
<indexterm><primary>PangoGlyphUnit</primary></indexterm><programlisting>typedef gint32 PangoGlyphUnit;
</programlisting>
<para>
The <link linkend="PangoGlyphUnit"><type>PangoGlyphUnit</type></link> type is used to store dimensions within
Pango. Dimensions are stored in 1/<link linkend="PANGO-SCALE:CAPS"><literal>PANGO_SCALE</literal></link> of a device unit.
(A device unit might be a pixel for screen display, or
a point on a printer.) <link linkend="PANGO-SCALE:CAPS"><literal>PANGO_SCALE</literal></link> is currently 1024, and
may change in the future (unlikely though), but you should not
depend on its exact value. The <link linkend="PANGO-PIXELS:CAPS"><function>PANGO_PIXELS()</function></link> macro can be used
to convert from glyph units into device units with correct rounding.
</para></refsect2>
<refsect2>
<title><anchor id="PangoGlyphVisAttr" role="struct"/>PangoGlyphVisAttr</title>
<indexterm><primary>PangoGlyphVisAttr</primary></indexterm><programlisting>typedef struct {
  guint is_cluster_start : 1;
} PangoGlyphVisAttr;
</programlisting>
<para>
The PangoGlyphVisAttr is used to communicate information between
the shaping phase and the rendering phase.  More attributes may be
added in the future.
</para><variablelist role="struct">
<varlistentry>
<term><link linkend="guint">guint</link>&nbsp;<structfield>is_cluster_start</structfield>&nbsp;:&nbsp;1;</term>
<listitem><simpara>set for the first logical glyph in each cluster. (Clusters
		   are stored in visual order, within the cluster, glyphs
		   are always ordered in logical order, since visual
		   order is meaningless; that is, in Arabic text, accent glyphs
		   follow the glyphs for the base character.)

</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="PangoGlyphString" role="struct"/>PangoGlyphString</title>
<indexterm><primary>PangoGlyphString</primary></indexterm><programlisting>typedef struct {
  gint num_glyphs;

  PangoGlyphInfo *glyphs;

  /* This is a memory inefficient way of representing the information
   * here - each value gives the byte index within the text
   * corresponding to the glyph string of the start of the cluster to
   * which the glyph belongs.
   */
  gint *log_clusters;
} PangoGlyphString;
</programlisting>
<para>
The <link linkend="PangoGlyphString"><type>PangoGlyphString</type></link> structure is used to store strings
of glyphs with geometry and visual attribute information.
The storage for the glyph information is owned
by the structure which simplifies memory management.
</para><variablelist role="struct">
<varlistentry>
<term><link linkend="gint">gint</link>&nbsp;<structfield>num_glyphs</structfield>;</term>
<listitem><simpara>the number of glyphs in the string.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="PangoGlyphInfo">PangoGlyphInfo</link>&nbsp;*<structfield>glyphs</structfield>;</term>
<listitem><simpara>an array of <link linkend="PangoGlyphInfo"><type>PangoGlyphInfo</type></link> structures of length <structfield>num_glyphs</structfield>.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="gint">gint</link>&nbsp;*<structfield>log_clusters</structfield>;</term>
<listitem><simpara>for each glyph, byte index of the starting character for the
cluster. The indices are relative to the start of the text
corresponding to the PangoGlyphString.

</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="PangoGlyphItem" role="struct"/>PangoGlyphItem</title>
<indexterm><primary>PangoGlyphItem</primary></indexterm><programlisting>typedef struct {
  PangoItem        *item;
  PangoGlyphString *glyphs;
} PangoGlyphItem;
</programlisting>
<para>
A <link linkend="PangoGlyphItem"><type>PangoGlyphItem</type></link> is a pair of a <link linkend="PangoItem"><type>PangoItem</type></link> and the glyphs
resulting from shaping the text corresponding to an item.
As an example of the usage of <link linkend="PangoGlyphItem"><type>PangoGlyphItem</type></link>, the results
of shaping text with <link linkend="PangoLayout"><type>PangoLayout</type></link> is a list of <link linkend="PangoLayoutLine"><type>PangoLayoutLine</type></link>,
each of which contains a list of <link linkend="PangoGlyphItem"><type>PangoGlyphItem</type></link>.