glyphs.xml

linux

<para>
This function is useful for example when you want to draw a rotated
<parameter>PangoLayout</parameter> to an image buffer, and want to know how large the image
should be and how much you should shift the layout when rendering.
</para>
<para>
If you have a rectangle in device units (pixels), use
<link linkend="pango-matrix-transform-pixel-rectangle"><function>pango_matrix_transform_pixel_rectangle()</function></link>.
</para>
<para>
If you have the rectangle in Pango units and want to convert to
transformed pixel bounding box, it is more accurate to transform it first
(using this function) and pass the result to <link linkend="pango-extents-to-pixels"><function>pango_extents_to_pixels()</function></link>,
as <parameter>ink_rect</parameter>.  However, there is a reason that you may want to convert
to pixels first and then transform, and that is when the transformed
coordinates may overflow in Pango units (large matrix translation for
example).</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 Pango units, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since  1.16
</para></refsect2>
<refsect2>
<title><anchor id="pango-matrix-transform-pixel-rectangle" role="function" condition="since:1.16"/>pango_matrix_transform_pixel_rectangle ()</title>
<indexterm role="1.16"><primary>pango_matrix_transform_pixel_rectangle</primary></indexterm><programlisting><link linkend="void">void</link>                pango_matrix_transform_pixel_rectangle
                                                        (const <link linkend="PangoMatrix">PangoMatrix</link> *matrix,
                                                         <link linkend="PangoRectangle">PangoRectangle</link> *rect);</programlisting>
<para>
First transforms the <parameter>rect</parameter> using <parameter>matrix</parameter>, then calculates the bounding box
of the transformed rectangle.  The rectangle should be in device units
(pixels).
</para>
<para>
This function is useful for example when you want to draw a rotated
<parameter>PangoLayout</parameter> to an image buffer, and want to know how large the image
should be and how much you should shift the layout when rendering.
</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 role="since">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 role="since">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;