pango-renderer.xml

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

<refentry id="PangoRenderer">
<refmeta>
<refentrytitle role="top_of_page" id="PangoRenderer.top_of_page">PangoRenderer</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>PANGO Library</refmiscinfo>
</refmeta>

<refnamediv>
<refname>PangoRenderer</refname>
<refpurpose>Rendering driver base class</refpurpose>
<!--[<xref linkend="desc" endterm="desc.title"/>]-->
</refnamediv>

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

<synopsis>
                    <link linkend="PangoRenderer-struct">PangoRenderer</link>;
enum                <link linkend="PangoRenderPart">PangoRenderPart</link>;
#define             <link linkend="PANGO-TYPE-RENDER-PART:CAPS">PANGO_TYPE_RENDER_PART</link>
                    <link linkend="PangoRendererClass">PangoRendererClass</link>;
<link linkend="void">void</link>                <link linkend="pango-renderer-draw-layout">pango_renderer_draw_layout</link>          (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoLayout">PangoLayout</link> *layout,
                                                         <link linkend="int">int</link> x,
                                                         <link linkend="int">int</link> y);
<link linkend="void">void</link>                <link linkend="pango-renderer-draw-layout-line">pango_renderer_draw_layout_line</link>     (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoLayoutLine">PangoLayoutLine</link> *line,
                                                         <link linkend="int">int</link> x,
                                                         <link linkend="int">int</link> y);
<link linkend="void">void</link>                <link linkend="pango-renderer-draw-glyphs">pango_renderer_draw_glyphs</link>          (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoFont">PangoFont</link> *font,
                                                         <link linkend="PangoGlyphString">PangoGlyphString</link> *glyphs,
                                                         <link linkend="int">int</link> x,
                                                         <link linkend="int">int</link> y);
<link linkend="void">void</link>                <link linkend="pango-renderer-draw-rectangle">pango_renderer_draw_rectangle</link>       (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoRenderPart">PangoRenderPart</link> part,
                                                         <link linkend="int">int</link> x,
                                                         <link linkend="int">int</link> y,
                                                         <link linkend="int">int</link> width,
                                                         <link linkend="int">int</link> height);
<link linkend="void">void</link>                <link linkend="pango-renderer-draw-error-underline">pango_renderer_draw_error_underline</link> (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="int">int</link> x,
                                                         <link linkend="int">int</link> y,
                                                         <link linkend="int">int</link> width,
                                                         <link linkend="int">int</link> height);
<link linkend="void">void</link>                <link linkend="pango-renderer-draw-trapezoid">pango_renderer_draw_trapezoid</link>       (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoRenderPart">PangoRenderPart</link> part,
                                                         <link linkend="double">double</link> y1_,
                                                         <link linkend="double">double</link> x11,
                                                         <link linkend="double">double</link> x21,
                                                         <link linkend="double">double</link> y2,
                                                         <link linkend="double">double</link> x12,
                                                         <link linkend="double">double</link> x22);
<link linkend="void">void</link>                <link linkend="pango-renderer-draw-glyph">pango_renderer_draw_glyph</link>           (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoFont">PangoFont</link> *font,
                                                         <link linkend="PangoGlyph">PangoGlyph</link> glyph,
                                                         <link linkend="double">double</link> x,
                                                         <link linkend="double">double</link> y);
<link linkend="void">void</link>                <link linkend="pango-renderer-activate">pango_renderer_activate</link>             (<link linkend="PangoRenderer">PangoRenderer</link> *renderer);
<link linkend="void">void</link>                <link linkend="pango-renderer-deactivate">pango_renderer_deactivate</link>           (<link linkend="PangoRenderer">PangoRenderer</link> *renderer);
<link linkend="void">void</link>                <link linkend="pango-renderer-part-changed">pango_renderer_part_changed</link>         (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoRenderPart">PangoRenderPart</link> part);
<link linkend="void">void</link>                <link linkend="pango-renderer-set-color">pango_renderer_set_color</link>            (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoRenderPart">PangoRenderPart</link> part,
                                                         const <link linkend="PangoColor">PangoColor</link> *color);
<link linkend="PangoColor">PangoColor</link>*         <link linkend="pango-renderer-get-color">pango_renderer_get_color</link>            (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         <link linkend="PangoRenderPart">PangoRenderPart</link> part);
<link linkend="void">void</link>                <link linkend="pango-renderer-set-matrix">pango_renderer_set_matrix</link>           (<link linkend="PangoRenderer">PangoRenderer</link> *renderer,
                                                         const <link linkend="PangoMatrix">PangoMatrix</link> *matrix);
const <link linkend="PangoMatrix">PangoMatrix</link>*  <link linkend="pango-renderer-get-matrix">pango_renderer_get_matrix</link>           (<link linkend="PangoRenderer">PangoRenderer</link> *renderer);
<link linkend="PangoLayout">PangoLayout</link>*        <link linkend="pango-renderer-get-layout">pango_renderer_get_layout</link>           (<link linkend="PangoRenderer">PangoRenderer</link> *renderer);
<link linkend="PangoLayoutLine">PangoLayoutLine</link>*    <link linkend="pango-renderer-get-layout-line">pango_renderer_get_layout_line</link>      (<link linkend="PangoRenderer">PangoRenderer</link> *renderer);
</synopsis>
</refsynopsisdiv>

<refsect1 id="PangoRenderer.object-hierarchy" role="object_hierarchy">
<title role="object_hierarchy.title">Object Hierarchy</title>
<synopsis>
  <link linkend="GObject">GObject</link>
   +----PangoRenderer
         +----<link linkend="PangoXftRenderer">PangoXftRenderer</link>
</synopsis>

</refsect1>








<refsect1 id="PangoRenderer.description" role="desc">
<title role="desc.title">Description</title>
<para>
<link linkend="PangoRenderer"><type>PangoRenderer</type></link> is a base class that contains the necessary logic for
rendering a <link linkend="PangoLayout"><type>PangoLayout</type></link> or <link linkend="PangoLayoutLine"><type>PangoLayoutLine</type></link>. By subclassing
<link linkend="PangoRenderer"><type>PangoRenderer</type></link> and overriding operations such as <parameter>draw_glyphs</parameter> and
<parameter>draw_rectangle</parameter>, renderers for particular font backends and
destinations can be created.
</para>
</refsect1>

<refsect1 id="PangoRenderer.details" role="details">
<title role="details.title">Details</title>
<refsect2 id="PangoRenderer-struct" role="struct">
<title>PangoRenderer</title>
<indexterm zone="PangoRenderer-struct" role="1.8"><primary>PangoRenderer</primary></indexterm><programlisting>typedef struct {
  PangoMatrix *matrix;		/* May be NULL */
} PangoRenderer;
</programlisting>
<para>
<link linkend="PangoRenderer"><type>PangoRenderer</type></link> is a base class for objects that are used to
render Pango objects such as <link linkend="PangoGlyphString"><type>PangoGlyphString</type></link> and
<link linkend="PangoLayout"><type>PangoLayout</type></link>.</para>
<para>

</para><variablelist role="struct">
<varlistentry>
<term><link linkend="PangoMatrix">PangoMatrix</link>&nbsp;*<structfield>matrix</structfield>;</term>
<listitem><simpara> the current transformation matrix for the Renderer; may
   be <link linkend="NULL:CAPS"><literal>NULL</literal></link>, which should be treated the same as the identity matrix.
</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since  1.8
</para></refsect2>
<refsect2 id="PangoRenderPart" role="enum" condition="since:1.8">
<title>enum PangoRenderPart</title>
<indexterm zone="PangoRenderPart" role="1.8"><primary>PangoRenderPart</primary></indexterm><programlisting>typedef enum
{
  PANGO_RENDER_PART_FOREGROUND,
  PANGO_RENDER_PART_BACKGROUND,
  PANGO_RENDER_PART_UNDERLINE,
  PANGO_RENDER_PART_STRIKETHROUGH
} PangoRenderPart;
</programlisting>
<para>
<link linkend="PangoRenderPart"><type>PangoRenderPart</type></link> defines different items to render for such
purposes as setting colors.</para>
<para>

</para><variablelist role="enum">
<varlistentry id="PANGO-RENDER-PART-FOREGROUND:CAPS" role="constant">
<term><literal>PANGO_RENDER_PART_FOREGROUND</literal></term>
<listitem><simpara> the text itself
</simpara></listitem>
</varlistentry>
<varlistentry id="PANGO-RENDER-PART-BACKGROUND:CAPS" role="constant">
<term><literal>PANGO_RENDER_PART_BACKGROUND</literal></term>
<listitem><simpara> the area behind the text
</simpara></listitem>
</varlistentry>
<varlistentry id="PANGO-RENDER-PART-UNDERLINE:CAPS" role="constant">
<term><literal>PANGO_RENDER_PART_UNDERLINE</literal></term>
<listitem><simpara> underlines
</simpara></listitem>
</varlistentry>
<varlistentry id="PANGO-RENDER-PART-STRIKETHROUGH:CAPS" role="constant">
<term><literal>PANGO_RENDER_PART_STRIKETHROUGH</literal></term>
<listitem><simpara> strikethrough lines
</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since  1.8
</para></refsect2>
<refsect2 id="PANGO-TYPE-RENDER-PART:CAPS" role="macro">
<title>PANGO_TYPE_RENDER_PART</title>
<indexterm zone="PANGO-TYPE-RENDER-PART:CAPS"><primary>PANGO_TYPE_RENDER_PART</primary></indexterm><programlisting>#define PANGO_TYPE_RENDER_PART (pango_render_part_get_type())
</programlisting>
<para>
The <link linkend="GObject"><type>GObject</type></link> type for <link linkend="PangoRenderPart"><type>PangoRenderPart</type></link>.
</para></refsect2>
<refsect2 id="PangoRendererClass" role="struct" condition="since:1.8">
<title>PangoRendererClass</title>
<indexterm zone="PangoRendererClass" role="1.8"><primary>PangoRendererClass</primary></indexterm><programlisting>typedef struct {
  /* All of the following have default implementations
   * and take as coordinates user coordinates in Pango units
   */
  void (*draw_glyphs) (PangoRenderer     *renderer,
		       PangoFont         *font,
		       PangoGlyphString  *glyphs,
		       int                x,
		       int                y);
  void (*draw_rectangle) (PangoRenderer     *renderer,
			  PangoRenderPart    part,
			  int                x,
			  int                y,
			  int                width,
			  int                height);
  void (*draw_error_underline) (PangoRenderer     *renderer,
				int                x,
				int                y,
				int                width,
				int                height);

  /* Nothing is drawn for shaped glyphs unless this is implemented */
  void (*draw_shape) (PangoRenderer  *renderer,
		      PangoAttrShape *attr,
		      int             x,
		      int             y);

  /* These two must be implemented and take coordinates in
   * device space as doubles.
   */
  void (*draw_trapezoid) (PangoRenderer  *renderer,
			  PangoRenderPart part,
			  double          y1_,
			  double          x11,
			  double          x21,
			  double          y2,
			  double          x12,
			  double          x22);
  void (*draw_glyph) (PangoRenderer *renderer,
		      PangoFont     *font,
		      PangoGlyph     glyph,
		      double         x,
		      double         y);

  /* Notification of change in rendering attributes
   */
  void (*part_changed) (PangoRenderer   *renderer,
			PangoRenderPart  part);

  /* Paired around drawing operations
   */
  void (*begin) (PangoRenderer *renderer);
  void (*end)   (PangoRenderer *renderer);

  /* Hooks into the details of layout rendering
   */
  void (*prepare_run) (PangoRenderer  *renderer,
		       PangoLayoutRun *run);
} PangoRendererClass;
</programlisting>
<para>
Class structure for <link linkend="PangoRenderer"><type>PangoRenderer</type></link>.</para>
<para>

</para><variablelist role="struct">
<varlistentry>
<term><structfield>draw_glyphs</structfield>&nbsp;()</term>
<listitem><simpara> draws a <link linkend="PangoGlyphString"><type>PangoGlyphString</type></link>
</simpara></listitem>