xft-fonts.xml

GTK+-2.0源码之pango-1.15.6.tar.gz

<refentry id="pango-Xft-Fonts-and-Rendering">
<refmeta>
<refentrytitle id="top_of_page">Xft Fonts and Rendering</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>PANGO Library</refmiscinfo>
</refmeta>

<refnamediv>
<refname>Xft Fonts and Rendering</refname>
<refpurpose>Font handling and rendering with the Xft backend</refpurpose>
<!--[<xref linkend="desc" endterm="desc.title"/>]-->
</refnamediv>

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



            <link linkend="PangoXftFont-struct">PangoXftFont</link>;
            <link linkend="PangoXftFontMap">PangoXftFontMap</link>;
#define     <link linkend="PANGO-RENDER-TYPE-XFT:CAPS">PANGO_RENDER_TYPE_XFT</link>
<link linkend="PangoContext">PangoContext</link>* <link linkend="pango-xft-get-context">pango_xft_get_context</link>         (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen);
<link linkend="PangoFontMap">PangoFontMap</link>* <link linkend="pango-xft-get-font-map">pango_xft_get_font_map</link>        (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen);
<link linkend="void">void</link>        <link linkend="pango-xft-set-default-substitute">pango_xft_set_default_substitute</link>
                                            (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen,
                                             <link linkend="PangoXftSubstituteFunc">PangoXftSubstituteFunc</link> func,
                                             <link linkend="gpointer">gpointer</link> data,
                                             <link linkend="GDestroyNotify">GDestroyNotify</link> notify);
<link linkend="void">void</link>        (<link linkend="PangoXftSubstituteFunc">*PangoXftSubstituteFunc</link>)       (<link linkend="FcPattern">FcPattern</link> *pattern,
                                             <link linkend="gpointer">gpointer</link> data);
<link linkend="void">void</link>        <link linkend="pango-xft-substitute-changed">pango_xft_substitute_changed</link>    (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen);
<link linkend="void">void</link>        <link linkend="pango-xft-shutdown-display">pango_xft_shutdown_display</link>      (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen);
<link linkend="XftFont">XftFont</link>*    <link linkend="pango-xft-font-get-font">pango_xft_font_get_font</link>         (<link linkend="PangoFont">PangoFont</link> *font);
<link linkend="Display">Display</link>*    <link linkend="pango-xft-font-get-display">pango_xft_font_get_display</link>      (<link linkend="PangoFont">PangoFont</link> *font);
<link linkend="gboolean">gboolean</link>    <link linkend="pango-xft-font-has-char">pango_xft_font_has_char</link>         (<link linkend="PangoFont">PangoFont</link> *font,
                                             <link linkend="gunichar">gunichar</link> wc);
<link linkend="FT-Face">FT_Face</link>     <link linkend="pango-xft-font-lock-face">pango_xft_font_lock_face</link>        (<link linkend="PangoFont">PangoFont</link> *font);
<link linkend="void">void</link>        <link linkend="pango-xft-font-unlock-face">pango_xft_font_unlock_face</link>      (<link linkend="PangoFont">PangoFont</link> *font);
<link linkend="guint">guint</link>       <link linkend="pango-xft-font-get-glyph">pango_xft_font_get_glyph</link>        (<link linkend="PangoFont">PangoFont</link> *font,
                                             <link linkend="gunichar">gunichar</link> wc);
<link linkend="PangoGlyph">PangoGlyph</link>  <link linkend="pango-xft-font-get-unknown-glyph">pango_xft_font_get_unknown_glyph</link>
                                            (<link linkend="PangoFont">PangoFont</link> *font,
                                             <link linkend="gunichar">gunichar</link> wc);
            <link linkend="PangoXftRenderer">PangoXftRenderer</link>;
            <link linkend="PangoXftRendererClass">PangoXftRendererClass</link>;
<link linkend="PangoRenderer">PangoRenderer</link>* <link linkend="pango-xft-renderer-new">pango_xft_renderer_new</link>       (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen);
<link linkend="void">void</link>        <link linkend="pango-xft-renderer-set-draw">pango_xft_renderer_set_draw</link>     (<link linkend="PangoXftRenderer">PangoXftRenderer</link> *xftrenderer,
                                             <link linkend="XftDraw">XftDraw</link> *draw);
<link linkend="void">void</link>        <link linkend="pango-xft-renderer-set-default-color">pango_xft_renderer_set_default_color</link>
                                            (<link linkend="PangoXftRenderer">PangoXftRenderer</link> *xftrenderer,
                                             <link linkend="PangoColor">PangoColor</link> *default_color);
<link linkend="void">void</link>        <link linkend="pango-xft-render">pango_xft_render</link>                (<link linkend="XftDraw">XftDraw</link> *draw,
                                             <link linkend="XftColor">XftColor</link> *color,
                                             <link linkend="PangoFont">PangoFont</link> *font,
                                             <link linkend="PangoGlyphString">PangoGlyphString</link> *glyphs,
                                             <link linkend="gint">gint</link> x,
                                             <link linkend="gint">gint</link> y);
<link linkend="void">void</link>        <link linkend="pango-xft-picture-render">pango_xft_picture_render</link>        (<link linkend="Display">Display</link> *display,
                                             <link linkend="Picture">Picture</link> src_picture,
                                             <link linkend="Picture">Picture</link> dest_picture,
                                             <link linkend="PangoFont">PangoFont</link> *font,
                                             <link linkend="PangoGlyphString">PangoGlyphString</link> *glyphs,
                                             <link linkend="gint">gint</link> x,
                                             <link linkend="gint">gint</link> y);
<link linkend="void">void</link>        <link linkend="pango-xft-render-transformed">pango_xft_render_transformed</link>    (<link linkend="XftDraw">XftDraw</link> *draw,
                                             <link linkend="XftColor">XftColor</link> *color,
                                             <link linkend="PangoMatrix">PangoMatrix</link> *matrix,
                                             <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-xft-render-layout-line">pango_xft_render_layout_line</link>    (<link linkend="XftDraw">XftDraw</link> *draw,
                                             <link linkend="XftColor">XftColor</link> *color,
                                             <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-xft-render-layout">pango_xft_render_layout</link>         (<link linkend="XftDraw">XftDraw</link> *draw,
                                             <link linkend="XftColor">XftColor</link> *color,
                                             <link linkend="PangoLayout">PangoLayout</link> *layout,
                                             <link linkend="int">int</link> x,
                                             <link linkend="int">int</link> y);


</synopsis>
</refsynopsisdiv>

<refsect1 id="object_hierarchy">
<title id="object_hierarchy.title">Object Hierarchy</title>
<synopsis>

  <link linkend="GObject">GObject</link>
   +----<link linkend="PangoFont">PangoFont</link>
         +----<link linkend="PangoFcFont">PangoFcFont</link>
               +----PangoXftFont
</synopsis>

</refsect1>








<refsect1 id="desc">
<title id="desc.title">Description</title>
<para>
The Xft library is a library for displaying fonts on the X window
system; internally it uses the fontconfig library to locate font
files, and the FreeType library to load and render fonts. The
Xft backend is the recommended Pango font backend for screen
display with X. (The <link linkend="pango-Cairo-Rendering">Cairo back end</link> is another possibility.)
</para>
<para>
Using the Xft backend is generally straightforward;
<link linkend="pango-xft-get-context"><function>pango_xft_get_context()</function></link> creates a context for a specified display
and screen. You can then create a <link linkend="PangoLayout"><type>PangoLayout</type></link> with that context
and render it with <link linkend="pango-xft-render-layout"><function>pango_xft_render_layout()</function></link>. At a more advanced
level, the low-level fontconfig options used for rendering fonts
can be affected using <link linkend="pango-xft-set-default-substitute"><function>pango_xft_set_default_substitute()</function></link>, and
<link linkend="pango-xft-substitute-changed"><function>pango_xft_substitute_changed()</function></link>.
</para>
<para>
A range of functions for drawing pieces of a layout, such as
individual layout lines and glyphs strings are provided.  You can also
directly create a <link linkend="PangoXftRenderer"><type>PangoXftRenderer</type></link>. Finally, in some advanced cases, it
is useful to derive from <link linkend="PangoXftRenderer"><type>PangoXftRenderer</type></link>. Deriving from
<link linkend="PangoXftRenderer"><type>PangoXftRenderer</type></link> is useful for two reasons. One reason is be to
support custom attributes by overriding <link linkend="PangoRendererClass"><type>PangoRendererClass</type></link> virtual
functions like 'prepare_run' or 'draw_shape'. The reason is to
customize exactly how the final bits are drawn to the destination by
overriding the <link linkend="PangoXftRendererClass"><type>PangoXftRendererClass</type></link> virtual functions
'composite_glyphs' and 'composite_trapezoids'.
</para>
</refsect1>

<refsect1 id="details">
<title id="details.title">Details</title>
<refsect2>
<title><anchor id="PangoXftFont-struct" role="struct"/>PangoXftFont</title>
<indexterm><primary>PangoXftFont</primary></indexterm><programlisting>typedef struct _PangoXftFont PangoXftFont;</programlisting>
<para>
<link linkend="PangoXftFont"><type>PangoXftFont</type></link> is an implementation of <link linkend="PangoFcFont"><type>PangoFcFont</type></link> using the Xft
library for rendering.  It is used in conjunction with <link linkend="PangoXftFontMap"><type>PangoXftFontMap</type></link>.
</para></refsect2>
<refsect2>
<title><anchor id="PangoXftFontMap" role="struct"/>PangoXftFontMap</title>
<indexterm><primary>PangoXftFontMap</primary></indexterm><programlisting>typedef struct _PangoXftFontMap PangoXftFontMap;</programlisting>
<para>
<link linkend="PangoXftFontMap"><type>PangoXftFontMap</type></link> is an implementation of <link linkend="PangoFcFontMap"><type>PangoFcFontMap</type></link> suitable for
the Xft library as the renderer.  It is used in to create fonts of
type <link linkend="PangoXftFont"><type>PangoXftFont</type></link>.
</para></refsect2>
<refsect2>
<title><anchor id="PANGO-RENDER-TYPE-XFT:CAPS" role="macro" condition="deprecated:"/>PANGO_RENDER_TYPE_XFT</title>
<indexterm role="deprecated"><primary>PANGO_RENDER_TYPE_XFT</primary></indexterm><programlisting>#define PANGO_RENDER_TYPE_XFT "PangoRenderXft"
</programlisting>
<warning><para><literal>PANGO_RENDER_TYPE_XFT</literal> is deprecated and should not be used in newly-written code.</para></warning>
<para>
A string constant that was used to identify shape engines that work
with the Xft backend. See <link linkend="PANGO-RENDER-TYPE-FC:CAPS"><literal>PANGO_RENDER_TYPE_FC</literal></link> for the replacement.
</para></refsect2>
<refsect2>
<title><anchor id="pango-xft-get-context" role="function"/>pango_xft_get_context ()</title>
<indexterm><primary>pango_xft_get_context</primary></indexterm><programlisting><link linkend="PangoContext">PangoContext</link>* pango_xft_get_context         (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen);</programlisting>
<para>
Retrieves a <link linkend="PangoContext"><type>PangoContext</type></link> appropriate for rendering with
Xft fonts on the given screen of the given display.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>display</parameter>&nbsp;:</term>
<listitem><simpara> an X display.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>screen</parameter>&nbsp;:</term>
<listitem><simpara> an X screen.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the new <link linkend="PangoContext"><type>PangoContext</type></link>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="pango-xft-get-font-map" role="function" condition="since:1.2"/>pango_xft_get_font_map ()</title>
<indexterm role="1.2"><primary>pango_xft_get_font_map</primary></indexterm><programlisting><link linkend="PangoFontMap">PangoFontMap</link>* pango_xft_get_font_map        (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen);</programlisting>
<para>
Returns the <link linkend="PangoXftFontmap"><type>PangoXftFontmap</type></link> for the given display and screen.
The fontmap is owned by Pango and will be valid until
the display is closed.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>display</parameter>&nbsp;:</term>
<listitem><simpara> an X display
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>screen</parameter>&nbsp;:</term>
<listitem><simpara> the screen number of a screen within <parameter>display</parameter>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> a <link linkend="PangoFontMap"><type>PangoFontMap</type></link> object, owned by Pango.

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="pango-xft-set-default-substitute" role="function" condition="since:1.2"/>pango_xft_set_default_substitute ()</title>
<indexterm role="1.2"><primary>pango_xft_set_default_substitute</primary></indexterm><programlisting><link linkend="void">void</link>        pango_xft_set_default_substitute
                                            (<link linkend="Display">Display</link> *display,
                                             <link linkend="int">int</link> screen,
                                             <link linkend="PangoXftSubstituteFunc">PangoXftSubstituteFunc</link> func,
                                             <link linkend="gpointer">gpointer</link> data,
                                             <link linkend="GDestroyNotify">GDestroyNotify</link> notify);</programlisting>
<para>
Sets a function that will be called to do final configuration
substitution on a <link linkend="FcPattern"><type>FcPattern</type></link> before it is used to load
the font. This function can be used to do things like set
hinting and antialiasing options.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>display</parameter>&nbsp;:</term>
<listitem><simpara> an X Display
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>screen</parameter>&nbsp;:</term>
<listitem><simpara> the screen number of a screen within <parameter>display</parameter>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>func</parameter>&nbsp;:</term>
<listitem><simpara> function to call to to do final config tweaking
       on <link linkend="FcPattern"><type>FcPattern</type></link> objects.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>data</parameter>&nbsp;:</term>
<listitem><simpara> data to pass to <parameter>func</parameter>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>notify</parameter>&nbsp;:</term>
<listitem><simpara> function to call when <parameter>data</parameter> is no longer used.
</simpara></listitem></varlistentry>