pangocairo.xml

GTK+-2.0源码之pango-1.15.6.tar.gz

  <title>Output of <xref linkend="rotated-example"/></title>
  <graphic fileref="rotated-text.png" format="PNG"/>
</figure>
</refsect1>

<refsect1 id="details">
<title id="details.title">Details</title>
<refsect2>
<title><anchor id="PangoCairoFontMap-struct" role="struct"/>PangoCairoFontMap</title>
<indexterm role="1.10"><primary>PangoCairoFontMap</primary></indexterm><programlisting>typedef struct _PangoCairoFontMap PangoCairoFontMap;</programlisting>
<para>
<link linkend="PangoCairoFontMap"><type>PangoCairoFontMap</type></link> is an interface exported by font maps for
use with Cairo. The actual type of the font map will depend
on the particular font technology Cairo was compiled to use.</para>
<para>

</para><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-font-map-new" role="function" condition="since:1.10"/>pango_cairo_font_map_new ()</title>
<indexterm role="1.10"><primary>pango_cairo_font_map_new</primary></indexterm><programlisting><link linkend="PangoFontMap">PangoFontMap</link>* pango_cairo_font_map_new      (void);</programlisting>
<para>
Creates a new <link linkend="PangoCairoFontMap"><type>PangoCairoFontMap</type></link> object; a fontmap is used
to cache information about available fonts, and holds
certain global parameters such as the resolution.
In most cases, you can use <link linkend="pango-cairo-font-map-get-default"><function>pango_cairo_font_map_get_default()</function></link>
instead.
</para>
<para>
Note that the type of the returned object will depend
on the particular font backend Cairo was compiled to use;
You generally should only use the <link linkend="PangoFontMap"><type>PangoFontMap</type></link> and
<link linkend="PangoCairoFontMap"><type>PangoCairoFontMap</type></link> interfaces on the returned object.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the newly allocated <link linkend="PangoFontMap"><type>PangoFontMap</type></link>, which should
              be freed with <link linkend="g-object-unref"><function>g_object_unref()</function></link>.

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-font-map-get-default" role="function" condition="since:1.10"/>pango_cairo_font_map_get_default ()</title>
<indexterm role="1.10"><primary>pango_cairo_font_map_get_default</primary></indexterm><programlisting><link linkend="PangoFontMap">PangoFontMap</link>* pango_cairo_font_map_get_default
                                            (void);</programlisting>
<para>
Gets a default font map to use with Cairo.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the default Cairo fontmap for <link linkend="Pango"><type>Pango</type></link>. This
 object is owned by Pango and must not be freed.

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-font-map-set-resolution" role="function" condition="since:1.10"/>pango_cairo_font_map_set_resolution ()</title>
<indexterm role="1.10"><primary>pango_cairo_font_map_set_resolution</primary></indexterm><programlisting><link linkend="void">void</link>        pango_cairo_font_map_set_resolution
                                            (<link linkend="PangoCairoFontMap">PangoCairoFontMap</link> *fontmap,
                                             <link linkend="double">double</link> dpi);</programlisting>
<para>
Sets the resolution for the fontmap. This is a scale factor between
points specified in a <link linkend="PangoFontDescription"><type>PangoFontDescription</type></link> and Cairo units. The
default value is 96, meaning that a 10 point font will be 13
units high. (10 * 96. / 72. = 13.3).</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>fontmap</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoCairoFontMap"><type>PangoCairoFontMap</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>dpi</parameter>&nbsp;:</term>
<listitem><simpara> the resolution in "dots per inch". (Physical inches aren't actually
  involved; the terminology is conventional.)
</simpara></listitem></varlistentry>
</variablelist><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-font-map-get-resolution" role="function" condition="since:1.10"/>pango_cairo_font_map_get_resolution ()</title>
<indexterm role="1.10"><primary>pango_cairo_font_map_get_resolution</primary></indexterm><programlisting><link linkend="double">double</link>      pango_cairo_font_map_get_resolution
                                            (<link linkend="PangoCairoFontMap">PangoCairoFontMap</link> *fontmap);</programlisting>
<para>
Gets the resolution for the fontmap. See <link linkend="pango-cairo-font-map-set-resolution"><function>pango_cairo_font_map_set_resolution()</function></link></para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>fontmap</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoCairoFontMap"><type>PangoCairoFontMap</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the resolution in "dots per inch"

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-font-map-create-context" role="function" condition="since:1.10"/>pango_cairo_font_map_create_context ()</title>
<indexterm role="1.10"><primary>pango_cairo_font_map_create_context</primary></indexterm><programlisting><link linkend="PangoContext">PangoContext</link>* pango_cairo_font_map_create_context
                                            (<link linkend="PangoCairoFontMap">PangoCairoFontMap</link> *fontmap);</programlisting>
<para>
Create a <link linkend="PangoContext"><type>PangoContext</type></link> for the given fontmap.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>fontmap</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoCairoFontMap"><type>PangoCairoFontMap</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the newly created context; free with <link linkend="g-object-unref"><function>g_object_unref()</function></link>.

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-context-set-resolution" role="function" condition="since:1.10"/>pango_cairo_context_set_resolution ()</title>
<indexterm role="1.10"><primary>pango_cairo_context_set_resolution</primary></indexterm><programlisting><link linkend="void">void</link>        pango_cairo_context_set_resolution
                                            (<link linkend="PangoContext">PangoContext</link> *context,
                                             <link linkend="double">double</link> dpi);</programlisting>
<para>
Sets the resolution for the context. This is a scale factor between
points specified in a <link linkend="PangoFontDescription"><type>PangoFontDescription</type></link> and Cairo units. The
default value is 96, meaning that a 10 point font will be 13
units high. (10 * 96. / 72. = 13.3).</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>context</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoContext"><type>PangoContext</type></link>, from <link linkend="pango-cairo-font-map-create-context"><function>pango_cairo_font_map_create_context()</function></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>dpi</parameter>&nbsp;:</term>
<listitem><simpara> the resolution in "dots per inch". (Physical inches aren't actually
  involved; the terminology is conventional.) A 0 or negative value
  means to use the resolution from the font map.
</simpara></listitem></varlistentry>
</variablelist><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-context-get-resolution" role="function" condition="since:1.10"/>pango_cairo_context_get_resolution ()</title>
<indexterm role="1.10"><primary>pango_cairo_context_get_resolution</primary></indexterm><programlisting><link linkend="double">double</link>      pango_cairo_context_get_resolution
                                            (<link linkend="PangoContext">PangoContext</link> *context);</programlisting>
<para>
Gets the resolution for the context. See <link linkend="pango-cairo-context-set-resolution"><function>pango_cairo_context_set_resolution()</function></link></para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>context</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoContext"><type>PangoContext</type></link>, from <link linkend="pango-cairo-font-map-create-context"><function>pango_cairo_font_map_create_context()</function></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the resolution in "dots per inch". A negative value will
 be returned if no resolution has previously been set.

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-context-set-font-options" role="function"/>pango_cairo_context_set_font_options ()</title>
<indexterm><primary>pango_cairo_context_set_font_options</primary></indexterm><programlisting><link linkend="void">void</link>        pango_cairo_context_set_font_options
                                            (<link linkend="PangoContext">PangoContext</link> *context,
                                             const <link linkend="cairo-font-options-t">cairo_font_options_t</link> *options);</programlisting>
<para>
Sets the font options used when rendering text with this context.
These options override any options that <link linkend="pango-cairo-update-context"><function>pango_cairo_update_context()</function></link>
derives from the target surface.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>context</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoContext"><type>PangoContext</type></link>, from <link linkend="pango-cairo-font-map-create-context"><function>pango_cairo_font_map_create_context()</function></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>options</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link>, or <link linkend="NULL:CAPS"><literal>NULL</literal></link> to unset any previously set
          options. A copy is made.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="pango-cairo-context-get-font-options" role="function"/>pango_cairo_context_get_font_options ()</title>
<indexterm><primary>pango_cairo_context_get_font_options</primary></indexterm><programlisting>const <link linkend="cairo-font-options-t">cairo_font_options_t</link>* pango_cairo_context_get_font_options
                                            (<link linkend="PangoContext">PangoContext</link> *context);</programlisting>
<para>
Retrieves any font rendering options previously set with
<link linkend="pango-cairo-font-map-set-font-options"><function>pango_cairo_font_map_set_font_options()</function></link>. This functions not report options
that are derived from the target surface by <link linkend="pango-cairo-update-context"><function>pango_cairo_update_context()</function></link></para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>context</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoContext"><type>PangoContext</type></link>, from <link linkend="pango-cairo-font-map-create-context"><function>pango_cairo_font_map_create_context()</function></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the font options previously set on the context, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>
  if no options have been set. This value is owned by the context
  and must not be modified or freed.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="pango-cairo-update-context" role="function" condition="since:1.10"/>pango_cairo_update_context ()</title>
<indexterm role="1.10"><primary>pango_cairo_update_context</primary></indexterm><programlisting><link linkend="void">void</link>        pango_cairo_update_context      (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="PangoContext">PangoContext</link> *context);</programlisting>
<para>
Updates a <link linkend="PangoContext"><type>PangoContext</type></link> previously created for use with Cairo to
match the current transformation and target surface of a Cairo
context. If any layouts have been created for the context,
it's necessary to call <link linkend="pango-layout-context-changed"><function>pango_layout_context_changed()</function></link> on those
layouts.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a Cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>context</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="PangoContext"><type>PangoContext</type></link>, from <link linkend="pango-cairo-font-map-create-context"><function>pango_cairo_font_map_create_context()</function></link>
</simpara></listitem></varlistentry>
</variablelist><para>Since  1.10
</para></refsect2>
<refsect2>
<title><anchor id="pango-cairo-create-layout" role="function" condition="since:1.10"/>pango_cairo_create_layout ()</title>
<indexterm role="1.10"><primary>pango_cairo_create_layout</primary></indexterm><programlisting><link linkend="PangoLayout">PangoLayout</link>* pango_cairo_create_layout      (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Creates a layout object set up to match the current transformation
and target surface of the Cairo context.  This layout can then be
used for text measurement with functions like
<link linkend="pango-layout-get-size"><function>pango_layout_get_size()</function></link> or drawing with functions like
<link linkend="pango-cairo-show-layout"><function>pango_cairo_show_layout()</function></link>. If you change the transformation
or target surface for <parameter>cr</parameter>, you need to call <link linkend="pango-cairo-update-layout"><function>pango_cairo_update_layout()</function></link>
</para>
<para>
This function is the most convenient way to use Cairo with Pango,
however it is slightly inefficient since it creates a separate
<link linkend="PangoContext"><type>PangoContext</type></link> object for each layout. This might matter in an
application that was laying out large amounts of text.</para>