path: root/libs/cairo-1.16.0/doc/public/xml/cairo-surface.xml

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<refentry id="cairo-cairo-surface-t">
<refmeta>
<refentrytitle role="top_of_page" id="cairo-cairo-surface-t.top_of_page">cairo_surface_t</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>CAIRO Library</refmiscinfo>
</refmeta>
<refnamediv>
<refname>cairo_surface_t</refname>
<refpurpose>Base class for surfaces</refpurpose>
</refnamediv>

<refsect1 id="cairo-cairo-surface-t.functions" role="functions_proto">
<title role="functions_proto.title">Functions</title>
<informaltable pgwide="1" frame="none">
<tgroup cols="2">
<colspec colname="functions_return" colwidth="150px"/>
<colspec colname="functions_name"/>
<tbody>
<row><entry role="function_type"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
</entry><entry role="function_name"><link linkend="cairo-surface-create-similar">cairo_surface_create_similar</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
</entry><entry role="function_name"><link linkend="cairo-surface-create-similar-image">cairo_surface_create_similar_image</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
</entry><entry role="function_name"><link linkend="cairo-surface-create-for-rectangle">cairo_surface_create_for_rectangle</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
</entry><entry role="function_name"><link linkend="cairo-surface-reference">cairo_surface_reference</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-destroy">cairo_surface_destroy</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-status">cairo_surface_status</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-finish">cairo_surface_finish</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-flush">cairo_surface_flush</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-device-t"><returnvalue>cairo_device_t</returnvalue></link>&#160;*
</entry><entry role="function_name"><link linkend="cairo-surface-get-device">cairo_surface_get_device</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-get-font-options">cairo_surface_get_font_options</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-content-t"><returnvalue>cairo_content_t</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-get-content">cairo_surface_get_content</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-mark-dirty">cairo_surface_mark_dirty</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-mark-dirty-rectangle">cairo_surface_mark_dirty_rectangle</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-set-device-offset">cairo_surface_set_device_offset</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-get-device-offset">cairo_surface_get_device_offset</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-get-device-scale">cairo_surface_get_device_scale</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-set-device-scale">cairo_surface_set_device_scale</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-set-fallback-resolution">cairo_surface_set_fallback_resolution</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-get-fallback-resolution">cairo_surface_get_fallback_resolution</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-surface-type-t"><returnvalue>cairo_surface_type_t</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-get-type">cairo_surface_get_type</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type">unsigned <link linkend="int"><returnvalue>int</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-get-reference-count">cairo_surface_get_reference_count</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-set-user-data">cairo_surface_set_user_data</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>&#160;*
</entry><entry role="function_name"><link linkend="cairo-surface-get-user-data">cairo_surface_get_user_data</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-copy-page">cairo_surface_copy_page</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-show-page">cairo_surface_show_page</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-bool-t"><returnvalue>cairo_bool_t</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-has-show-text-glyphs">cairo_surface_has_show_text_glyphs</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-set-mime-data">cairo_surface_set_mime_data</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-get-mime-data">cairo_surface_get_mime_data</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-bool-t"><returnvalue>cairo_bool_t</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-supports-mime-type">cairo_surface_supports_mime_type</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
</entry><entry role="function_name"><link linkend="cairo-surface-map-to-image">cairo_surface_map_to_image</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>
<row><entry role="function_type"><link linkend="void"><returnvalue>void</returnvalue></link>
</entry><entry role="function_name"><link linkend="cairo-surface-unmap-image">cairo_surface_unmap_image</link>&#160;<phrase role="c_punctuation">()</phrase></entry></row>

</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 id="cairo-cairo-surface-t.other" role="other_proto">
<title role="other_proto.title">Types and Values</title>
<informaltable role="enum_members_table" pgwide="1" frame="none">
<tgroup cols="2">
<colspec colname="name" colwidth="150px"/>
<colspec colname="description"/>
<tbody>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-HAS-MIME-SURFACE:CAPS">CAIRO_HAS_MIME_SURFACE</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-CCITT-FAX:CAPS">CAIRO_MIME_TYPE_CCITT_FAX</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-CCITT-FAX-PARAMS:CAPS">CAIRO_MIME_TYPE_CCITT_FAX_PARAMS</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-EPS:CAPS">CAIRO_MIME_TYPE_EPS</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-EPS-PARAMS:CAPS">CAIRO_MIME_TYPE_EPS_PARAMS</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-JBIG2:CAPS">CAIRO_MIME_TYPE_JBIG2</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-JBIG2-GLOBAL:CAPS">CAIRO_MIME_TYPE_JBIG2_GLOBAL</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-JBIG2-GLOBAL-ID:CAPS">CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-JP2:CAPS">CAIRO_MIME_TYPE_JP2</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-JPEG:CAPS">CAIRO_MIME_TYPE_JPEG</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-PNG:CAPS">CAIRO_MIME_TYPE_PNG</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-URI:CAPS">CAIRO_MIME_TYPE_URI</link></entry></row>
<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-MIME-TYPE-UNIQUE-ID:CAPS">CAIRO_MIME_TYPE_UNIQUE_ID</link></entry></row>
<row><entry role="typedef_keyword">typedef</entry><entry role="function_name"><link linkend="cairo-surface-t">cairo_surface_t</link></entry></row>
<row><entry role="datatype_keyword">enum</entry><entry role="function_name"><link linkend="cairo-content-t">cairo_content_t</link></entry></row>
<row><entry role="datatype_keyword">enum</entry><entry role="function_name"><link linkend="cairo-surface-type-t">cairo_surface_type_t</link></entry></row>

</tbody>
</tgroup>
</informaltable>
</refsect1>


<refsect1 id="cairo-cairo-surface-t.description" role="desc">
<title role="desc.title">Description</title>
<para><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> is the abstract type representing all different drawing
targets that cairo can render to.  The actual drawings are
performed using a cairo <firstterm>context</firstterm>.</para>
<para>A cairo surface is created by using <firstterm>backend</firstterm>-specific
constructors, typically of the form
<function>cairo_<emphasis>backend</emphasis>_surface_create(<!-- -->)</function>.</para>
<para>Most surface types allow accessing the surface without using Cairo
functions. If you do this, keep in mind that it is mandatory that you call
<link linkend="cairo-surface-flush"><function>cairo_surface_flush()</function></link> before reading from or writing to the surface and that
you must use <link linkend="cairo-surface-mark-dirty"><function>cairo_surface_mark_dirty()</function></link> after modifying it.</para>
<example>
<title>Directly modifying an image surface</title>
<programlisting>
void
modify_image_surface (cairo_surface_t *surface)
{
  unsigned char *data;
  int width, height, stride;

  // flush to ensure all writing to the image was done
  cairo_surface_flush (surface);

  // modify the image
  data = cairo_image_surface_get_data (surface);
  width = cairo_image_surface_get_width (surface);
  height = cairo_image_surface_get_height (surface);
  stride = cairo_image_surface_get_stride (surface);
  modify_image_data (data, width, height, stride);

  // mark the image dirty so Cairo clears its caches.
  cairo_surface_mark_dirty (surface);
}
</programlisting>
</example>
<para>Note that for other surface types it might be necessary to acquire the
surface's device first. See <link linkend="cairo-device-acquire"><function>cairo_device_acquire()</function></link> for a discussion of
devices.</para>

</refsect1>
<refsect1 id="cairo-cairo-surface-t.functions_details" role="details">
<title role="details.title">Functions</title>
<refsect2 id="cairo-surface-create-similar" role="function" condition="since:1.0">
<title>cairo_surface_create_similar&#160;()</title>
<indexterm zone="cairo-surface-create-similar" role="1.0"><primary sortas="surface_create_similar">cairo_surface_create_similar</primary></indexterm>
<programlisting language="C"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
cairo_surface_create_similar (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *other</parameter>,
                              <parameter><link linkend="cairo-content-t"><type>cairo_content_t</type></link> content</parameter>,
                              <parameter><link linkend="int"><type>int</type></link> width</parameter>,
                              <parameter><link linkend="int"><type>int</type></link> height</parameter>);</programlisting>
<para>Create a new surface that is as compatible as possible with an
existing surface. For example the new surface will have the same
device scale, fallback resolution and font options as
<parameter>other</parameter>
. Generally, the new surface will also use the same backend
as <parameter>other</parameter>
, unless that is not possible for some reason. The type of
the returned surface may be examined with
<link linkend="cairo-surface-get-type"><function>cairo_surface_get_type()</function></link>.</para>
<para>Initially the surface contents are all 0 (transparent if contents
have transparency, black otherwise.)</para>
<para>Use <link linkend="cairo-surface-create-similar-image"><function>cairo_surface_create_similar_image()</function></link> if you need an image surface
which can be painted quickly to the target surface.</para>
<refsect3 id="cairo-surface-create-similar.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>other</para></entry>
<entry role="parameter_description"><para>an existing surface used to select the backend of the new surface</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>content</para></entry>
<entry role="parameter_description"><para>the content for the new surface</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>width</para></entry>
<entry role="parameter_description"><para>width of the new surface, (in device-space units)</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>height</para></entry>
<entry role="parameter_description"><para>height of the new surface (in device-space units)</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-create-similar.returns" role="returns">
<title>Returns</title>
<para> a pointer to the newly allocated surface. The caller
owns the surface and should call <link linkend="cairo-surface-destroy"><function>cairo_surface_destroy()</function></link> when done
with it.</para>
<para>This function always returns a valid pointer, but it will return a
pointer to a "nil" surface if <parameter>other</parameter>
is already in an error state
or any other error occurs.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-create-similar-image" role="function" condition="since:1.12">
<title>cairo_surface_create_similar_image&#160;()</title>
<indexterm zone="cairo-surface-create-similar-image" role="1.12"><primary sortas="surface_create_similar_image">cairo_surface_create_similar_image</primary></indexterm>
<programlisting language="C"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
cairo_surface_create_similar_image (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *other</parameter>,
                                    <parameter><link linkend="cairo-format-t"><type>cairo_format_t</type></link> format</parameter>,
                                    <parameter><link linkend="int"><type>int</type></link> width</parameter>,
                                    <parameter><link linkend="int"><type>int</type></link> height</parameter>);</programlisting>
<para>Create a new image surface that is as compatible as possible for uploading
to and the use in conjunction with an existing surface. However, this surface
can still be used like any normal image surface. Unlike
<link linkend="cairo-surface-create-similar"><function>cairo_surface_create_similar()</function></link> the new image surface won't inherit
the device scale from <parameter>other</parameter>
.</para>
<para>Initially the surface contents are all 0 (transparent if contents
have transparency, black otherwise.)</para>
<para>Use <link linkend="cairo-surface-create-similar"><function>cairo_surface_create_similar()</function></link> if you don't need an image surface.</para>
<refsect3 id="cairo-surface-create-similar-image.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>other</para></entry>
<entry role="parameter_description"><para>an existing surface used to select the preference of the new surface</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>format</para></entry>
<entry role="parameter_description"><para>the format for the new surface</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>width</para></entry>
<entry role="parameter_description"><para>width of the new surface, (in pixels)</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>height</para></entry>
<entry role="parameter_description"><para>height of the new surface (in pixels)</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-create-similar-image.returns" role="returns">
<title>Returns</title>
<para> a pointer to the newly allocated image surface. The caller
owns the surface and should call <link linkend="cairo-surface-destroy"><function>cairo_surface_destroy()</function></link> when done
with it.</para>
<para>This function always returns a valid pointer, but it will return a
pointer to a "nil" surface if <parameter>other</parameter>
is already in an error state
or any other error occurs.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.12">1.12</link></para></refsect2>
<refsect2 id="cairo-surface-create-for-rectangle" role="function" condition="since:1.10">
<title>cairo_surface_create_for_rectangle&#160;()</title>
<indexterm zone="cairo-surface-create-for-rectangle" role="1.10"><primary sortas="surface_create_for_rectangle">cairo_surface_create_for_rectangle</primary></indexterm>
<programlisting language="C"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
cairo_surface_create_for_rectangle (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *target</parameter>,
                                    <parameter><link linkend="double"><type>double</type></link> x</parameter>,
                                    <parameter><link linkend="double"><type>double</type></link> y</parameter>,
                                    <parameter><link linkend="double"><type>double</type></link> width</parameter>,
                                    <parameter><link linkend="double"><type>double</type></link> height</parameter>);</programlisting>
<para>Create a new surface that is a rectangle within the target surface.
All operations drawn to this surface are then clipped and translated
onto the target surface. Nothing drawn via this sub-surface outside of
its bounds is drawn onto the target surface, making this a useful method
for passing constrained child surfaces to library routines that draw
directly onto the parent surface, i.e. with no further backend allocations,
double buffering or copies.</para>
<note><para>The semantics of subsurfaces have not been finalized yet
unless the rectangle is in full device units, is contained within
the extents of the target surface, and the target or subsurface's
device transforms are not changed.</para></note>
<refsect3 id="cairo-surface-create-for-rectangle.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>target</para></entry>
<entry role="parameter_description"><para>an existing surface for which the sub-surface will point to</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>x</para></entry>
<entry role="parameter_description"><para>the x-origin of the sub-surface from the top-left of the target surface (in device-space units)</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>y</para></entry>
<entry role="parameter_description"><para>the y-origin of the sub-surface from the top-left of the target surface (in device-space units)</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>width</para></entry>
<entry role="parameter_description"><para>width of the sub-surface (in device-space units)</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>height</para></entry>
<entry role="parameter_description"><para>height of the sub-surface (in device-space units)</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-create-for-rectangle.returns" role="returns">
<title>Returns</title>
<para> a pointer to the newly allocated surface. The caller
owns the surface and should call <link linkend="cairo-surface-destroy"><function>cairo_surface_destroy()</function></link> when done
with it.</para>
<para>This function always returns a valid pointer, but it will return a
pointer to a "nil" surface if <parameter>other</parameter>
is already in an error state
or any other error occurs.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.10">1.10</link></para></refsect2>
<refsect2 id="cairo-surface-reference" role="function" condition="since:1.0">
<title>cairo_surface_reference&#160;()</title>
<indexterm zone="cairo-surface-reference" role="1.0"><primary sortas="surface_reference">cairo_surface_reference</primary></indexterm>
<programlisting language="C"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
cairo_surface_reference (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Increases the reference count on <parameter>surface</parameter>
 by one. This prevents
<parameter>surface</parameter>
 from being destroyed until a matching call to
<link linkend="cairo-surface-destroy"><function>cairo_surface_destroy()</function></link> is made.</para>
<para>Use <link linkend="cairo-surface-get-reference-count"><function>cairo_surface_get_reference_count()</function></link> to get the number of
references to a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>.</para>
<refsect3 id="cairo-surface-reference.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-reference.returns" role="returns">
<title>Returns</title>
<para> the referenced <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-destroy" role="function" condition="since:1.0">
<title>cairo_surface_destroy&#160;()</title>
<indexterm zone="cairo-surface-destroy" role="1.0"><primary sortas="surface_destroy">cairo_surface_destroy</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_destroy (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Decreases the reference count on <parameter>surface</parameter>
 by one. If the result is
zero, then <parameter>surface</parameter>
 and all associated resources are freed.  See
<link linkend="cairo-surface-reference"><function>cairo_surface_reference()</function></link>.</para>
<refsect3 id="cairo-surface-destroy.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-status" role="function" condition="since:1.0">
<title>cairo_surface_status&#160;()</title>
<indexterm zone="cairo-surface-status" role="1.0"><primary sortas="surface_status">cairo_surface_status</primary></indexterm>
<programlisting language="C"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>
cairo_surface_status (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Checks whether an error has previously occurred for this
surface.</para>
<refsect3 id="cairo-surface-status.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-status.returns" role="returns">
<title>Returns</title>
<para> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link>, <link linkend="CAIRO-STATUS-NULL-POINTER:CAPS"><literal>CAIRO_STATUS_NULL_POINTER</literal></link>,
<link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link>, <link linkend="CAIRO-STATUS-READ-ERROR:CAPS"><literal>CAIRO_STATUS_READ_ERROR</literal></link>,
<link linkend="CAIRO-STATUS-INVALID-CONTENT:CAPS"><literal>CAIRO_STATUS_INVALID_CONTENT</literal></link>, <link linkend="CAIRO-STATUS-INVALID-FORMAT:CAPS"><literal>CAIRO_STATUS_INVALID_FORMAT</literal></link>, or
<link linkend="CAIRO-STATUS-INVALID-VISUAL:CAPS"><literal>CAIRO_STATUS_INVALID_VISUAL</literal></link>.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-finish" role="function" condition="since:1.0">
<title>cairo_surface_finish&#160;()</title>
<indexterm zone="cairo-surface-finish" role="1.0"><primary sortas="surface_finish">cairo_surface_finish</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_finish (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>This function finishes the surface and drops all references to
external resources.  For example, for the Xlib backend it means
that cairo will no longer access the drawable, which can be freed.
After calling <link linkend="cairo-surface-finish"><function>cairo_surface_finish()</function></link> the only valid operations on a
surface are getting and setting user, referencing and
destroying, and flushing and finishing it.
Further drawing to the surface will not affect the
surface but will instead trigger a <link linkend="CAIRO-STATUS-SURFACE-FINISHED:CAPS"><literal>CAIRO_STATUS_SURFACE_FINISHED</literal></link>
error.</para>
<para>When the last call to <link linkend="cairo-surface-destroy"><function>cairo_surface_destroy()</function></link> decreases the
reference count to zero, cairo will call <link linkend="cairo-surface-finish"><function>cairo_surface_finish()</function></link> if
it hasn't been called already, before freeing the resources
associated with the surface.</para>
<refsect3 id="cairo-surface-finish.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>the <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> to finish</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-flush" role="function" condition="since:1.0">
<title>cairo_surface_flush&#160;()</title>
<indexterm zone="cairo-surface-flush" role="1.0"><primary sortas="surface_flush">cairo_surface_flush</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_flush (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Do any pending drawing for the surface and also restore any temporary
modifications cairo has made to the surface's state. This function
must be called before switching from drawing on the surface with
cairo to drawing on it directly with native APIs, or accessing its
memory outside of Cairo. If the surface doesn't support direct
access, then this function does nothing.</para>
<refsect3 id="cairo-surface-flush.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-get-device" role="function" condition="since:1.10">
<title>cairo_surface_get_device&#160;()</title>
<indexterm zone="cairo-surface-get-device" role="1.10"><primary sortas="surface_get_device">cairo_surface_get_device</primary></indexterm>
<programlisting language="C"><link linkend="cairo-device-t"><returnvalue>cairo_device_t</returnvalue></link>&#160;*
cairo_surface_get_device (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>This function returns the device for a <parameter>surface</parameter>
.
See <link linkend="cairo-device-t"><type>cairo_device_t</type></link>.</para>
<refsect3 id="cairo-surface-get-device.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-get-device.returns" role="returns">
<title>Returns</title>
<para> The device for <parameter>surface</parameter>
or <link linkend="NULL:CAPS"><literal>NULL</literal></link> if the surface does
not have an associated device.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.10">1.10</link></para></refsect2>
<refsect2 id="cairo-surface-get-font-options" role="function" condition="since:1.0">
<title>cairo_surface_get_font_options&#160;()</title>
<indexterm zone="cairo-surface-get-font-options" role="1.0"><primary sortas="surface_get_font_options">cairo_surface_get_font_options</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_get_font_options (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                <parameter><link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> *options</parameter>);</programlisting>
<para>Retrieves the default font rendering options for the surface.
This allows display surfaces to report the correct subpixel order
for rendering on them, print surfaces to disable hinting of
metrics and so forth. The result can then be used with
<link linkend="cairo-scaled-font-create"><function>cairo_scaled_font_create()</function></link>.</para>
<refsect3 id="cairo-surface-get-font-options.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>options</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> object into which to store
the retrieved options. All existing values are overwritten</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-get-content" role="function" condition="since:1.2">
<title>cairo_surface_get_content&#160;()</title>
<indexterm zone="cairo-surface-get-content" role="1.2"><primary sortas="surface_get_content">cairo_surface_get_content</primary></indexterm>
<programlisting language="C"><link linkend="cairo-content-t"><returnvalue>cairo_content_t</returnvalue></link>
cairo_surface_get_content (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>This function returns the content type of <parameter>surface</parameter>
 which indicates
whether the surface contains color and/or alpha information. See
<link linkend="cairo-content-t"><type>cairo_content_t</type></link>.</para>
<refsect3 id="cairo-surface-get-content.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-get-content.returns" role="returns">
<title>Returns</title>
<para> The content type of <parameter>surface</parameter>
.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.2">1.2</link></para></refsect2>
<refsect2 id="cairo-surface-mark-dirty" role="function" condition="since:1.0">
<title>cairo_surface_mark_dirty&#160;()</title>
<indexterm zone="cairo-surface-mark-dirty" role="1.0"><primary sortas="surface_mark_dirty">cairo_surface_mark_dirty</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_mark_dirty (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Tells cairo that drawing has been done to surface using means other
than cairo, and that cairo should reread any cached areas. Note
that you must call <link linkend="cairo-surface-flush"><function>cairo_surface_flush()</function></link> before doing such drawing.</para>
<refsect3 id="cairo-surface-mark-dirty.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-mark-dirty-rectangle" role="function" condition="since:1.0">
<title>cairo_surface_mark_dirty_rectangle&#160;()</title>
<indexterm zone="cairo-surface-mark-dirty-rectangle" role="1.0"><primary sortas="surface_mark_dirty_rectangle">cairo_surface_mark_dirty_rectangle</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_mark_dirty_rectangle (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                    <parameter><link linkend="int"><type>int</type></link> x</parameter>,
                                    <parameter><link linkend="int"><type>int</type></link> y</parameter>,
                                    <parameter><link linkend="int"><type>int</type></link> width</parameter>,
                                    <parameter><link linkend="int"><type>int</type></link> height</parameter>);</programlisting>
<para>Like <link linkend="cairo-surface-mark-dirty"><function>cairo_surface_mark_dirty()</function></link>, but drawing has been done only to
the specified rectangle, so that cairo can retain cached contents
for other parts of the surface.</para>
<para>Any cached clip set on the surface will be reset by this function,
to make sure that future cairo calls have the clip set that they
expect.</para>
<refsect3 id="cairo-surface-mark-dirty-rectangle.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>x</para></entry>
<entry role="parameter_description"><para>X coordinate of dirty rectangle</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>y</para></entry>
<entry role="parameter_description"><para>Y coordinate of dirty rectangle</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>width</para></entry>
<entry role="parameter_description"><para>width of dirty rectangle</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>height</para></entry>
<entry role="parameter_description"><para>height of dirty rectangle</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-set-device-offset" role="function" condition="since:1.0">
<title>cairo_surface_set_device_offset&#160;()</title>
<indexterm zone="cairo-surface-set-device-offset" role="1.0"><primary sortas="surface_set_device_offset">cairo_surface_set_device_offset</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_set_device_offset (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                 <parameter><link linkend="double"><type>double</type></link> x_offset</parameter>,
                                 <parameter><link linkend="double"><type>double</type></link> y_offset</parameter>);</programlisting>
<para>Sets an offset that is added to the device coordinates determined
by the CTM when drawing to <parameter>surface</parameter>
. One use case for this function
is when we want to create a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> that redirects drawing
for a portion of an onscreen surface to an offscreen surface in a
way that is completely invisible to the user of the cairo
API. Setting a transformation via <link linkend="cairo-translate"><function>cairo_translate()</function></link> isn't
sufficient to do this, since functions like
<link linkend="cairo-device-to-user"><function>cairo_device_to_user()</function></link> will expose the hidden offset.</para>
<para>Note that the offset affects drawing to the surface as well as
using the surface in a source pattern.</para>
<refsect3 id="cairo-surface-set-device-offset.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>x_offset</para></entry>
<entry role="parameter_description"><para>the offset in the X direction, in device units</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>y_offset</para></entry>
<entry role="parameter_description"><para>the offset in the Y direction, in device units</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-get-device-offset" role="function" condition="since:1.2">
<title>cairo_surface_get_device_offset&#160;()</title>
<indexterm zone="cairo-surface-get-device-offset" role="1.2"><primary sortas="surface_get_device_offset">cairo_surface_get_device_offset</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_get_device_offset (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                 <parameter><link linkend="double"><type>double</type></link> *x_offset</parameter>,
                                 <parameter><link linkend="double"><type>double</type></link> *y_offset</parameter>);</programlisting>
<para>This function returns the previous device offset set by
<link linkend="cairo-surface-set-device-offset"><function>cairo_surface_set_device_offset()</function></link>.</para>
<refsect3 id="cairo-surface-get-device-offset.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>x_offset</para></entry>
<entry role="parameter_description"><para>the offset in the X direction, in device units</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>y_offset</para></entry>
<entry role="parameter_description"><para>the offset in the Y direction, in device units</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.2">1.2</link></para></refsect2>
<refsect2 id="cairo-surface-get-device-scale" role="function" condition="since:1.14">
<title>cairo_surface_get_device_scale&#160;()</title>
<indexterm zone="cairo-surface-get-device-scale" role="1.14"><primary sortas="surface_get_device_scale">cairo_surface_get_device_scale</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_get_device_scale (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                <parameter><link linkend="double"><type>double</type></link> *x_scale</parameter>,
                                <parameter><link linkend="double"><type>double</type></link> *y_scale</parameter>);</programlisting>
<para>This function returns the previous device offset set by
<link linkend="cairo-surface-set-device-scale"><function>cairo_surface_set_device_scale()</function></link>.</para>
<refsect3 id="cairo-surface-get-device-scale.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>x_scale</para></entry>
<entry role="parameter_description"><para>the scale in the X direction, in device units</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>y_scale</para></entry>
<entry role="parameter_description"><para>the scale in the Y direction, in device units</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.14">1.14</link></para></refsect2>
<refsect2 id="cairo-surface-set-device-scale" role="function" condition="since:1.14">
<title>cairo_surface_set_device_scale&#160;()</title>
<indexterm zone="cairo-surface-set-device-scale" role="1.14"><primary sortas="surface_set_device_scale">cairo_surface_set_device_scale</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_set_device_scale (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                <parameter><link linkend="double"><type>double</type></link> x_scale</parameter>,
                                <parameter><link linkend="double"><type>double</type></link> y_scale</parameter>);</programlisting>
<para>Sets a scale that is multiplied to the device coordinates determined
by the CTM when drawing to <parameter>surface</parameter>
. One common use for this is to
render to very high resolution display devices at a scale factor, so
that code that assumes 1 pixel will be a certain size will still work.
Setting a transformation via <link linkend="cairo-translate"><function>cairo_translate()</function></link> isn't
sufficient to do this, since functions like
<link linkend="cairo-device-to-user"><function>cairo_device_to_user()</function></link> will expose the hidden scale.</para>
<para>Note that the scale affects drawing to the surface as well as
using the surface in a source pattern.</para>
<refsect3 id="cairo-surface-set-device-scale.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>x_scale</para></entry>
<entry role="parameter_description"><para>a scale factor in the X direction</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>y_scale</para></entry>
<entry role="parameter_description"><para>a scale factor in the Y direction</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.14">1.14</link></para></refsect2>
<refsect2 id="cairo-surface-set-fallback-resolution" role="function" condition="since:1.2">
<title>cairo_surface_set_fallback_resolution&#160;()</title>
<indexterm zone="cairo-surface-set-fallback-resolution" role="1.2"><primary sortas="surface_set_fallback_resolution">cairo_surface_set_fallback_resolution</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_set_fallback_resolution (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                       <parameter><link linkend="double"><type>double</type></link> x_pixels_per_inch</parameter>,
                                       <parameter><link linkend="double"><type>double</type></link> y_pixels_per_inch</parameter>);</programlisting>
<para>Set the horizontal and vertical resolution for image fallbacks.</para>
<para>When certain operations aren't supported natively by a backend,
cairo will fallback by rendering operations to an image and then
overlaying that image onto the output. For backends that are
natively vector-oriented, this function can be used to set the
resolution used for these image fallbacks, (larger values will
result in more detailed images, but also larger file sizes).</para>
<para>Some examples of natively vector-oriented backends are the ps, pdf,
and svg backends.</para>
<para>For backends that are natively raster-oriented, image fallbacks are
still possible, but they are always performed at the native
device resolution. So this function has no effect on those
backends.</para>
<para>Note: The fallback resolution only takes effect at the time of
completing a page (with <link linkend="cairo-show-page"><function>cairo_show_page()</function></link> or <link linkend="cairo-copy-page"><function>cairo_copy_page()</function></link>) so
there is currently no way to have more than one fallback resolution
in effect on a single page.</para>
<para>The default fallback resoultion is 300 pixels per inch in both
dimensions.</para>
<refsect3 id="cairo-surface-set-fallback-resolution.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>x_pixels_per_inch</para></entry>
<entry role="parameter_description"><para>horizontal setting for pixels per inch</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>y_pixels_per_inch</para></entry>
<entry role="parameter_description"><para>vertical setting for pixels per inch</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.2">1.2</link></para></refsect2>
<refsect2 id="cairo-surface-get-fallback-resolution" role="function" condition="since:1.8">
<title>cairo_surface_get_fallback_resolution&#160;()</title>
<indexterm zone="cairo-surface-get-fallback-resolution" role="1.8"><primary sortas="surface_get_fallback_resolution">cairo_surface_get_fallback_resolution</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_get_fallback_resolution (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                       <parameter><link linkend="double"><type>double</type></link> *x_pixels_per_inch</parameter>,
                                       <parameter><link linkend="double"><type>double</type></link> *y_pixels_per_inch</parameter>);</programlisting>
<para>This function returns the previous fallback resolution set by
<link linkend="cairo-surface-set-fallback-resolution"><function>cairo_surface_set_fallback_resolution()</function></link>, or default fallback
resolution if never set.</para>
<refsect3 id="cairo-surface-get-fallback-resolution.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>x_pixels_per_inch</para></entry>
<entry role="parameter_description"><para>horizontal pixels per inch</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>y_pixels_per_inch</para></entry>
<entry role="parameter_description"><para>vertical pixels per inch</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.8">1.8</link></para></refsect2>
<refsect2 id="cairo-surface-get-type" role="function" condition="since:1.2">
<title>cairo_surface_get_type&#160;()</title>
<indexterm zone="cairo-surface-get-type" role="1.2"><primary sortas="surface_get_type">cairo_surface_get_type</primary></indexterm>
<programlisting language="C"><link linkend="cairo-surface-type-t"><returnvalue>cairo_surface_type_t</returnvalue></link>
cairo_surface_get_type (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>This function returns the type of the backend used to create
a surface. See <link linkend="cairo-surface-type-t"><type>cairo_surface_type_t</type></link> for available types.</para>
<refsect3 id="cairo-surface-get-type.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-get-type.returns" role="returns">
<title>Returns</title>
<para> The type of <parameter>surface</parameter>
.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.2">1.2</link></para></refsect2>
<refsect2 id="cairo-surface-get-reference-count" role="function" condition="since:1.4">
<title>cairo_surface_get_reference_count&#160;()</title>
<indexterm zone="cairo-surface-get-reference-count" role="1.4"><primary sortas="surface_get_reference_count">cairo_surface_get_reference_count</primary></indexterm>
<programlisting language="C">unsigned <link linkend="int"><returnvalue>int</returnvalue></link>
cairo_surface_get_reference_count (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Returns the current reference count of <parameter>surface</parameter>
.</para>
<refsect3 id="cairo-surface-get-reference-count.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-get-reference-count.returns" role="returns">
<title>Returns</title>
<para> the current reference count of <parameter>surface</parameter>
.  If the
object is a nil object, 0 will be returned.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.4">1.4</link></para></refsect2>
<refsect2 id="cairo-surface-set-user-data" role="function" condition="since:1.0">
<title>cairo_surface_set_user_data&#160;()</title>
<indexterm zone="cairo-surface-set-user-data" role="1.0"><primary sortas="surface_set_user_data">cairo_surface_set_user_data</primary></indexterm>
<programlisting language="C"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>
cairo_surface_set_user_data (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                             <parameter>const <link linkend="cairo-user-data-key-t"><type>cairo_user_data_key_t</type></link> *key</parameter>,
                             <parameter><link linkend="void"><type>void</type></link> *user_data</parameter>,
                             <parameter><link linkend="cairo-destroy-func-t"><type>cairo_destroy_func_t</type></link> destroy</parameter>);</programlisting>
<para>Attach user data to <parameter>surface</parameter>
.  To remove user data from a surface,
call this function with the key that was used to set it and <link linkend="NULL:CAPS"><literal>NULL</literal></link>
for <parameter>data</parameter>
.</para>
<refsect3 id="cairo-surface-set-user-data.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>key</para></entry>
<entry role="parameter_description"><para>the address of a <link linkend="cairo-user-data-key-t"><type>cairo_user_data_key_t</type></link> to attach the user data to</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>user_data</para></entry>
<entry role="parameter_description"><para>the user data to attach to the surface</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>destroy</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-destroy-func-t"><type>cairo_destroy_func_t</type></link> which will be called when the
surface is destroyed or when new user data is attached using the
same key.</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-set-user-data.returns" role="returns">
<title>Returns</title>
<para> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link> or <link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link> if a
slot could not be allocated for the user data.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-get-user-data" role="function" condition="since:1.0">
<title>cairo_surface_get_user_data&#160;()</title>
<indexterm zone="cairo-surface-get-user-data" role="1.0"><primary sortas="surface_get_user_data">cairo_surface_get_user_data</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>&#160;*
cairo_surface_get_user_data (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                             <parameter>const <link linkend="cairo-user-data-key-t"><type>cairo_user_data_key_t</type></link> *key</parameter>);</programlisting>
<para>Return user data previously attached to <parameter>surface</parameter>
 using the specified
key.  If no user data has been attached with the given key this
function returns <link linkend="NULL:CAPS"><literal>NULL</literal></link>.</para>
<refsect3 id="cairo-surface-get-user-data.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>key</para></entry>
<entry role="parameter_description"><para>the address of the <link linkend="cairo-user-data-key-t"><type>cairo_user_data_key_t</type></link> the user data was
attached to</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-get-user-data.returns" role="returns">
<title>Returns</title>
<para> the user data previously attached or <link linkend="NULL:CAPS"><literal>NULL</literal></link>.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-copy-page" role="function" condition="since:1.6">
<title>cairo_surface_copy_page&#160;()</title>
<indexterm zone="cairo-surface-copy-page" role="1.6"><primary sortas="surface_copy_page">cairo_surface_copy_page</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_copy_page (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Emits the current page for backends that support multiple pages,
but doesn't clear it, so that the contents of the current page will
be retained for the next page.  Use <link linkend="cairo-surface-show-page"><function>cairo_surface_show_page()</function></link> if you
want to get an empty page after the emission.</para>
<para>There is a convenience function for this that takes a <link linkend="cairo-t"><type>cairo_t</type></link>,
namely <link linkend="cairo-copy-page"><function>cairo_copy_page()</function></link>.</para>
<refsect3 id="cairo-surface-copy-page.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.6">1.6</link></para></refsect2>
<refsect2 id="cairo-surface-show-page" role="function" condition="since:1.6">
<title>cairo_surface_show_page&#160;()</title>
<indexterm zone="cairo-surface-show-page" role="1.6"><primary sortas="surface_show_page">cairo_surface_show_page</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_show_page (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Emits and clears the current page for backends that support multiple
pages.  Use <link linkend="cairo-surface-copy-page"><function>cairo_surface_copy_page()</function></link> if you don't want to clear the page.</para>
<para>There is a convenience function for this that takes a <link linkend="cairo-t"><type>cairo_t</type></link>,
namely <link linkend="cairo-show-page"><function>cairo_show_page()</function></link>.</para>
<refsect3 id="cairo-surface-show-page.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-Surface-t"><type>cairo_Surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.6">1.6</link></para></refsect2>
<refsect2 id="cairo-surface-has-show-text-glyphs" role="function" condition="since:1.8">
<title>cairo_surface_has_show_text_glyphs&#160;()</title>
<indexterm zone="cairo-surface-has-show-text-glyphs" role="1.8"><primary sortas="surface_has_show_text_glyphs">cairo_surface_has_show_text_glyphs</primary></indexterm>
<programlisting language="C"><link linkend="cairo-bool-t"><returnvalue>cairo_bool_t</returnvalue></link>
cairo_surface_has_show_text_glyphs (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);</programlisting>
<para>Returns whether the surface supports
sophisticated <link linkend="cairo-show-text-glyphs"><function>cairo_show_text_glyphs()</function></link> operations.  That is,
whether it actually uses the provided text and cluster data
to a <link linkend="cairo-show-text-glyphs"><function>cairo_show_text_glyphs()</function></link> call.</para>
<para>Note: Even if this function returns <link linkend="FALSE:CAPS"><literal>FALSE</literal></link>, a
<link linkend="cairo-show-text-glyphs"><function>cairo_show_text_glyphs()</function></link> operation targeted at <parameter>surface</parameter>
 will
still succeed.  It just will
act like a <link linkend="cairo-show-glyphs"><function>cairo_show_glyphs()</function></link> operation.  Users can use this
function to avoid computing UTF-8 text and cluster mapping if the
target surface does not use it.</para>
<refsect3 id="cairo-surface-has-show-text-glyphs.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-has-show-text-glyphs.returns" role="returns">
<title>Returns</title>
<para> <link linkend="TRUE:CAPS"><literal>TRUE</literal></link> if <parameter>surface</parameter>
supports
<link linkend="cairo-show-text-glyphs"><function>cairo_show_text_glyphs()</function></link>, <link linkend="FALSE:CAPS"><literal>FALSE</literal></link> otherwise</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.8">1.8</link></para></refsect2>
<refsect2 id="cairo-surface-set-mime-data" role="function" condition="since:1.10">
<title>cairo_surface_set_mime_data&#160;()</title>
<indexterm zone="cairo-surface-set-mime-data" role="1.10"><primary sortas="surface_set_mime_data">cairo_surface_set_mime_data</primary></indexterm>
<programlisting language="C"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>
cairo_surface_set_mime_data (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                             <parameter>const <link linkend="char"><type>char</type></link> *mime_type</parameter>,
                             <parameter>const unsigned <link linkend="char"><type>char</type></link> *data</parameter>,
                             <parameter><type>unsigned long </type> length</parameter>,
                             <parameter><link linkend="cairo-destroy-func-t"><type>cairo_destroy_func_t</type></link> destroy</parameter>,
                             <parameter><link linkend="void"><type>void</type></link> *closure</parameter>);</programlisting>
<para>Attach an image in the format <parameter>mime_type</parameter>
 to <parameter>surface</parameter>
. To remove
the data from a surface, call this function with same mime type
and <link linkend="NULL:CAPS"><literal>NULL</literal></link> for <parameter>data</parameter>
.</para>
<para>The attached image (or filename) data can later be used by backends
which support it (currently: PDF, PS, SVG and Win32 Printing
surfaces) to emit this data instead of making a snapshot of the
<parameter>surface</parameter>
.  This approach tends to be faster and requires less
memory and disk space.</para>
<para>The recognized MIME types are the following: <link linkend="CAIRO-MIME-TYPE-JPEG:CAPS"><literal>CAIRO_MIME_TYPE_JPEG</literal></link>,
<link linkend="CAIRO-MIME-TYPE-PNG:CAPS"><literal>CAIRO_MIME_TYPE_PNG</literal></link>, <link linkend="CAIRO-MIME-TYPE-JP2:CAPS"><literal>CAIRO_MIME_TYPE_JP2</literal></link>, <link linkend="CAIRO-MIME-TYPE-URI:CAPS"><literal>CAIRO_MIME_TYPE_URI</literal></link>,
<link linkend="CAIRO-MIME-TYPE-UNIQUE-ID:CAPS"><literal>CAIRO_MIME_TYPE_UNIQUE_ID</literal></link>, <link linkend="CAIRO-MIME-TYPE-JBIG2:CAPS"><literal>CAIRO_MIME_TYPE_JBIG2</literal></link>,
<link linkend="CAIRO-MIME-TYPE-JBIG2-GLOBAL:CAPS"><literal>CAIRO_MIME_TYPE_JBIG2_GLOBAL</literal></link>, <link linkend="CAIRO-MIME-TYPE-JBIG2-GLOBAL-ID:CAPS"><literal>CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID</literal></link>,
<link linkend="CAIRO-MIME-TYPE-CCITT-FAX:CAPS"><literal>CAIRO_MIME_TYPE_CCITT_FAX</literal></link>, <link linkend="CAIRO-MIME-TYPE-CCITT-FAX-PARAMS:CAPS"><literal>CAIRO_MIME_TYPE_CCITT_FAX_PARAMS</literal></link>.</para>
<para>See corresponding backend surface docs for details about which MIME
types it can handle. Caution: the associated MIME data will be
discarded if you draw on the surface afterwards. Use this function
with care.</para>
<para>Even if a backend supports a MIME type, that does not mean cairo
will always be able to use the attached MIME data. For example, if
the backend does not natively support the compositing operation used
to apply the MIME data to the backend. In that case, the MIME data
will be ignored. Therefore, to apply an image in all cases, it is best
to create an image surface which contains the decoded image data and
then attach the MIME data to that. This ensures the image will always
be used while still allowing the MIME data to be used whenever
possible.</para>
<refsect3 id="cairo-surface-set-mime-data.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>mime_type</para></entry>
<entry role="parameter_description"><para>the MIME type of the image data</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>data</para></entry>
<entry role="parameter_description"><para>the image data to attach to the surface</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>length</para></entry>
<entry role="parameter_description"><para>the length of the image data</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>destroy</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-destroy-func-t"><type>cairo_destroy_func_t</type></link> which will be called when the
surface is destroyed or when new image data is attached using the
same mime type.</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>closure</para></entry>
<entry role="parameter_description"><para>the data to be passed to the <parameter>destroy</parameter>
notifier</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-set-mime-data.returns" role="returns">
<title>Returns</title>
<para> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link> or <link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link> if a
slot could not be allocated for the user data.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.10">1.10</link></para></refsect2>
<refsect2 id="cairo-surface-get-mime-data" role="function" condition="since:1.10">
<title>cairo_surface_get_mime_data&#160;()</title>
<indexterm zone="cairo-surface-get-mime-data" role="1.10"><primary sortas="surface_get_mime_data">cairo_surface_get_mime_data</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_get_mime_data (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                             <parameter>const <link linkend="char"><type>char</type></link> *mime_type</parameter>,
                             <parameter>const unsigned <link linkend="char"><type>char</type></link> **data</parameter>,
                             <parameter>unsigned <link linkend="long"><type>long</type></link> *length</parameter>);</programlisting>
<para>Return mime data previously attached to <parameter>surface</parameter>
 using the
specified mime type.  If no data has been attached with the given
mime type, <parameter>data</parameter>
 is set <link linkend="NULL:CAPS"><literal>NULL</literal></link>.</para>
<refsect3 id="cairo-surface-get-mime-data.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>mime_type</para></entry>
<entry role="parameter_description"><para>the mime type of the image data</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>data</para></entry>
<entry role="parameter_description"><para>the image data to attached to the surface</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>length</para></entry>
<entry role="parameter_description"><para>the length of the image data</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.10">1.10</link></para></refsect2>
<refsect2 id="cairo-surface-supports-mime-type" role="function" condition="since:1.12">
<title>cairo_surface_supports_mime_type&#160;()</title>
<indexterm zone="cairo-surface-supports-mime-type" role="1.12"><primary sortas="surface_supports_mime_type">cairo_surface_supports_mime_type</primary></indexterm>
<programlisting language="C"><link linkend="cairo-bool-t"><returnvalue>cairo_bool_t</returnvalue></link>
cairo_surface_supports_mime_type (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                                  <parameter>const <link linkend="char"><type>char</type></link> *mime_type</parameter>);</programlisting>
<para>Return whether <parameter>surface</parameter>
 supports <parameter>mime_type</parameter>
.</para>
<refsect3 id="cairo-surface-supports-mime-type.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>mime_type</para></entry>
<entry role="parameter_description"><para>the mime type</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-supports-mime-type.returns" role="returns">
<title>Returns</title>
<para> <link linkend="TRUE:CAPS"><literal>TRUE</literal></link> if <parameter>surface</parameter>
supports
<parameter>mime_type</parameter>
, <link linkend="FALSE:CAPS"><literal>FALSE</literal></link> otherwise</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.12">1.12</link></para></refsect2>
<refsect2 id="cairo-surface-map-to-image" role="function" condition="since:1.12">
<title>cairo_surface_map_to_image&#160;()</title>
<indexterm zone="cairo-surface-map-to-image" role="1.12"><primary sortas="surface_map_to_image">cairo_surface_map_to_image</primary></indexterm>
<programlisting language="C"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link>&#160;*
cairo_surface_map_to_image (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                            <parameter>const <link linkend="cairo-rectangle-int-t"><type>cairo_rectangle_int_t</type></link> *extents</parameter>);</programlisting>
<para>Returns an image surface that is the most efficient mechanism for
modifying the backing store of the target surface. The region retrieved
may be limited to the <parameter>extents</parameter>
 or <link linkend="NULL:CAPS"><literal>NULL</literal></link> for the whole surface</para>
<para>Note, the use of the original surface as a target or source whilst
it is mapped is undefined. The result of mapping the surface
multiple times is undefined. Calling <link linkend="cairo-surface-destroy"><function>cairo_surface_destroy()</function></link> or
<link linkend="cairo-surface-finish"><function>cairo_surface_finish()</function></link> on the resulting image surface results in
undefined behavior. Changing the device transform of the image
surface or of <parameter>surface</parameter>
 before the image surface is unmapped results
in undefined behavior.</para>
<refsect3 id="cairo-surface-map-to-image.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>an existing surface used to extract the image from</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>extents</para></entry>
<entry role="parameter_description"><para>limit the extraction to an rectangular region</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><refsect3 id="cairo-surface-map-to-image.returns" role="returns">
<title>Returns</title>
<para> a pointer to the newly allocated image surface. The caller
must use <link linkend="cairo-surface-unmap-image"><function>cairo_surface_unmap_image()</function></link> to destroy this image surface.</para>
<para>This function always returns a valid pointer, but it will return a
pointer to a "nil" surface if <parameter>other</parameter>
is already in an error state
or any other error occurs. If the returned pointer does not have an
error status, it is guaranteed to be an image surface whose format
is not <link linkend="CAIRO-FORMAT-INVALID:CAPS"><literal>CAIRO_FORMAT_INVALID</literal></link>.</para>
</refsect3><para role="since">Since: <link linkend="api-index-1.12">1.12</link></para></refsect2>
<refsect2 id="cairo-surface-unmap-image" role="function" condition="since:1.12">
<title>cairo_surface_unmap_image&#160;()</title>
<indexterm zone="cairo-surface-unmap-image" role="1.12"><primary sortas="surface_unmap_image">cairo_surface_unmap_image</primary></indexterm>
<programlisting language="C"><link linkend="void"><returnvalue>void</returnvalue></link>
cairo_surface_unmap_image (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>,
                           <parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *image</parameter>);</programlisting>
<para>Unmaps the image surface as returned from <link linkend="cairo-surface-map-to-image"><function><link linkend="cairo-surface-map-to-image"><function>cairo_surface_map_to_image()</function></link></function></link>.</para>
<para>The content of the image will be uploaded to the target surface.
Afterwards, the image is destroyed.</para>
<para>Using an image surface which wasn't returned by <link linkend="cairo-surface-map-to-image"><function>cairo_surface_map_to_image()</function></link>
results in undefined behavior.</para>
<refsect3 id="cairo-surface-unmap-image.parameters" role="parameters">
<title>Parameters</title>
<informaltable role="parameters_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="parameters_name" colwidth="150px"/>
<colspec colname="parameters_description"/>
<colspec colname="parameters_annotations" colwidth="200px"/>
<tbody>
<row><entry role="parameter_name"><para>surface</para></entry>
<entry role="parameter_description"><para>the surface passed to <link linkend="cairo-surface-map-to-image"><function>cairo_surface_map_to_image()</function></link>.</para></entry>
<entry role="parameter_annotations"></entry></row>
<row><entry role="parameter_name"><para>image</para></entry>
<entry role="parameter_description"><para>the currently mapped image</para></entry>
<entry role="parameter_annotations"></entry></row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.12">1.12</link></para></refsect2>

</refsect1>
<refsect1 id="cairo-cairo-surface-t.other_details" role="details">
<title role="details.title">Types and Values</title>
<refsect2 id="CAIRO-HAS-MIME-SURFACE:CAPS" role="macro">
<title>CAIRO_HAS_MIME_SURFACE</title>
<indexterm zone="CAIRO-HAS-MIME-SURFACE:CAPS"><primary sortas="HAS_MIME_SURFACE">CAIRO_HAS_MIME_SURFACE</primary></indexterm>
<programlisting language="C">#define CAIRO_HAS_MIME_SURFACE 1
</programlisting>
</refsect2>
<refsect2 id="CAIRO-MIME-TYPE-CCITT-FAX:CAPS" role="macro" condition="since:1.16">
<title>CAIRO_MIME_TYPE_CCITT_FAX</title>
<indexterm zone="CAIRO-MIME-TYPE-CCITT-FAX:CAPS" role="1.16"><primary sortas="MIME_TYPE_CCITT_FAX">CAIRO_MIME_TYPE_CCITT_FAX</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_CCITT_FAX "image/g3fax"
</programlisting>
<para>Group 3 or Group 4 CCITT facsimile encoding (International
Telecommunication Union, Recommendations T.4 and T.6.)</para>
<para role="since">Since: <link linkend="api-index-1.16">1.16</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-CCITT-FAX-PARAMS:CAPS" role="macro" condition="since:1.16">
<title>CAIRO_MIME_TYPE_CCITT_FAX_PARAMS</title>
<indexterm zone="CAIRO-MIME-TYPE-CCITT-FAX-PARAMS:CAPS" role="1.16"><primary sortas="MIME_TYPE_CCITT_FAX_PARAMS">CAIRO_MIME_TYPE_CCITT_FAX_PARAMS</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_CCITT_FAX_PARAMS "application/x-cairo.ccitt.params"
</programlisting>
<para>Decode parameters for Group 3 or Group 4 CCITT facsimile encoding.
See <link linkend="ccitt">CCITT Fax Images</link>.</para>
<para role="since">Since: <link linkend="api-index-1.16">1.16</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-EPS:CAPS" role="macro" condition="since:1.16">
<title>CAIRO_MIME_TYPE_EPS</title>
<indexterm zone="CAIRO-MIME-TYPE-EPS:CAPS" role="1.16"><primary sortas="MIME_TYPE_EPS">CAIRO_MIME_TYPE_EPS</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_EPS "application/postscript"
</programlisting>
<para>Encapsulated PostScript file.
<ulink url="http://wwwimages.adobe.com/content/dam/Adobe/endevnet/postscript/pdfs/5002.EPSF_Spec.pdf">Encapsulated PostScript File Format Specification</ulink></para>
<para role="since">Since: <link linkend="api-index-1.16">1.16</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-EPS-PARAMS:CAPS" role="macro" condition="since:1.16">
<title>CAIRO_MIME_TYPE_EPS_PARAMS</title>
<indexterm zone="CAIRO-MIME-TYPE-EPS-PARAMS:CAPS" role="1.16"><primary sortas="MIME_TYPE_EPS_PARAMS">CAIRO_MIME_TYPE_EPS_PARAMS</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_EPS_PARAMS "application/x-cairo.eps.params"
</programlisting>
<para>Embedding parameters Encapsulated PostScript data.
See <link linkend="eps">Embedding EPS files</link>.</para>
<para role="since">Since: <link linkend="api-index-1.16">1.16</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-JBIG2:CAPS" role="macro" condition="since:1.14">
<title>CAIRO_MIME_TYPE_JBIG2</title>
<indexterm zone="CAIRO-MIME-TYPE-JBIG2:CAPS" role="1.14"><primary sortas="MIME_TYPE_JBIG2">CAIRO_MIME_TYPE_JBIG2</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_JBIG2 "application/x-cairo.jbig2"
</programlisting>
<para>Joint Bi-level Image Experts Group image coding standard (ISO/IEC 11544).</para>
<para role="since">Since: <link linkend="api-index-1.14">1.14</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-JBIG2-GLOBAL:CAPS" role="macro" condition="since:1.14">
<title>CAIRO_MIME_TYPE_JBIG2_GLOBAL</title>
<indexterm zone="CAIRO-MIME-TYPE-JBIG2-GLOBAL:CAPS" role="1.14"><primary sortas="MIME_TYPE_JBIG2_GLOBAL">CAIRO_MIME_TYPE_JBIG2_GLOBAL</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_JBIG2_GLOBAL "application/x-cairo.jbig2-global"
</programlisting>
<para>Joint Bi-level Image Experts Group image coding standard (ISO/IEC 11544) global segment.</para>
<para role="since">Since: <link linkend="api-index-1.14">1.14</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-JBIG2-GLOBAL-ID:CAPS" role="macro" condition="since:1.14">
<title>CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID</title>
<indexterm zone="CAIRO-MIME-TYPE-JBIG2-GLOBAL-ID:CAPS" role="1.14"><primary sortas="MIME_TYPE_JBIG2_GLOBAL_ID">CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID "application/x-cairo.jbig2-global-id"
</programlisting>
<para>An unique identifier shared by a JBIG2 global segment and all JBIG2 images
that depend on the global segment.</para>
<para role="since">Since: <link linkend="api-index-1.14">1.14</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-JP2:CAPS" role="macro" condition="since:1.10">
<title>CAIRO_MIME_TYPE_JP2</title>
<indexterm zone="CAIRO-MIME-TYPE-JP2:CAPS" role="1.10"><primary sortas="MIME_TYPE_JP2">CAIRO_MIME_TYPE_JP2</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_JP2 "image/jp2"
</programlisting>
<para>The Joint Photographic Experts Group (JPEG) 2000 image coding standard (ISO/IEC 15444-1).</para>
<para role="since">Since: <link linkend="api-index-1.10">1.10</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-JPEG:CAPS" role="macro" condition="since:1.10">
<title>CAIRO_MIME_TYPE_JPEG</title>
<indexterm zone="CAIRO-MIME-TYPE-JPEG:CAPS" role="1.10"><primary sortas="MIME_TYPE_JPEG">CAIRO_MIME_TYPE_JPEG</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_JPEG "image/jpeg"
</programlisting>
<para>The Joint Photographic Experts Group (JPEG) image coding standard (ISO/IEC 10918-1).</para>
<para role="since">Since: <link linkend="api-index-1.10">1.10</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-PNG:CAPS" role="macro" condition="since:1.10">
<title>CAIRO_MIME_TYPE_PNG</title>
<indexterm zone="CAIRO-MIME-TYPE-PNG:CAPS" role="1.10"><primary sortas="MIME_TYPE_PNG">CAIRO_MIME_TYPE_PNG</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_PNG "image/png"
</programlisting>
<para>The Portable Network Graphics image file format (ISO/IEC 15948).</para>
<para role="since">Since: <link linkend="api-index-1.10">1.10</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-URI:CAPS" role="macro" condition="since:1.10">
<title>CAIRO_MIME_TYPE_URI</title>
<indexterm zone="CAIRO-MIME-TYPE-URI:CAPS" role="1.10"><primary sortas="MIME_TYPE_URI">CAIRO_MIME_TYPE_URI</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_URI "text/x-uri"
</programlisting>
<para>URI for an image file (unofficial MIME type).</para>
<para role="since">Since: <link linkend="api-index-1.10">1.10</link></para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-UNIQUE-ID:CAPS" role="macro" condition="since:1.12">
<title>CAIRO_MIME_TYPE_UNIQUE_ID</title>
<indexterm zone="CAIRO-MIME-TYPE-UNIQUE-ID:CAPS" role="1.12"><primary sortas="MIME_TYPE_UNIQUE_ID">CAIRO_MIME_TYPE_UNIQUE_ID</primary></indexterm>
<programlisting language="C">#define CAIRO_MIME_TYPE_UNIQUE_ID "application/x-cairo.uuid"
</programlisting>
<para>Unique identifier for a surface (cairo specific MIME type). All surfaces with
the same unique identifier will only be embedded once.</para>
<para role="since">Since: <link linkend="api-index-1.12">1.12</link></para></refsect2>
<refsect2 id="cairo-surface-t" role="typedef" condition="since:1.0">
<title>cairo_surface_t</title>
<indexterm zone="cairo-surface-t" role="1.0"><primary sortas="surface_t">cairo_surface_t</primary></indexterm>
<programlisting language="C">typedef struct _cairo_surface cairo_surface_t;
</programlisting>
<para>A <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> represents an image, either as the destination
of a drawing operation or as source when drawing onto another
surface.  To draw to a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>, create a cairo context
with the surface as the target, using <link linkend="cairo-create"><function>cairo_create()</function></link>.</para>
<para>There are different subtypes of <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> for
different drawing backends; for example, <link linkend="cairo-image-surface-create"><function>cairo_image_surface_create()</function></link>
creates a bitmap image in memory.
The type of a surface can be queried with <link linkend="cairo-surface-get-type"><function>cairo_surface_get_type()</function></link>.</para>
<para>The initial contents of a surface after creation depend upon the manner
of its creation. If cairo creates the surface and backing storage for
the user, it will be initially cleared; for example,
<link linkend="cairo-image-surface-create"><function>cairo_image_surface_create()</function></link> and <link linkend="cairo-surface-create-similar"><function>cairo_surface_create_similar()</function></link>.
Alternatively, if the user passes in a reference to some backing storage
and asks cairo to wrap that in a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>, then the contents are
not modified; for example, <link linkend="cairo-image-surface-create-for-data"><function>cairo_image_surface_create_for_data()</function></link> and
<link linkend="cairo-xlib-surface-create"><function>cairo_xlib_surface_create()</function></link>.</para>
<para>Memory management of <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> is done with
<link linkend="cairo-surface-reference"><function>cairo_surface_reference()</function></link> and <link linkend="cairo-surface-destroy"><function>cairo_surface_destroy()</function></link>.</para>
<para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-content-t" role="enum" condition="since:1.0">
<title>enum cairo_content_t</title>
<indexterm zone="cairo-content-t" role="1.0"><primary sortas="content_t">cairo_content_t</primary></indexterm>
<para><link linkend="cairo-content-t"><type>cairo_content_t</type></link> is used to describe the content that a surface will
contain, whether color information, alpha information (translucence
vs. opacity), or both.</para>
<para>Note: The large values here are designed to keep <link linkend="cairo-content-t"><type>cairo_content_t</type></link>
values distinct from <link linkend="cairo-format-t"><type>cairo_format_t</type></link> values so that the
implementation can detect the error if users confuse the two types.</para>
<refsect3 id="cairo-content-t.members" role="enum_members">
<title>Members</title>
<informaltable role="enum_members_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="enum_members_name" colwidth="300px"/>
<colspec colname="enum_members_description"/>
<colspec colname="enum_members_annotations" colwidth="200px"/>
<tbody>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-CONTENT-COLOR:CAPS">CAIRO_CONTENT_COLOR</para></entry>
<entry role="enum_member_description"><para>The surface will hold color content only. (Since 1.0)</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-CONTENT-ALPHA:CAPS">CAIRO_CONTENT_ALPHA</para></entry>
<entry role="enum_member_description"><para>The surface will hold alpha content only. (Since 1.0)</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-CONTENT-COLOR-ALPHA:CAPS">CAIRO_CONTENT_COLOR_ALPHA</para></entry>
<entry role="enum_member_description"><para>The surface will hold color and alpha content. (Since 1.0)</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.0">1.0</link></para></refsect2>
<refsect2 id="cairo-surface-type-t" role="enum" condition="since:1.2">
<title>enum cairo_surface_type_t</title>
<indexterm zone="cairo-surface-type-t" role="1.2"><primary sortas="surface_type_t">cairo_surface_type_t</primary></indexterm>
<para><link linkend="cairo-surface-type-t"><type>cairo_surface_type_t</type></link> is used to describe the type of a given
surface. The surface types are also known as "backends" or "surface
backends" within cairo.</para>
<para>The type of a surface is determined by the function used to create
it, which will generally be of the form
<function>cairo_<emphasis>type</emphasis>_surface_create(<!-- -->)</function>,
(though see <link linkend="cairo-surface-create-similar"><function>cairo_surface_create_similar()</function></link> as well).</para>
<para>The surface type can be queried with <link linkend="cairo-surface-get-type"><function>cairo_surface_get_type()</function></link></para>
<para>The various <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> functions can be used with surfaces of
any type, but some backends also provide type-specific functions
that must only be called with a surface of the appropriate
type. These functions have names that begin with
<literal>cairo_<emphasis>type</emphasis>_surface</literal> such as <link linkend="cairo-image-surface-get-width"><function>cairo_image_surface_get_width()</function></link>.</para>
<para>The behavior of calling a type-specific function with a surface of
the wrong type is undefined.</para>
<para>New entries may be added in future versions.</para>
<refsect3 id="cairo-surface-type-t.members" role="enum_members">
<title>Members</title>
<informaltable role="enum_members_table" pgwide="1" frame="none">
<tgroup cols="3">
<colspec colname="enum_members_name" colwidth="300px"/>
<colspec colname="enum_members_description"/>
<colspec colname="enum_members_annotations" colwidth="200px"/>
<tbody>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-IMAGE:CAPS">CAIRO_SURFACE_TYPE_IMAGE</para></entry>
<entry role="enum_member_description"><para>The surface is of type image, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-PDF:CAPS">CAIRO_SURFACE_TYPE_PDF</para></entry>
<entry role="enum_member_description"><para>The surface is of type pdf, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-PS:CAPS">CAIRO_SURFACE_TYPE_PS</para></entry>
<entry role="enum_member_description"><para>The surface is of type ps, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-XLIB:CAPS">CAIRO_SURFACE_TYPE_XLIB</para></entry>
<entry role="enum_member_description"><para>The surface is of type xlib, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-XCB:CAPS">CAIRO_SURFACE_TYPE_XCB</para></entry>
<entry role="enum_member_description"><para>The surface is of type xcb, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-GLITZ:CAPS">CAIRO_SURFACE_TYPE_GLITZ</para></entry>
<entry role="enum_member_description"><para>The surface is of type glitz, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-QUARTZ:CAPS">CAIRO_SURFACE_TYPE_QUARTZ</para></entry>
<entry role="enum_member_description"><para>The surface is of type quartz, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-WIN32:CAPS">CAIRO_SURFACE_TYPE_WIN32</para></entry>
<entry role="enum_member_description"><para>The surface is of type win32, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-BEOS:CAPS">CAIRO_SURFACE_TYPE_BEOS</para></entry>
<entry role="enum_member_description"><para>The surface is of type beos, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-DIRECTFB:CAPS">CAIRO_SURFACE_TYPE_DIRECTFB</para></entry>
<entry role="enum_member_description"><para>The surface is of type directfb, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-SVG:CAPS">CAIRO_SURFACE_TYPE_SVG</para></entry>
<entry role="enum_member_description"><para>The surface is of type svg, since 1.2</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-OS2:CAPS">CAIRO_SURFACE_TYPE_OS2</para></entry>
<entry role="enum_member_description"><para>The surface is of type os2, since 1.4</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-WIN32-PRINTING:CAPS">CAIRO_SURFACE_TYPE_WIN32_PRINTING</para></entry>
<entry role="enum_member_description"><para>The surface is a win32 printing surface, since 1.6</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-QUARTZ-IMAGE:CAPS">CAIRO_SURFACE_TYPE_QUARTZ_IMAGE</para></entry>
<entry role="enum_member_description"><para>The surface is of type quartz_image, since 1.6</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-SCRIPT:CAPS">CAIRO_SURFACE_TYPE_SCRIPT</para></entry>
<entry role="enum_member_description"><para>The surface is of type script, since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-QT:CAPS">CAIRO_SURFACE_TYPE_QT</para></entry>
<entry role="enum_member_description"><para>The surface is of type Qt, since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-RECORDING:CAPS">CAIRO_SURFACE_TYPE_RECORDING</para></entry>
<entry role="enum_member_description"><para>The surface is of type recording, since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-VG:CAPS">CAIRO_SURFACE_TYPE_VG</para></entry>
<entry role="enum_member_description"><para>The surface is a OpenVG surface, since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-GL:CAPS">CAIRO_SURFACE_TYPE_GL</para></entry>
<entry role="enum_member_description"><para>The surface is of type OpenGL, since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-DRM:CAPS">CAIRO_SURFACE_TYPE_DRM</para></entry>
<entry role="enum_member_description"><para>The surface is of type Direct Render Manager, since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-TEE:CAPS">CAIRO_SURFACE_TYPE_TEE</para></entry>
<entry role="enum_member_description"><para>The surface is of type 'tee' (a multiplexing surface), since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-XML:CAPS">CAIRO_SURFACE_TYPE_XML</para></entry>
<entry role="enum_member_description"><para>The surface is of type XML (for debugging), since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-SKIA:CAPS">CAIRO_SURFACE_TYPE_SKIA</para></entry>
<entry /><entry />
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-SUBSURFACE:CAPS">CAIRO_SURFACE_TYPE_SUBSURFACE</para></entry>
<entry role="enum_member_description"><para>The surface is a subsurface created with
  <link linkend="cairo-surface-create-for-rectangle"><function>cairo_surface_create_for_rectangle()</function></link>, since 1.10</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
<row role="constant"><entry role="enum_member_name"><para id="CAIRO-SURFACE-TYPE-COGL:CAPS">CAIRO_SURFACE_TYPE_COGL</para></entry>
<entry role="enum_member_description"><para>This surface is of type Cogl, since 1.12</para>
</entry>
<entry role="enum_member_annotations"></entry>
</row>
</tbody></tgroup></informaltable>
</refsect3><para role="since">Since: <link linkend="api-index-1.2">1.2</link></para></refsect2>

</refsect1>
<refsect1 id="cairo-cairo-surface-t.see-also">
<title>See Also</title>
<para><link linkend="cairo-t"><type>cairo_t</type></link>, <link linkend="cairo-pattern-t"><type>cairo_pattern_t</type></link></para>

</refsect1>

</refentry>