path: root/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>

<refsynopsisdiv id="cairo-cairo-surface-t.synopsis" role="synopsis">
<title role="synopsis.title">Synopsis</title>

<synopsis>#define             <link linkend="CAIRO-MIME-TYPE-JP2:CAPS">CAIRO_MIME_TYPE_JP2</link>
#define             <link linkend="CAIRO-MIME-TYPE-JPEG:CAPS">CAIRO_MIME_TYPE_JPEG</link>
#define             <link linkend="CAIRO-MIME-TYPE-PNG:CAPS">CAIRO_MIME_TYPE_PNG</link>
#define             <link linkend="CAIRO-MIME-TYPE-URI:CAPS">CAIRO_MIME_TYPE_URI</link>
typedef             <link linkend="cairo-surface-t">cairo_surface_t</link>;
enum                <link linkend="cairo-content-t">cairo_content_t</link>;
<link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> *   <link linkend="cairo-surface-create-similar">cairo_surface_create_similar</link>        (<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>);
<link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> *   <link linkend="cairo-surface-create-for-rectangle">cairo_surface_create_for_rectangle</link>  (<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>);
<link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> *   <link linkend="cairo-surface-reference">cairo_surface_reference</link>             (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-destroy">cairo_surface_destroy</link>               (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>      <link linkend="cairo-surface-status">cairo_surface_status</link>                (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-finish">cairo_surface_finish</link>                (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-flush">cairo_surface_flush</link>                 (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="cairo-device-t"><returnvalue>cairo_device_t</returnvalue></link> *    <link linkend="cairo-surface-get-device">cairo_surface_get_device</link>            (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-get-font-options">cairo_surface_get_font_options</link>      (<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>);
<link linkend="cairo-content-t"><returnvalue>cairo_content_t</returnvalue></link>     <link linkend="cairo-surface-get-content">cairo_surface_get_content</link>           (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-mark-dirty">cairo_surface_mark_dirty</link>            (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-mark-dirty-rectangle">cairo_surface_mark_dirty_rectangle</link>  (<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>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-set-device-offset">cairo_surface_set_device_offset</link>     (<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>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-get-device-offset">cairo_surface_get_device_offset</link>     (<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>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-set-fallback-resolution">cairo_surface_set_fallback_resolution</link>
                                                        (<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>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-get-fallback-resolution">cairo_surface_get_fallback_resolution</link>
                                                        (<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>);
enum                <link linkend="cairo-surface-type-t">cairo_surface_type_t</link>;
<link linkend="cairo-surface-type-t"><returnvalue>cairo_surface_type_t</returnvalue></link>  <link linkend="cairo-surface-get-type">cairo_surface_get_type</link>            (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
unsigned <link linkend="int"><returnvalue>int</returnvalue></link>        <link linkend="cairo-surface-get-reference-count">cairo_surface_get_reference_count</link>   (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>      <link linkend="cairo-surface-set-user-data">cairo_surface_set_user_data</link>         (<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>);
<link linkend="void"><returnvalue>void</returnvalue></link> *              <link linkend="cairo-surface-get-user-data">cairo_surface_get_user_data</link>         (<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>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-copy-page">cairo_surface_copy_page</link>             (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-show-page">cairo_surface_show_page</link>             (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="cairo-bool-t"><returnvalue>cairo_bool_t</returnvalue></link>        <link linkend="cairo-surface-has-show-text-glyphs">cairo_surface_has_show_text_glyphs</link>  (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>);
<link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link>      <link linkend="cairo-surface-set-mime-data">cairo_surface_set_mime_data</link>         (<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>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>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-surface-get-mime-data">cairo_surface_get_mime_data</link>         (<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>unsigned <link linkend="char"><type>char</type></link> **data</parameter>,
                                                         <parameter>unsigned <link linkend="long"><type>long</type></link> *length</parameter>);
</synopsis>
</refsynopsisdiv>

<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
cairo_<emphasis>backend</emphasis><link linkend="surface-create"><function>_surface_create()</function></link>.
</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.
<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>
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.details" role="details">
<title role="details.title">Details</title>
<refsect2 id="CAIRO-MIME-TYPE-JP2:CAPS" role="macro">
<title>CAIRO_MIME_TYPE_JP2</title>
<indexterm zone="CAIRO-MIME-TYPE-JP2:CAPS"><primary sortas="MIME_TYPE_JP2">CAIRO_MIME_TYPE_JP2</primary></indexterm>
<programlisting>#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>
<parameter>Since</parameter>: 1.10
</para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-JPEG:CAPS" role="macro">
<title>CAIRO_MIME_TYPE_JPEG</title>
<indexterm zone="CAIRO-MIME-TYPE-JPEG:CAPS"><primary sortas="MIME_TYPE_JPEG">CAIRO_MIME_TYPE_JPEG</primary></indexterm>
<programlisting>#define CAIRO_MIME_TYPE_JPEG "image/jpeg"
</programlisting>
<para>
The Joint Photographic Experts Group (JPEG) image coding standard (ISO/IEC 10918-1).
</para>
<para>
<parameter>Since</parameter>: 1.10
</para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-PNG:CAPS" role="macro">
<title>CAIRO_MIME_TYPE_PNG</title>
<indexterm zone="CAIRO-MIME-TYPE-PNG:CAPS"><primary sortas="MIME_TYPE_PNG">CAIRO_MIME_TYPE_PNG</primary></indexterm>
<programlisting>#define CAIRO_MIME_TYPE_PNG "image/png"
</programlisting>
<para>
The Portable Network Graphics image file format (ISO/IEC 15948).
</para>
<para>
<parameter>Since</parameter>: 1.10
</para></refsect2>
<refsect2 id="CAIRO-MIME-TYPE-URI:CAPS" role="macro">
<title>CAIRO_MIME_TYPE_URI</title>
<indexterm zone="CAIRO-MIME-TYPE-URI:CAPS"><primary sortas="MIME_TYPE_URI">CAIRO_MIME_TYPE_URI</primary></indexterm>
<programlisting>#define CAIRO_MIME_TYPE_URI "text/x-uri"
</programlisting>
<para>
URI for an image file (unofficial MIME type).
</para>
<para>
<parameter>Since</parameter>: 1.10
</para></refsect2>
<refsect2 id="cairo-surface-t" role="typedef">
<title>cairo_surface_t</title>
<indexterm zone="cairo-surface-t"><primary sortas="surface_t">cairo_surface_t</primary></indexterm>
<programlisting>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></refsect2>
<refsect2 id="cairo-content-t" role="enum">
<title>enum cairo_content_t</title>
<indexterm zone="cairo-content-t"><primary sortas="content_t">cairo_content_t</primary></indexterm>
<programlisting>typedef enum _cairo_content {
    CAIRO_CONTENT_COLOR		= 0x1000,
    CAIRO_CONTENT_ALPHA		= 0x2000,
    CAIRO_CONTENT_COLOR_ALPHA&#160;= 0x3000
} cairo_content_t;
</programlisting>
<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><variablelist role="enum">
<varlistentry id="CAIRO-CONTENT-COLOR:CAPS" role="constant">
<term><literal>CAIRO_CONTENT_COLOR</literal></term>
<listitem><simpara>The surface will hold color content only.
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-CONTENT-ALPHA:CAPS" role="constant">
<term><literal>CAIRO_CONTENT_ALPHA</literal></term>
<listitem><simpara>The surface will hold alpha content only.
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-CONTENT-COLOR-ALPHA:CAPS" role="constant">
<term><literal>CAIRO_CONTENT_COLOR_ALPHA</literal></term>
<listitem><simpara>The surface will hold color and alpha content.
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-create-similar" role="function">
<title>cairo_surface_create_similar ()</title>
<indexterm zone="cairo-surface-create-similar"><primary sortas="surface_create_similar">cairo_surface_create_similar</primary></indexterm>
<programlisting><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> *   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
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><variablelist role="params">
<varlistentry><term><parameter>other</parameter>&#160;:</term>
<listitem><simpara>an existing surface used to select the backend of the new surface
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>content</parameter>&#160;:</term>
<listitem><simpara>the content for the new surface
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>width</parameter>&#160;:</term>
<listitem><simpara>width of the new surface, (in device-space units)
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>height</parameter>&#160;:</term>
<listitem><simpara>height of the new surface (in device-space units)
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> 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.

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.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-create-for-rectangle" role="function" condition="since:1.10">
<title>cairo_surface_create_for_rectangle ()</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><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> *   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>
<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>
</para><variablelist role="params">
<varlistentry><term><parameter>target</parameter>&#160;:</term>
<listitem><simpara>an existing surface for which the sub-surface will point to
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x</parameter>&#160;:</term>
<listitem><simpara>the x-origin of the sub-surface from the top-left of the target surface (in device-space units)
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y</parameter>&#160;:</term>
<listitem><simpara>the y-origin of the sub-surface from the top-left of the target surface (in device-space units)
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>width</parameter>&#160;:</term>
<listitem><simpara>width of the sub-surface (in device-space units)
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>height</parameter>&#160;:</term>
<listitem><simpara>height of the sub-surface (in device-space units)
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> 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.

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.

</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.10</para></refsect2>
<refsect2 id="cairo-surface-reference" role="function">
<title>cairo_surface_reference ()</title>
<indexterm zone="cairo-surface-reference"><primary sortas="surface_reference">cairo_surface_reference</primary></indexterm>
<programlisting><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> *   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>
The number of references to a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> can be get using
<link linkend="cairo-surface-get-reference-count"><function>cairo_surface_get_reference_count()</function></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> the referenced <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-destroy" role="function">
<title>cairo_surface_destroy ()</title>
<indexterm zone="cairo-surface-destroy"><primary sortas="surface_destroy">cairo_surface_destroy</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-status" role="function">
<title>cairo_surface_status ()</title>
<indexterm zone="cairo-surface-status"><primary sortas="surface_status">cairo_surface_status</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> <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>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-finish" role="function">
<title>cairo_surface_finish ()</title>
<indexterm zone="cairo-surface-finish"><primary sortas="surface_finish">cairo_surface_finish</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>the <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> to finish
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-flush" role="function">
<title>cairo_surface_flush ()</title>
<indexterm zone="cairo-surface-flush"><primary sortas="surface_flush">cairo_surface_flush</primary></indexterm>
<programlisting><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. If the surface doesn't support direct access,
then this function does nothing.
</para><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-get-device" role="function" condition="since:1.10">
<title>cairo_surface_get_device ()</title>
<indexterm zone="cairo-surface-get-device" role="1.10"><primary sortas="surface_get_device">cairo_surface_get_device</primary></indexterm>
<programlisting><link linkend="cairo-device-t"><returnvalue>cairo_device_t</returnvalue></link> *    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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> The device for <parameter>surface</parameter> or <link linkend="NULL:CAPS"><literal>NULL</literal></link> if the surface does
              not have an associated device.

</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.10</para></refsect2>
<refsect2 id="cairo-surface-get-font-options" role="function">
<title>cairo_surface_get_font_options ()</title>
<indexterm zone="cairo-surface-get-font-options"><primary sortas="surface_get_font_options">cairo_surface_get_font_options</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>options</parameter>&#160;:</term>
<listitem><simpara>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
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-get-content" role="function" condition="since:1.2">
<title>cairo_surface_get_content ()</title>
<indexterm zone="cairo-surface-get-content" role="1.2"><primary sortas="surface_get_content">cairo_surface_get_content</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> The content type of <parameter>surface</parameter>.

</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-surface-mark-dirty" role="function">
<title>cairo_surface_mark_dirty ()</title>
<indexterm zone="cairo-surface-mark-dirty"><primary sortas="surface_mark_dirty">cairo_surface_mark_dirty</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-mark-dirty-rectangle" role="function">
<title>cairo_surface_mark_dirty_rectangle ()</title>
<indexterm zone="cairo-surface-mark-dirty-rectangle"><primary sortas="surface_mark_dirty_rectangle">cairo_surface_mark_dirty_rectangle</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x</parameter>&#160;:</term>
<listitem><simpara>X coordinate of dirty rectangle
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y</parameter>&#160;:</term>
<listitem><simpara>Y coordinate of dirty rectangle
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>width</parameter>&#160;:</term>
<listitem><simpara>width of dirty rectangle
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>height</parameter>&#160;:</term>
<listitem><simpara>height of dirty rectangle
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-set-device-offset" role="function">
<title>cairo_surface_set_device_offset ()</title>
<indexterm zone="cairo-surface-set-device-offset"><primary sortas="surface_set_device_offset">cairo_surface_set_device_offset</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x_offset</parameter>&#160;:</term>
<listitem><simpara>the offset in the X direction, in device units
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y_offset</parameter>&#160;:</term>
<listitem><simpara>the offset in the Y direction, in device units
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-get-device-offset" role="function" condition="since:1.2">
<title>cairo_surface_get_device_offset ()</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><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x_offset</parameter>&#160;:</term>
<listitem><simpara>the offset in the X direction, in device units
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y_offset</parameter>&#160;:</term>
<listitem><simpara>the offset in the Y direction, in device units
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-surface-set-fallback-resolution" role="function" condition="since:1.2">
<title>cairo_surface_set_fallback_resolution ()</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><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x_pixels_per_inch</parameter>&#160;:</term>
<listitem><simpara>horizontal setting for pixels per inch
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y_pixels_per_inch</parameter>&#160;:</term>
<listitem><simpara>vertical setting for pixels per inch
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-surface-get-fallback-resolution" role="function" condition="since:1.8">
<title>cairo_surface_get_fallback_resolution ()</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><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x_pixels_per_inch</parameter>&#160;:</term>
<listitem><simpara>horizontal pixels per inch
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y_pixels_per_inch</parameter>&#160;:</term>
<listitem><simpara>vertical pixels per inch
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</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>
<programlisting>typedef enum _cairo_surface_type {
    CAIRO_SURFACE_TYPE_IMAGE,
    CAIRO_SURFACE_TYPE_PDF,
    CAIRO_SURFACE_TYPE_PS,
    CAIRO_SURFACE_TYPE_XLIB,
    CAIRO_SURFACE_TYPE_XCB,
    CAIRO_SURFACE_TYPE_GLITZ,
    CAIRO_SURFACE_TYPE_QUARTZ,
    CAIRO_SURFACE_TYPE_WIN32,
    CAIRO_SURFACE_TYPE_BEOS,
    CAIRO_SURFACE_TYPE_DIRECTFB,
    CAIRO_SURFACE_TYPE_SVG,
    CAIRO_SURFACE_TYPE_OS2,
    CAIRO_SURFACE_TYPE_WIN32_PRINTING,
    CAIRO_SURFACE_TYPE_QUARTZ_IMAGE,
    CAIRO_SURFACE_TYPE_SCRIPT,
    CAIRO_SURFACE_TYPE_QT,
    CAIRO_SURFACE_TYPE_RECORDING,
    CAIRO_SURFACE_TYPE_VG,
    CAIRO_SURFACE_TYPE_GL,
    CAIRO_SURFACE_TYPE_DRM,
    CAIRO_SURFACE_TYPE_TEE,
    CAIRO_SURFACE_TYPE_XML,
    CAIRO_SURFACE_TYPE_SKIA,
    CAIRO_SURFACE_TYPE_SUBSURFACE
} cairo_surface_type_t;
</programlisting>
<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 cairo_<emphasis>type</emphasis><link linkend="surface-create"><function>_surface_create()</function></link>,
(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
cairo_<emphasis>type</emphasis>_surface<!-- --> 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><variablelist role="enum">
<varlistentry id="CAIRO-SURFACE-TYPE-IMAGE:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_IMAGE</literal></term>
<listitem><simpara>The surface is of type image
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-PDF:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_PDF</literal></term>
<listitem><simpara>The surface is of type pdf
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-PS:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_PS</literal></term>
<listitem><simpara>The surface is of type ps
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-XLIB:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_XLIB</literal></term>
<listitem><simpara>The surface is of type xlib
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-XCB:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_XCB</literal></term>
<listitem><simpara>The surface is of type xcb
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-GLITZ:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_GLITZ</literal></term>
<listitem><simpara>The surface is of type glitz
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-QUARTZ:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_QUARTZ</literal></term>
<listitem><simpara>The surface is of type quartz
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-WIN32:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_WIN32</literal></term>
<listitem><simpara>The surface is of type win32
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-BEOS:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_BEOS</literal></term>
<listitem><simpara>The surface is of type beos
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-DIRECTFB:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_DIRECTFB</literal></term>
<listitem><simpara>The surface is of type directfb
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-SVG:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_SVG</literal></term>
<listitem><simpara>The surface is of type svg
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-OS2:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_OS2</literal></term>
<listitem><simpara>The surface is of type os2
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-WIN32-PRINTING:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_WIN32_PRINTING</literal></term>
<listitem><simpara>The surface is a win32 printing surface
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-QUARTZ-IMAGE:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_QUARTZ_IMAGE</literal></term>
<listitem><simpara>The surface is of type quartz_image
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-SCRIPT:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_SCRIPT</literal></term>
<listitem><simpara>The surface is of type script, since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-QT:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_QT</literal></term>
<listitem><simpara>The surface is of type Qt, since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-RECORDING:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_RECORDING</literal></term>
<listitem><simpara>The surface is of type recording, since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-VG:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_VG</literal></term>
<listitem><simpara>The surface is a OpenVG surface, since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-GL:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_GL</literal></term>
<listitem><simpara>The surface is of type OpenGL, since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-DRM:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_DRM</literal></term>
<listitem><simpara>The surface is of type Direct Render Manager, since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-TEE:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_TEE</literal></term>
<listitem><simpara>The surface is of type 'tee' (a multiplexing surface), since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-XML:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_XML</literal></term>
<listitem><simpara>The surface is of type XML (for debugging), since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-SKIA:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_SKIA</literal></term>
<listitem><simpara>The surface is of type Skia, since 1.10
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-SURFACE-TYPE-SUBSURFACE:CAPS" role="constant">
<term><literal>CAIRO_SURFACE_TYPE_SUBSURFACE</literal></term>
<listitem><simpara>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
</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-surface-get-type" role="function" condition="since:1.2">
<title>cairo_surface_get_type ()</title>
<indexterm zone="cairo-surface-get-type" role="1.2"><primary sortas="surface_get_type">cairo_surface_get_type</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> The type of <parameter>surface</parameter>.

</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-surface-get-reference-count" role="function" condition="since:1.4">
<title>cairo_surface_get_reference_count ()</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>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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> the current reference count of <parameter>surface</parameter>.  If the
object is a nil object, 0 will be returned.

</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.4</para></refsect2>
<refsect2 id="cairo-surface-set-user-data" role="function">
<title>cairo_surface_set_user_data ()</title>
<indexterm zone="cairo-surface-set-user-data"><primary sortas="surface_set_user_data">cairo_surface_set_user_data</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>key</parameter>&#160;:</term>
<listitem><simpara>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
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>user_data</parameter>&#160;:</term>
<listitem><simpara>the user data to attach to the surface
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>destroy</parameter>&#160;:</term>
<listitem><simpara>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.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> <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.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-get-user-data" role="function">
<title>cairo_surface_get_user_data ()</title>
<indexterm zone="cairo-surface-get-user-data"><primary sortas="surface_get_user_data">cairo_surface_get_user_data</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> *              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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>key</parameter>&#160;:</term>
<listitem><simpara>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
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> the user data previously attached or <link linkend="NULL:CAPS"><literal>NULL</literal></link>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-surface-copy-page" role="function" condition="since:1.6">
<title>cairo_surface_copy_page ()</title>
<indexterm zone="cairo-surface-copy-page" role="1.6"><primary sortas="surface_copy_page">cairo_surface_copy_page</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.6</para></refsect2>
<refsect2 id="cairo-surface-show-page" role="function" condition="since:1.6">
<title>cairo_surface_show_page ()</title>
<indexterm zone="cairo-surface-show-page" role="1.6"><primary sortas="surface_show_page">cairo_surface_show_page</primary></indexterm>
<programlisting><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-Surface-t"><type>cairo_Surface_t</type></link>
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.6</para></refsect2>
<refsect2 id="cairo-surface-has-show-text-glyphs" role="function" condition="since:1.8">
<title>cairo_surface_has_show_text_glyphs ()</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><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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> <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

</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-surface-set-mime-data" role="function" condition="since:1.10">
<title>cairo_surface_set_mime_data ()</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><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>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>.
</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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>mime_type</parameter>&#160;:</term>
<listitem><simpara>the MIME type of the image data
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>data</parameter>&#160;:</term>
<listitem><simpara>the image data to attach to the surface
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>length</parameter>&#160;:</term>
<listitem><simpara>the length of the image data
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>destroy</parameter>&#160;:</term>
<listitem><simpara>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.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>closure</parameter>&#160;:</term>
<listitem><simpara>the data to be passed to the <parameter>destroy</parameter> notifier
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara> <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.
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.10</para></refsect2>
<refsect2 id="cairo-surface-get-mime-data" role="function" condition="since:1.10">
<title>cairo_surface_get_mime_data ()</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><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>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><variablelist role="params">
<varlistentry><term><parameter>surface</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>mime_type</parameter>&#160;:</term>
<listitem><simpara>the mime type of the image data
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>data</parameter>&#160;:</term>
<listitem><simpara>the image data to attached to the surface
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>length</parameter>&#160;:</term>
<listitem><simpara>the length of the image data
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.10</para></refsect2>

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

</refentry>