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<refentry id="cairo-cairo-t">
<refmeta>
<refentrytitle role="top_of_page">cairo_t</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>CAIRO Library</refmiscinfo>
</refmeta>

<refnamediv>
<refname>cairo_t</refname>
<refpurpose>The cairo drawing context</refpurpose>
<!--[<xref linkend="desc" endterm="desc.title"/>]-->
</refnamediv>

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

<synopsis>



typedef     <link linkend="cairo-t">cairo_t</link>;
<link linkend="cairo-t">cairo_t</link>*    <link linkend="cairo-create">cairo_create</link>                    (<link linkend="cairo-surface-t">cairo_surface_t</link> *target);
<link linkend="cairo-t">cairo_t</link>*    <link linkend="cairo-reference">cairo_reference</link>                 (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-destroy">cairo_destroy</link>                   (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="cairo-status-t">cairo_status_t</link> <link linkend="cairo-status">cairo_status</link>                 (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-save">cairo_save</link>                      (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-restore">cairo_restore</link>                   (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="cairo-surface-t">cairo_surface_t</link>* <link linkend="cairo-get-target">cairo_get_target</link>           (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-push-group">cairo_push_group</link>                (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-push-group-with-content">cairo_push_group_with_content</link>   (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-content-t">cairo_content_t</link> content);
<link linkend="cairo-pattern-t">cairo_pattern_t</link>* <link linkend="cairo-pop-group">cairo_pop_group</link>            (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-pop-group-to-source">cairo_pop_group_to_source</link>       (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="cairo-surface-t">cairo_surface_t</link>* <link linkend="cairo-get-group-target">cairo_get_group_target</link>     (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-set-source-rgb">cairo_set_source_rgb</link>            (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> red,
                                             <link linkend="double">double</link> green,
                                             <link linkend="double">double</link> blue);
<link linkend="void">void</link>        <link linkend="cairo-set-source-rgba">cairo_set_source_rgba</link>           (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> red,
                                             <link linkend="double">double</link> green,
                                             <link linkend="double">double</link> blue,
                                             <link linkend="double">double</link> alpha);
<link linkend="void">void</link>        <link linkend="cairo-set-source">cairo_set_source</link>                (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-pattern-t">cairo_pattern_t</link> *source);
<link linkend="void">void</link>        <link linkend="cairo-set-source-surface">cairo_set_source_surface</link>        (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-surface-t">cairo_surface_t</link> *surface,
                                             <link linkend="double">double</link> x,
                                             <link linkend="double">double</link> y);
<link linkend="cairo-pattern-t">cairo_pattern_t</link>* <link linkend="cairo-get-source">cairo_get_source</link>           (<link linkend="cairo-t">cairo_t</link> *cr);
enum        <link linkend="cairo-antialias-t">cairo_antialias_t</link>;
<link linkend="void">void</link>        <link linkend="cairo-set-antialias">cairo_set_antialias</link>             (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-antialias-t">cairo_antialias_t</link> antialias);
<link linkend="cairo-antialias-t">cairo_antialias_t</link> <link linkend="cairo-get-antialias">cairo_get_antialias</link>       (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-set-dash">cairo_set_dash</link>                  (<link linkend="cairo-t">cairo_t</link> *cr,
                                             const <link linkend="double">double</link> *dashes,
                                             <link linkend="int">int</link> num_dashes,
                                             <link linkend="double">double</link> offset);
enum        <link linkend="cairo-fill-rule-t">cairo_fill_rule_t</link>;
<link linkend="void">void</link>        <link linkend="cairo-set-fill-rule">cairo_set_fill_rule</link>             (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-fill-rule-t">cairo_fill_rule_t</link> fill_rule);
<link linkend="cairo-fill-rule-t">cairo_fill_rule_t</link> <link linkend="cairo-get-fill-rule">cairo_get_fill_rule</link>       (<link linkend="cairo-t">cairo_t</link> *cr);
enum        <link linkend="cairo-line-cap-t">cairo_line_cap_t</link>;
<link linkend="void">void</link>        <link linkend="cairo-set-line-cap">cairo_set_line_cap</link>              (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-line-cap-t">cairo_line_cap_t</link> line_cap);
<link linkend="cairo-line-cap-t">cairo_line_cap_t</link> <link linkend="cairo-get-line-cap">cairo_get_line_cap</link>         (<link linkend="cairo-t">cairo_t</link> *cr);
enum        <link linkend="cairo-line-join-t">cairo_line_join_t</link>;
<link linkend="void">void</link>        <link linkend="cairo-set-line-join">cairo_set_line_join</link>             (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-line-join-t">cairo_line_join_t</link> line_join);
<link linkend="cairo-line-join-t">cairo_line_join_t</link> <link linkend="cairo-get-line-join">cairo_get_line_join</link>       (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-set-line-width">cairo_set_line_width</link>            (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> width);
<link linkend="double">double</link>      <link linkend="cairo-get-line-width">cairo_get_line_width</link>            (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-set-miter-limit">cairo_set_miter_limit</link>           (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> limit);
<link linkend="double">double</link>      <link linkend="cairo-get-miter-limit">cairo_get_miter_limit</link>           (<link linkend="cairo-t">cairo_t</link> *cr);
enum        <link linkend="cairo-operator-t">cairo_operator_t</link>;
<link linkend="void">void</link>        <link linkend="cairo-set-operator">cairo_set_operator</link>              (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-operator-t">cairo_operator_t</link> op);
<link linkend="cairo-operator-t">cairo_operator_t</link> <link linkend="cairo-get-operator">cairo_get_operator</link>         (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-set-tolerance">cairo_set_tolerance</link>             (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> tolerance);
<link linkend="double">double</link>      <link linkend="cairo-get-tolerance">cairo_get_tolerance</link>             (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-clip">cairo_clip</link>                      (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-clip-preserve">cairo_clip_preserve</link>             (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-reset-clip">cairo_reset_clip</link>                (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-fill">cairo_fill</link>                      (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-fill-preserve">cairo_fill_preserve</link>             (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-fill-extents">cairo_fill_extents</link>              (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> *x1,
                                             <link linkend="double">double</link> *y1,
                                             <link linkend="double">double</link> *x2,
                                             <link linkend="double">double</link> *y2);
<link linkend="cairo-bool-t">cairo_bool_t</link> <link linkend="cairo-in-fill">cairo_in_fill</link>                  (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> x,
                                             <link linkend="double">double</link> y);
<link linkend="void">void</link>        <link linkend="cairo-mask">cairo_mask</link>                      (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-pattern-t">cairo_pattern_t</link> *pattern);
<link linkend="void">void</link>        <link linkend="cairo-mask-surface">cairo_mask_surface</link>              (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-surface-t">cairo_surface_t</link> *surface,
                                             <link linkend="double">double</link> surface_x,
                                             <link linkend="double">double</link> surface_y);
<link linkend="void">void</link>        <link linkend="cairo-paint">cairo_paint</link>                     (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-paint-with-alpha">cairo_paint_with_alpha</link>          (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> alpha);
<link linkend="void">void</link>        <link linkend="cairo-stroke">cairo_stroke</link>                    (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-stroke-preserve">cairo_stroke_preserve</link>           (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-stroke-extents">cairo_stroke_extents</link>            (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> *x1,
                                             <link linkend="double">double</link> *y1,
                                             <link linkend="double">double</link> *x2,
                                             <link linkend="double">double</link> *y2);
<link linkend="cairo-bool-t">cairo_bool_t</link> <link linkend="cairo-in-stroke">cairo_in_stroke</link>                (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> x,
                                             <link linkend="double">double</link> y);
<link linkend="void">void</link>        <link linkend="cairo-copy-page">cairo_copy_page</link>                 (<link linkend="cairo-t">cairo_t</link> *cr);
<link linkend="void">void</link>        <link linkend="cairo-show-page">cairo_show_page</link>                 (<link linkend="cairo-t">cairo_t</link> *cr);

</synopsis>
</refsynopsisdiv>









<refsect1 role="desc">
<title role="desc.title">Description</title>

  <para>
    <link linkend="cairo-t"><type>cairo_t</type></link> is the main object used when drawing with cairo. To
    draw with cairo, you create a <link linkend="cairo-t"><type>cairo_t</type></link>, set the target surface,
    and drawing options for the <link linkend="cairo-t"><type>cairo_t</type></link>, create shapes with
    functions like <link linkend="cairo-move-to"><function>cairo_move_to()</function></link> and <link linkend="cairo-line-to"><function>cairo_line_to()</function></link>, and then
    draw shapes with <link linkend="cairo-stroke"><function>cairo_stroke()</function></link> or <link linkend="cairo-fill"><function>cairo_fill()</function></link>.
  </para>
  <para>
    <link linkend="cairo-t"><type>cairo_t</type></link><!-- -->'s can be pushed to a stack via <link linkend="cairo-save"><function>cairo_save()</function></link>.
    They may then safely be changed, without loosing the current state.
    Use <link linkend="cairo-restore"><function>cairo_restore()</function></link> to restore to the saved state.
  </para>
</refsect1>

<refsect1 role="details">
<title role="details.title">Details</title>
<refsect2>
<title><anchor id="cairo-t" role="typedef"/>cairo_t</title>
<indexterm><primary>cairo_t</primary></indexterm><programlisting>typedef struct _cairo cairo_t;
</programlisting>
<para>
A <link linkend="cairo-t"><type>cairo_t</type></link> contains the current state of the rendering device,
including coordinates of yet to be drawn shapes.</para>
<para>

</para></refsect2>
<refsect2>
<title><anchor id="cairo-create" role="function"/>cairo_create ()</title>
<indexterm><primary>cairo_create</primary></indexterm><programlisting><link linkend="cairo-t">cairo_t</link>*    cairo_create                    (<link linkend="cairo-surface-t">cairo_surface_t</link> *target);</programlisting>
<para>
Creates a new <link linkend="cairo-t"><type>cairo_t</type></link> with all graphics state parameters set to
default values and with <parameter>target</parameter> as a target surface. The target
surface should be constructed with a backend-specific function such
as <link linkend="cairo-image-surface-create"><function>cairo_image_surface_create()</function></link> (or any other
<literal>cairo_&lt;backend&gt;_surface_create</literal> variant).
</para>
<para>
This function references <parameter>target</parameter>, so you can immediately
call <link linkend="cairo-surface-destroy"><function>cairo_surface_destroy()</function></link> on it if you don't need to
maintain a separate reference to it.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>target</parameter>&nbsp;:</term>
<listitem><simpara> target surface for the context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> a newly allocated <link linkend="cairo-t"><type>cairo_t</type></link> with a reference
 count of 1. The initial reference count should be released
 with <link linkend="cairo-destroy"><function>cairo_destroy()</function></link> when you are done using the <link linkend="cairo-t"><type>cairo_t</type></link>.
 This function never returns <link linkend="NULL:CAPS"><literal>NULL</literal></link>. If memory cannot be
 allocated, a special <link linkend="cairo-t"><type>cairo_t</type></link> object will be returned on
 which <link linkend="cairo-status"><function>cairo_status()</function></link> returns <link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link>.
 You can use this object normally, but no drawing will
 be done.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-reference" role="function"/>cairo_reference ()</title>
<indexterm><primary>cairo_reference</primary></indexterm><programlisting><link linkend="cairo-t">cairo_t</link>*    cairo_reference                 (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Increases the reference count on <parameter>cr</parameter> by one. This prevents
<parameter>cr</parameter> from being destroyed until a matching call to <link linkend="cairo-destroy"><function>cairo_destroy()</function></link>
is made.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the referenced <link linkend="cairo-t"><type>cairo_t</type></link>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-destroy" role="function"/>cairo_destroy ()</title>
<indexterm><primary>cairo_destroy</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_destroy                   (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Decreases the reference count on <parameter>cr</parameter> by one. If the result
is zero, then <parameter>cr</parameter> and all associated resources are freed.
See <link linkend="cairo-reference"><function>cairo_reference()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-status" role="function"/>cairo_status ()</title>
<indexterm><primary>cairo_status</primary></indexterm><programlisting><link linkend="cairo-status-t">cairo_status_t</link> cairo_status                 (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Checks whether an error has previously occurred for this context.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara>the current status of this context, see <link linkend="cairo-status-t"><type>cairo_status_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-save" role="function"/>cairo_save ()</title>
<indexterm><primary>cairo_save</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_save                      (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Makes a copy of the current state of <parameter>cr</parameter> and saves it
on an internal stack of saved states for <parameter>cr</parameter>. When
<link linkend="cairo-restore"><function>cairo_restore()</function></link> is called, <parameter>cr</parameter> will be restored to
the saved state. Multiple calls to <link linkend="cairo-save"><function>cairo_save()</function></link> and
<link linkend="cairo-restore"><function>cairo_restore()</function></link> can be nested; each call to <link linkend="cairo-restore"><function>cairo_restore()</function></link>
restores the state from the matching paired <link linkend="cairo-save"><function>cairo_save()</function></link>.
</para>
<para>
It isn't necessary to clear all saved states before
a <link linkend="cairo-t"><type>cairo_t</type></link> is freed. If the reference count of a <link linkend="cairo-t"><type>cairo_t</type></link>
drops to zero in response to a call to <link linkend="cairo-destroy"><function>cairo_destroy()</function></link>,
any saved states will be freed along with the <link linkend="cairo-t"><type>cairo_t</type></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-restore" role="function"/>cairo_restore ()</title>
<indexterm><primary>cairo_restore</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_restore                   (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Restores <parameter>cr</parameter> to the state saved by a preceding call to
<link linkend="cairo-save"><function>cairo_save()</function></link> and removes that state from the stack of
saved states.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-target" role="function"/>cairo_get_target ()</title>
<indexterm><primary>cairo_get_target</primary></indexterm><programlisting><link linkend="cairo-surface-t">cairo_surface_t</link>* cairo_get_target           (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the target surface for the cairo context as passed to
<link linkend="cairo-create"><function>cairo_create()</function></link>.
</para>
<para>
This function will always return a valid pointer, but the result
can be a "nil" surface if <parameter>cr</parameter> is already in an error state,
(ie. <link linkend="cairo-status"><function>cairo_status()</function></link> <literal>!=</literal> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link>).
A nil surface is indicated by <link linkend="cairo-surface-status"><function>cairo_surface_status()</function></link>
<literal>!=</literal> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the target surface. This object is owned by cairo. To
keep a reference to it, you must call <link linkend="cairo-surface-reference"><function>cairo_surface_reference()</function></link>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-push-group" role="function" condition="since:1.2"/>cairo_push_group ()</title>
<indexterm role="1.2"><primary>cairo_push_group</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_push_group                (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Temporarily redirects drawing to an intermediate surface known as a
group. The redirection lasts until the group is completed by a call
to <link linkend="cairo-pop-group"><function>cairo_pop_group()</function></link> or <link linkend="cairo-pop-group-to-source"><function>cairo_pop_group_to_source()</function></link>. These calls
provide the result of any drawing to the group as a pattern,
(either as an explicit object, or set as the source pattern).
</para>
<para>
This group functionality can be convenient for performing
intermediate compositing. One common use of a group is to render
objects as opaque within the group, (so that they occlude each
other), and then blend the result with translucence onto the
destination.
</para>
<para>
Groups can be nested arbitrarily deep by making balanced calls to
<link linkend="cairo-push-group"><function>cairo_push_group()</function></link>/<link linkend="cairo-pop-group"><function>cairo_pop_group()</function></link>. Each call pushes/pops the new
target group onto/from a stack.
</para>
<para>
The <link linkend="cairo-push-group"><function>cairo_push_group()</function></link> function calls <link linkend="cairo-save"><function>cairo_save()</function></link> so that any
changes to the graphics state will not be visible outside the
group, (the pop_group functions call <link linkend="cairo-restore"><function>cairo_restore()</function></link>).
</para>
<para>
By default the intermediate group will have a content type of
CAIRO_CONTENT_COLOR_ALPHA. Other content types can be chosen for
the group by using <link linkend="cairo-push-group-with-content"><function>cairo_push_group_with_content()</function></link> instead.
</para>
<para>
As an example, here is how one might fill and stroke a path with
translucence, but without any portion of the fill being visible
under the stroke:
</para>
<para>
<informalexample><programlisting>
cairo_push_group (cr);
cairo_set_source (cr, fill_pattern);
cairo_fill_preserve (cr);
cairo_set_source (cr, stroke_pattern);
cairo_stroke (cr);
cairo_pop_group_to_source (cr);
cairo_paint_with_alpha (cr, alpha);
</programlisting></informalexample></para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist><para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-push-group-with-content" role="function" condition="since:1.2"/>cairo_push_group_with_content ()</title>
<indexterm role="1.2"><primary>cairo_push_group_with_content</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_push_group_with_content   (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-content-t">cairo_content_t</link> content);</programlisting>
<para>
Temporarily redirects drawing to an intermediate surface known as a
group. The redirection lasts until the group is completed by a call
to <link linkend="cairo-pop-group"><function>cairo_pop_group()</function></link> or <link linkend="cairo-pop-group-to-source"><function>cairo_pop_group_to_source()</function></link>. These calls
provide the result of any drawing to the group as a pattern,
(either as an explicit object, or set as the source pattern).
</para>
<para>
The group will have a content type of <parameter>content</parameter>. The ability to
control this content type is the only distinction between this
function and <link linkend="cairo-push-group"><function>cairo_push_group()</function></link> which you should see for a more
detailed description of group rendering.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>content</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-content-t"><literal>cairo_content_t</literal></link> indicating the type of group that
          will be created
</simpara></listitem></varlistentry>
</variablelist><para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-pop-group" role="function" condition="since:1.2"/>cairo_pop_group ()</title>
<indexterm role="1.2"><primary>cairo_pop_group</primary></indexterm><programlisting><link linkend="cairo-pattern-t">cairo_pattern_t</link>* cairo_pop_group            (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Terminates the redirection begun by a call to <link linkend="cairo-push-group"><function>cairo_push_group()</function></link> or
<link linkend="cairo-push-group-with-content"><function>cairo_push_group_with_content()</function></link> and returns a new pattern
containing the results of all drawing operations performed to the
group.
</para>
<para>
The <link linkend="cairo-pop-group"><function>cairo_pop_group()</function></link> function calls <link linkend="cairo-restore"><function>cairo_restore()</function></link>, (balancing a
call to <link linkend="cairo-save"><function>cairo_save()</function></link> by the push_group function), so that any
changes to the graphics state will not be visible outside the
group.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> a newly created (surface) pattern containing the
results of all drawing operations performed to the group. The
caller owns the returned object and should call
<link linkend="cairo-pattern-destroy"><function>cairo_pattern_destroy()</function></link> when finished with it.

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-pop-group-to-source" role="function" condition="since:1.2"/>cairo_pop_group_to_source ()</title>
<indexterm role="1.2"><primary>cairo_pop_group_to_source</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_pop_group_to_source       (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Terminates the redirection begun by a call to <link linkend="cairo-push-group"><function>cairo_push_group()</function></link> or
<link linkend="cairo-push-group-with-content"><function>cairo_push_group_with_content()</function></link> and installs the resulting pattern
as the source pattern in the given cairo context.
</para>
<para>
The behavior of this function is equivalent to the sequence of
operations:
</para>
<para>
<informalexample><programlisting>
cairo_pattern_t *group = cairo_pop_group (cr);
cairo_set_source (cr, group);
cairo_pattern_destroy (group);
</programlisting></informalexample>
</para>
<para>
but is more convenient as their is no need for a variable to store
the short-lived pointer to the pattern.
</para>
<para>
The <link linkend="cairo-pop-group"><function>cairo_pop_group()</function></link> function calls <link linkend="cairo-restore"><function>cairo_restore()</function></link>, (balancing a
call to <link linkend="cairo-save"><function>cairo_save()</function></link> by the push_group function), so that any
changes to the graphics state will not be visible outside the
group.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist><para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-get-group-target" role="function" condition="since:1.2"/>cairo_get_group_target ()</title>
<indexterm role="1.2"><primary>cairo_get_group_target</primary></indexterm><programlisting><link linkend="cairo-surface-t">cairo_surface_t</link>* cairo_get_group_target     (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the target surface for the current group as started by the
most recent call to <link linkend="cairo-push-group"><function>cairo_push_group()</function></link> or
<link linkend="cairo-push-group-with-content"><function>cairo_push_group_with_content()</function></link>.
</para>
<para>
This function will return NULL if called "outside" of any group
rendering blocks, (that is, after the last balancing call to
<link linkend="cairo-pop-group"><function>cairo_pop_group()</function></link> or <link linkend="cairo-pop-group-to-source"><function>cairo_pop_group_to_source()</function></link>).</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the target group surface, or NULL if none.  This
object is owned by cairo. To keep a reference to it, you must call
<link linkend="cairo-surface-reference"><function>cairo_surface_reference()</function></link>.

</simpara></listitem></varlistentry>
</variablelist><para>Since  1.2
</para></refsect2>
<refsect2>
<title><anchor id="cairo-set-source-rgb" role="function"/>cairo_set_source_rgb ()</title>
<indexterm><primary>cairo_set_source_rgb</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_source_rgb            (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> red,
                                             <link linkend="double">double</link> green,
                                             <link linkend="double">double</link> blue);</programlisting>
<para>
Sets the source pattern within <parameter>cr</parameter> to an opaque color. This opaque
color will then be used for any subsequent drawing operation until
a new source pattern is set.
</para>
<para>
The color components are floating point numbers in the range 0 to
1. If the values passed in are outside that range, they will be
clamped.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>red</parameter>&nbsp;:</term>
<listitem><simpara> red component of color
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>green</parameter>&nbsp;:</term>
<listitem><simpara> green component of color
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>blue</parameter>&nbsp;:</term>
<listitem><simpara> blue component of color
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-source-rgba" role="function"/>cairo_set_source_rgba ()</title>
<indexterm><primary>cairo_set_source_rgba</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_source_rgba           (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> red,
                                             <link linkend="double">double</link> green,
                                             <link linkend="double">double</link> blue,
                                             <link linkend="double">double</link> alpha);</programlisting>
<para>
Sets the source pattern within <parameter>cr</parameter> to a translucent color. This
color will then be used for any subsequent drawing operation until
a new source pattern is set.
</para>
<para>
The color and alpha components are floating point numbers in the
range 0 to 1. If the values passed in are outside that range, they
will be clamped.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>red</parameter>&nbsp;:</term>
<listitem><simpara> red component of color
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>green</parameter>&nbsp;:</term>
<listitem><simpara> green component of color
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>blue</parameter>&nbsp;:</term>
<listitem><simpara> blue component of color
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>alpha</parameter>&nbsp;:</term>
<listitem><simpara> alpha component of color
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-source" role="function"/>cairo_set_source ()</title>
<indexterm><primary>cairo_set_source</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_source                (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-pattern-t">cairo_pattern_t</link> *source);</programlisting>
<para>
Sets the source pattern within <parameter>cr</parameter> to <parameter>source</parameter>. This pattern
will then be used for any subsequent drawing operation until a new
source pattern is set.
</para>
<para>
Note: The pattern's transformation matrix will be locked to the
user space in effect at the time of <link linkend="cairo-set-source"><function>cairo_set_source()</function></link>. This means
that further modifications of the current transformation matrix
will not affect the source pattern. See <link linkend="cairo-pattern-set-matrix"><function>cairo_pattern_set_matrix()</function></link>.
</para>
<para>
XXX: I'd also like to direct the reader's attention to some
(not-yet-written) section on cairo's imaging model. How would I do
that if such a section existed? (cworth).</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>source</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-pattern-t"><type>cairo_pattern_t</type></link> to be used as the source for
subsequent drawing operations.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-source-surface" role="function"/>cairo_set_source_surface ()</title>
<indexterm><primary>cairo_set_source_surface</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_source_surface        (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-surface-t">cairo_surface_t</link> *surface,
                                             <link linkend="double">double</link> x,
                                             <link linkend="double">double</link> y);</programlisting>
<para>
This is a convenience function for creating a pattern from <parameter>surface</parameter>
and setting it as the source in <parameter>cr</parameter> with <link linkend="cairo-set-source"><function>cairo_set_source()</function></link>.
</para>
<para>
The <parameter>x</parameter> and <parameter>y</parameter> parameters give the user-space coordinate at which
the surface origin should appear. (The surface origin is its
upper-left corner before any transformation has been applied.) The
<parameter>x</parameter> and <parameter>y</parameter> patterns are negated and then set as translation values
in the pattern matrix.
</para>
<para>
Other than the initial translation pattern matrix, as described
above, all other pattern attributes, (such as its extend mode), are
set to the default values as in <link linkend="cairo-pattern-create-for-surface"><function>cairo_pattern_create_for_surface()</function></link>.
The resulting pattern can be queried with <link linkend="cairo-get-source"><function>cairo_get_source()</function></link> so
that these attributes can be modified if desired, (eg. to create a
repeating pattern with <link linkend="cairo-pattern-set-extend"><function>cairo_pattern_set_extend()</function></link>).</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>surface</parameter>&nbsp;:</term>
<listitem><simpara> a surface to be used to set the source pattern
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x</parameter>&nbsp;:</term>
<listitem><simpara> User-space X coordinate for surface origin
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y</parameter>&nbsp;:</term>
<listitem><simpara> User-space Y coordinate for surface origin
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-source" role="function"/>cairo_get_source ()</title>
<indexterm><primary>cairo_get_source</primary></indexterm><programlisting><link linkend="cairo-pattern-t">cairo_pattern_t</link>* cairo_get_source           (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the current source pattern for <parameter>cr</parameter>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current source pattern. This object is owned by
cairo. To keep a reference to it, you must call
<link linkend="cairo-pattern-reference"><function>cairo_pattern_reference()</function></link>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-antialias-t" role="enum"/>enum cairo_antialias_t</title>
<indexterm><primary>cairo_antialias_t</primary></indexterm><programlisting>typedef enum _cairo_antialias {
    CAIRO_ANTIALIAS_DEFAULT,
    CAIRO_ANTIALIAS_NONE,
    CAIRO_ANTIALIAS_GRAY,
    CAIRO_ANTIALIAS_SUBPIXEL
} cairo_antialias_t;
</programlisting>
<para>
Specifies the type of antialiasing to do when rendering text or shapes.</para>
<para>

</para><variablelist role="enum">
<varlistentry>
<term><anchor id="CAIRO-ANTIALIAS-DEFAULT:CAPS" role="constant"/><literal>CAIRO_ANTIALIAS_DEFAULT</literal></term>
<listitem><simpara> Use the default antialiasing for
  the subsystem and target device
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><anchor id="CAIRO-ANTIALIAS-NONE:CAPS" role="constant"/><literal>CAIRO_ANTIALIAS_NONE</literal></term>
<listitem><simpara> Use a bilevel alpha mask
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><anchor id="CAIRO-ANTIALIAS-GRAY:CAPS" role="constant"/><literal>CAIRO_ANTIALIAS_GRAY</literal></term>
<listitem><simpara> Perform single-color antialiasing (using
 shades of gray for black text on a white background, for example).
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><anchor id="CAIRO-ANTIALIAS-SUBPIXEL:CAPS" role="constant"/><literal>CAIRO_ANTIALIAS_SUBPIXEL</literal></term>
<listitem><simpara> Perform antialiasing by taking
 advantage of the order of subpixel elements on devices
 such as LCD panels
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-antialias" role="function"/>cairo_set_antialias ()</title>
<indexterm><primary>cairo_set_antialias</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_antialias             (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-antialias-t">cairo_antialias_t</link> antialias);</programlisting>
<para>
Set the antialiasing mode of the rasterizer used for drawing shapes.
This value is a hint, and a particular backend may or may not support
a particular value.  At the current time, no backend supports
<link linkend="CAIRO-ANTIALIAS-SUBPIXEL:CAPS"><literal>CAIRO_ANTIALIAS_SUBPIXEL</literal></link> when drawing shapes.
</para>
<para>
Note that this option does not affect text rendering, instead see
<link linkend="cairo-font-options-set-antialias"><function>cairo_font_options_set_antialias()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>antialias</parameter>&nbsp;:</term>
<listitem><simpara> the new antialiasing mode
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-antialias" role="function"/>cairo_get_antialias ()</title>
<indexterm><primary>cairo_get_antialias</primary></indexterm><programlisting><link linkend="cairo-antialias-t">cairo_antialias_t</link> cairo_get_antialias       (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the current shape antialiasing mode, as set by <link linkend="cairo-set-shape-antialias"><function>cairo_set_shape_antialias()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current shape antialiasing mode.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-dash" role="function"/>cairo_set_dash ()</title>
<indexterm><primary>cairo_set_dash</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_dash                  (<link linkend="cairo-t">cairo_t</link> *cr,
                                             const <link linkend="double">double</link> *dashes,
                                             <link linkend="int">int</link> num_dashes,
                                             <link linkend="double">double</link> offset);</programlisting>
<para>
Sets the dash pattern to be used by <link linkend="cairo-stroke"><function>cairo_stroke()</function></link>. A dash pattern
is specified by <parameter>dashes</parameter>, an array of positive values. Each value
provides the length of alternate "on" and "off" portions of the
stroke. The <parameter>offset</parameter> specifies an offset into the pattern at which
the stroke begins.
</para>
<para>
Each "on" segment will have caps applied as if the segment were a
separate sub-path. In particular, it is valid to use an "on" length
of 0.0 with CAIRO_LINE_CAP_ROUND or CAIRO_LINE_CAP_SQUARE in order
to distributed dots or squares along a path.
</para>
<para>
Note: The length values are in user-space units as evaluated at the
time of stroking. This is not necessarily the same as the user
space at the time of <link linkend="cairo-set-dash"><function>cairo_set_dash()</function></link>.
</para>
<para>
If <parameter>num_dashes</parameter> is 0 dashing is disabled.
</para>
<para>
If <parameter>num_dashes</parameter> is 1 a symmetric pattern is assumed with alternating
on and off portions of the size specified by the single value in
<parameter>dashes</parameter>.
</para>
<para>
If any value in <parameter>dashes</parameter> is negative, or if all values are 0, then
<parameter>cairo_t</parameter> will be put into an error state with a status of
<link linkend="CAIRO-STATUS-INVALID-DASH:CAPS"><type>CAIRO_STATUS_INVALID_DASH</type></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>dashes</parameter>&nbsp;:</term>
<listitem><simpara> an array specifying alternate lengths of on and off stroke portions
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>num_dashes</parameter>&nbsp;:</term>
<listitem><simpara> the length of the dashes array
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>offset</parameter>&nbsp;:</term>
<listitem><simpara> an offset into the dash pattern at which the stroke should start
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-fill-rule-t" role="enum"/>enum cairo_fill_rule_t</title>
<indexterm><primary>cairo_fill_rule_t</primary></indexterm><programlisting>typedef enum _cairo_fill_rule {
    CAIRO_FILL_RULE_WINDING,
    CAIRO_FILL_RULE_EVEN_ODD
} cairo_fill_rule_t;
</programlisting>
<para>
<link linkend="cairo-fill-rule-t"><type>cairo_fill_rule_t</type></link> is used to select how paths are filled. For both
fill rules, whether or not a point is included in the fill is
determined by taking a ray from that point to infinity and looking
at intersections with the path. The ray can be in any direction,
as long as it doesn't pass through the end point of a segment
or have a tricky intersection such as intersecting tangent to the path.
(Note that filling is not actually implemented in this way. This
is just a description of the rule that is applied.)
</para>
<para>
New entries may be added in future versions.</para>
<para>

</para><variablelist role="enum">
<varlistentry>
<term><anchor id="CAIRO-FILL-RULE-WINDING:CAPS" role="constant"/><literal>CAIRO_FILL_RULE_WINDING</literal></term>
<listitem><simpara> If the path crosses the ray from
left-to-right, counts +1. If the path crosses the ray
from right to left, counts -1. (Left and right are determined
from the perspective of looking along the ray from the starting
point.) If the total count is non-zero, the point will be filled.
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><anchor id="CAIRO-FILL-RULE-EVEN-ODD:CAPS" role="constant"/><literal>CAIRO_FILL_RULE_EVEN_ODD</literal></term>
<listitem><simpara> Counts the total number of
intersections, without regard to the orientation of the contour. If
the total number of intersections is odd, the point will be
filled.
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-fill-rule" role="function"/>cairo_set_fill_rule ()</title>
<indexterm><primary>cairo_set_fill_rule</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_fill_rule             (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-fill-rule-t">cairo_fill_rule_t</link> fill_rule);</programlisting>
<para>
Set the current fill rule within the cairo context. The fill rule
is used to determine which regions are inside or outside a complex
(potentially self-intersecting) path. The current fill rule affects
both cairo_fill and cairo_clip. See <link linkend="cairo-fill-rule-t"><type>cairo_fill_rule_t</type></link> for details
on the semantics of each available fill rule.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>fill_rule</parameter>&nbsp;:</term>
<listitem><simpara> a fill rule, specified as a <link linkend="cairo-fill-rule-t"><type>cairo_fill_rule_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-fill-rule" role="function"/>cairo_get_fill_rule ()</title>
<indexterm><primary>cairo_get_fill_rule</primary></indexterm><programlisting><link linkend="cairo-fill-rule-t">cairo_fill_rule_t</link> cairo_get_fill_rule       (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the current fill rule, as set by <link linkend="cairo-set-fill-rule"><function>cairo_set_fill_rule()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current fill rule.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-line-cap-t" role="enum"/>enum cairo_line_cap_t</title>
<indexterm><primary>cairo_line_cap_t</primary></indexterm><programlisting>typedef enum _cairo_line_cap {
    CAIRO_LINE_CAP_BUTT,
    CAIRO_LINE_CAP_ROUND,
    CAIRO_LINE_CAP_SQUARE
} cairo_line_cap_t;
</programlisting>
<para>
enumeration for style of line-endings</para>
<para>

</para><variablelist role="enum">
<varlistentry>
<term><anchor id="CAIRO-LINE-CAP-BUTT:CAPS" role="constant"/><literal>CAIRO_LINE_CAP_BUTT</literal></term>
<listitem><simpara> start(stop) the line exactly at the start(end) point
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><anchor id="CAIRO-LINE-CAP-ROUND:CAPS" role="constant"/><literal>CAIRO_LINE_CAP_ROUND</literal></term>
<listitem><simpara> use a round ending, the center of the circle is the end point
</simpara></listitem>
</varlistentry>
<varlistentry>
<term><anchor id="CAIRO-LINE-CAP-SQUARE:CAPS" role="constant"/><literal>CAIRO_LINE_CAP_SQUARE</literal></term>
<listitem><simpara> use squared ending, the center of the square is the end point
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-line-cap" role="function"/>cairo_set_line_cap ()</title>
<indexterm><primary>cairo_set_line_cap</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_line_cap              (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-line-cap-t">cairo_line_cap_t</link> line_cap);</programlisting>
<para>
Sets the current line cap style within the cairo context. See
<link linkend="cairo-line-cap-t"><type>cairo_line_cap_t</type></link> for details about how the available line cap
styles are drawn.
</para>
<para>
As with the other stroke parameters, the current line cap style is
examined by <link linkend="cairo-stroke"><function>cairo_stroke()</function></link>, <link linkend="cairo-stroke-extents"><function>cairo_stroke_extents()</function></link>, and
<link linkend="cairo-stroke-to-path"><function>cairo_stroke_to_path()</function></link>, but does not have any effect during path
construction.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context, as a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>line_cap</parameter>&nbsp;:</term>
<listitem><simpara> a line cap style, as a <link linkend="cairo-line-cap-t"><type>cairo_line_cap_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-line-cap" role="function"/>cairo_get_line_cap ()</title>
<indexterm><primary>cairo_get_line_cap</primary></indexterm><programlisting><link linkend="cairo-line-cap-t">cairo_line_cap_t</link> cairo_get_line_cap         (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the current line cap style, as set by <link linkend="cairo-set-line-cap"><function>cairo_set_line_cap()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current line cap style.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-line-join-t" role="enum"/>enum cairo_line_join_t</title>
<indexterm><primary>cairo_line_join_t</primary></indexterm><programlisting>typedef enum _cairo_line_join {
    CAIRO_LINE_JOIN_MITER,
    CAIRO_LINE_JOIN_ROUND,
    CAIRO_LINE_JOIN_BEVEL
} cairo_line_join_t;
</programlisting>
<para>

</para></refsect2>
<refsect2>
<title><anchor id="cairo-set-line-join" role="function"/>cairo_set_line_join ()</title>
<indexterm><primary>cairo_set_line_join</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_line_join             (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-line-join-t">cairo_line_join_t</link> line_join);</programlisting>
<para>
Sets the current line join style within the cairo context. See
<link linkend="cairo-line-join-t"><type>cairo_line_join_t</type></link> for details about how the available line join
styles are drawn.
</para>
<para>
As with the other stroke parameters, the current line join style is
examined by <link linkend="cairo-stroke"><function>cairo_stroke()</function></link>, <link linkend="cairo-stroke-extents"><function>cairo_stroke_extents()</function></link>, and
<link linkend="cairo-stroke-to-path"><function>cairo_stroke_to_path()</function></link>, but does not have any effect during path
construction.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context, as a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>line_join</parameter>&nbsp;:</term>
<listitem><simpara> a line joint style, as a <link linkend="cairo-line-join-t"><type>cairo_line_join_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-line-join" role="function"/>cairo_get_line_join ()</title>
<indexterm><primary>cairo_get_line_join</primary></indexterm><programlisting><link linkend="cairo-line-join-t">cairo_line_join_t</link> cairo_get_line_join       (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the current line join style, as set by <link linkend="cairo-set-line-join"><function>cairo_set_line_join()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current line join style.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-line-width" role="function"/>cairo_set_line_width ()</title>
<indexterm><primary>cairo_set_line_width</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_line_width            (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> width);</programlisting>
<para>
Sets the current line width within the cairo context. The line
width value specifies the diameter of a pen that is circular in
user space, (though device-space pen may be an ellipse in general
due to scaling/shear/rotation of the CTM).
</para>
<para>
Note: When the description above refers to user space and CTM it
refers to the user space and CTM in effect at the time of the
stroking operation, not the user space and CTM in effect at the
time of the call to <link linkend="cairo-set-line-width"><function>cairo_set_line_width()</function></link>. The simplest usage
makes both of these spaces identical. That is, if there is no
change to the CTM between a call to <link linkend="cairo-set-line-with"><function>cairo_set_line_with()</function></link> and the
stroking operation, then one can just pass user-space values to
<link linkend="cairo-set-line-width"><function>cairo_set_line_width()</function></link> and ignore this note.
</para>
<para>
As with the other stroke parameters, the current line width is
examined by <link linkend="cairo-stroke"><function>cairo_stroke()</function></link>, <link linkend="cairo-stroke-extents"><function>cairo_stroke_extents()</function></link>, and
<link linkend="cairo-stroke-to-path"><function>cairo_stroke_to_path()</function></link>, but does not have any effect during path
construction.
</para>
<para>
The default line width value is 2.0.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>width</parameter>&nbsp;:</term>
<listitem><simpara> a line width
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-line-width" role="function"/>cairo_get_line_width ()</title>
<indexterm><primary>cairo_get_line_width</primary></indexterm><programlisting><link linkend="double">double</link>      cairo_get_line_width            (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current line width value exactly as set by
<link linkend="cairo-set-line-width"><function>cairo_set_line_width()</function></link>. Note that the value is unchanged even if
the CTM has changed between the calls to <link linkend="cairo-set-line-width"><function>cairo_set_line_width()</function></link> and
<link linkend="cairo-get-line-width"><function>cairo_get_line_width()</function></link>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-miter-limit" role="function"/>cairo_set_miter_limit ()</title>
<indexterm><primary>cairo_set_miter_limit</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_miter_limit           (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> limit);</programlisting>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>limit</parameter>&nbsp;:</term>
<listitem><simpara>


</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-miter-limit" role="function"/>cairo_get_miter_limit ()</title>
<indexterm><primary>cairo_get_miter_limit</primary></indexterm><programlisting><link linkend="double">double</link>      cairo_get_miter_limit           (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the current miter limit, as set by <link linkend="cairo-set-miter-limit"><function>cairo_set_miter_limit()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current miter limit.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-operator-t" role="enum"/>enum cairo_operator_t</title>
<indexterm><primary>cairo_operator_t</primary></indexterm><programlisting>typedef enum _cairo_operator {
    CAIRO_OPERATOR_CLEAR,

    CAIRO_OPERATOR_SOURCE,
    CAIRO_OPERATOR_OVER,
    CAIRO_OPERATOR_IN,
    CAIRO_OPERATOR_OUT,
    CAIRO_OPERATOR_ATOP,

    CAIRO_OPERATOR_DEST,
    CAIRO_OPERATOR_DEST_OVER,
    CAIRO_OPERATOR_DEST_IN,
    CAIRO_OPERATOR_DEST_OUT,
    CAIRO_OPERATOR_DEST_ATOP,

    CAIRO_OPERATOR_XOR,
    CAIRO_OPERATOR_ADD,
    CAIRO_OPERATOR_SATURATE
} cairo_operator_t;
</programlisting>
<para>

</para></refsect2>
<refsect2>
<title><anchor id="cairo-set-operator" role="function"/>cairo_set_operator ()</title>
<indexterm><primary>cairo_set_operator</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_operator              (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-operator-t">cairo_operator_t</link> op);</programlisting>
<para>
Sets the compositing operator to be used for all drawing
operations. See <link linkend="cairo-operator-t"><type>cairo_operator_t</type></link> for details on the semantics of
each available compositing operator.
</para>
<para>
XXX: I'd also like to direct the reader's attention to some
(not-yet-written) section on cairo's imaging model. How would I do
that if such a section existed? (cworth).</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>op</parameter>&nbsp;:</term>
<listitem><simpara> a compositing operator, specified as a <link linkend="cairo-operator-t"><type>cairo_operator_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-operator" role="function"/>cairo_get_operator ()</title>
<indexterm><primary>cairo_get_operator</primary></indexterm><programlisting><link linkend="cairo-operator-t">cairo_operator_t</link> cairo_get_operator         (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the current compositing operator for a cairo context.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current compositing operator.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-set-tolerance" role="function"/>cairo_set_tolerance ()</title>
<indexterm><primary>cairo_set_tolerance</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_set_tolerance             (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> tolerance);</programlisting>
<para>
Sets the tolerance used when converting paths into trapezoids.
Curved segments of the path will be subdivided until the maximum
deviation between the original path and the polygonal approximation
is less than <parameter>tolerance</parameter>. The default value is 0.1. A larger
value will give better performance, a smaller value, better
appearance. (Reducing the value from the default value of 0.1
is unlikely to improve appearance significantly.)</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-t"><type>cairo_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>tolerance</parameter>&nbsp;:</term>
<listitem><simpara> the tolerance, in device units (typically pixels)
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-get-tolerance" role="function"/>cairo_get_tolerance ()</title>
<indexterm><primary>cairo_get_tolerance</primary></indexterm><programlisting><link linkend="double">double</link>      cairo_get_tolerance             (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Gets the current tolerance value, as set by <link linkend="cairo-set-tolerance"><function>cairo_set_tolerance()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara> the current tolerance value.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-clip" role="function"/>cairo_clip ()</title>
<indexterm><primary>cairo_clip</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_clip                      (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Establishes a new clip region by intersecting the current clip
region with the current path as it would be filled by <link linkend="cairo-fill"><function>cairo_fill()</function></link>
and according to the current fill rule (see <link linkend="cairo-set-fill-rule"><function>cairo_set_fill_rule()</function></link>).
</para>
<para>
After cairo_clip, the current path will be cleared from the cairo
context.
</para>
<para>
The current clip region affects all drawing operations by
effectively masking out any changes to the surface that are outside
the current clip region.
</para>
<para>
Calling <link linkend="cairo-clip"><function>cairo_clip()</function></link> can only make the clip region smaller, never
larger. But the current clip is part of the graphics state, so a
temporary restriction of the clip region can be achieved by
calling <link linkend="cairo-clip"><function>cairo_clip()</function></link> within a <link linkend="cairo-save"><function>cairo_save()</function></link>/<link linkend="cairo-restore"><function>cairo_restore()</function></link>
pair. The only other means of increasing the size of the clip
region is <link linkend="cairo-reset-clip"><function>cairo_reset_clip()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-clip-preserve" role="function"/>cairo_clip_preserve ()</title>
<indexterm><primary>cairo_clip_preserve</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_clip_preserve             (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Establishes a new clip region by intersecting the current clip
region with the current path as it would be filled by <link linkend="cairo-fill"><function>cairo_fill()</function></link>
and according to the current fill rule (see <link linkend="cairo-set-fill-rule"><function>cairo_set_fill_rule()</function></link>).
</para>
<para>
Unlike <link linkend="cairo-clip"><function>cairo_clip()</function></link>, cairo_clip_preserve preserves the path within
the cairo context.
</para>
<para>
The current clip region affects all drawing operations by
effectively masking out any changes to the surface that are outside
the current clip region.
</para>
<para>
Calling <link linkend="cairo-clip"><function>cairo_clip()</function></link> can only make the clip region smaller, never
larger. But the current clip is part of the graphics state, so a
temporary restriction of the clip region can be achieved by
calling <link linkend="cairo-clip"><function>cairo_clip()</function></link> within a <link linkend="cairo-save"><function>cairo_save()</function></link>/<link linkend="cairo-restore"><function>cairo_restore()</function></link>
pair. The only other means of increasing the size of the clip
region is <link linkend="cairo-reset-clip"><function>cairo_reset_clip()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-reset-clip" role="function"/>cairo_reset_clip ()</title>
<indexterm><primary>cairo_reset_clip</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_reset_clip                (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Reset the current clip region to its original, unrestricted
state. That is, set the clip region to an infinitely large shape
containing the target surface. Equivalently, if infinity is too
hard to grasp, one can imagine the clip region being reset to the
exact bounds of the target surface.
</para>
<para>
Note that code meant to be reusable should not call
<link linkend="cairo-reset-clip"><function>cairo_reset_clip()</function></link> as it will cause results unexpected by
higher-level code which calls <link linkend="cairo-clip"><function>cairo_clip()</function></link>. Consider using
<link linkend="cairo-save"><function>cairo_save()</function></link> and <link linkend="cairo-restore"><function>cairo_restore()</function></link> around <link linkend="cairo-clip"><function>cairo_clip()</function></link> as a more
robust means of temporarily restricting the clip region.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-fill" role="function"/>cairo_fill ()</title>
<indexterm><primary>cairo_fill</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_fill                      (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
A drawing operator that fills the current path according to the
current fill rule, (each sub-path is implicitly closed before being
filled). After cairo_fill, the current path will be cleared from
the cairo context. See <link linkend="cairo-set-fill-rule"><function>cairo_set_fill_rule()</function></link> and
<link linkend="cairo-fill-preserve"><function>cairo_fill_preserve()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-fill-preserve" role="function"/>cairo_fill_preserve ()</title>
<indexterm><primary>cairo_fill_preserve</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_fill_preserve             (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
A drawing operator that fills the current path according to the
current fill rule, (each sub-path is implicitly closed before being
filled). Unlike <link linkend="cairo-fill"><function>cairo_fill()</function></link>, cairo_fill_preserve preserves the
path within the cairo context.
</para>
<para>
See <link linkend="cairo-set-fill-rule"><function>cairo_set_fill_rule()</function></link> and <link linkend="cairo-fill"><function>cairo_fill()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-fill-extents" role="function"/>cairo_fill_extents ()</title>
<indexterm><primary>cairo_fill_extents</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_fill_extents              (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> *x1,
                                             <link linkend="double">double</link> *y1,
                                             <link linkend="double">double</link> *x2,
                                             <link linkend="double">double</link> *y2);</programlisting>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x1</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y1</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x2</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y2</parameter>&nbsp;:</term>
<listitem><simpara>


</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-in-fill" role="function"/>cairo_in_fill ()</title>
<indexterm><primary>cairo_in_fill</primary></indexterm><programlisting><link linkend="cairo-bool-t">cairo_bool_t</link> cairo_in_fill                  (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> x,
                                             <link linkend="double">double</link> y);</programlisting>
<para>
Tests whether the given point is on the area filled by doing a
<link linkend="cairo-stroke"><function>cairo_stroke()</function></link> operation on <parameter>cr</parameter> given the current path and filling
parameters.
</para>
<para>
See <link linkend="cairo-fill"><function>cairo_fill()</function></link>, <link linkend="cairo-set-fill-rule"><function>cairo_set_fill_rule()</function></link> and <link linkend="cairo-fill-preserve"><function>cairo_fill_preserve()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x</parameter>&nbsp;:</term>
<listitem><simpara> X coordinate of the point to test
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y</parameter>&nbsp;:</term>
<listitem><simpara> Y coordinate of the point to test
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara>


</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-mask" role="function"/>cairo_mask ()</title>
<indexterm><primary>cairo_mask</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_mask                      (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-pattern-t">cairo_pattern_t</link> *pattern);</programlisting>
<para>
A drawing operator that paints the current source
using the alpha channel of <parameter>pattern</parameter> as a mask. (Opaque
areas of <parameter>pattern</parameter> are painted with the source, transparent
areas are not painted.)</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>pattern</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-pattern-t"><type>cairo_pattern_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-mask-surface" role="function"/>cairo_mask_surface ()</title>
<indexterm><primary>cairo_mask_surface</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_mask_surface              (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="cairo-surface-t">cairo_surface_t</link> *surface,
                                             <link linkend="double">double</link> surface_x,
                                             <link linkend="double">double</link> surface_y);</programlisting>
<para>
A drawing operator that paints the current source
using the alpha channel of <parameter>surface</parameter> as a mask. (Opaque
areas of <parameter>surface</parameter> are painted with the source, transparent
areas are not painted.)</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>surface</parameter>&nbsp;:</term>
<listitem><simpara> a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>surface_x</parameter>&nbsp;:</term>
<listitem><simpara> X coordinate at which to place the origin of <parameter>surface</parameter>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>surface_y</parameter>&nbsp;:</term>
<listitem><simpara> Y coordinate at which to place the origin of <parameter>surface</parameter>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-paint" role="function"/>cairo_paint ()</title>
<indexterm><primary>cairo_paint</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_paint                     (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
A drawing operator that paints the current source everywhere within
the current clip region.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-paint-with-alpha" role="function"/>cairo_paint_with_alpha ()</title>
<indexterm><primary>cairo_paint_with_alpha</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_paint_with_alpha          (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> alpha);</programlisting>
<para>
A drawing operator that paints the current source everywhere within
the current clip region using a mask of constant alpha value
<parameter>alpha</parameter>. The effect is similar to <link linkend="cairo-paint"><function>cairo_paint()</function></link>, but the drawing
is faded out using the alpha value.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>alpha</parameter>&nbsp;:</term>
<listitem><simpara> alpha value, between 0 (transparent) and 1 (opaque)
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-stroke" role="function"/>cairo_stroke ()</title>
<indexterm><primary>cairo_stroke</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_stroke                    (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
A drawing operator that strokes the current path according to the
current line width, line join, line cap, and dash settings. After
cairo_stroke, the current path will be cleared from the cairo
context. See <link linkend="cairo-set-line-width"><function>cairo_set_line_width()</function></link>, <link linkend="cairo-set-line-join"><function>cairo_set_line_join()</function></link>,
<link linkend="cairo-set-line-cap"><function>cairo_set_line_cap()</function></link>, <link linkend="cairo-set-dash"><function>cairo_set_dash()</function></link>, and
<link linkend="cairo-stroke-preserve"><function>cairo_stroke_preserve()</function></link>.
</para>
<para>
Note: Degenerate segments and sub-paths are treated specially and
provide a useful result. These can result in two different
situations:
</para>
<para>
1. Zero-length "on" segments set in <link linkend="cairo-set-dash"><function>cairo_set_dash()</function></link>. If the cap
style is CAIRO_LINE_CAP_ROUND or CAIRO_LINE_CAP_SQUARE then these
segments will be drawn as circular dots or squares respectively. In
the case of CAIRO_LINE_CAP_SQUARE, the orientation of the squares
is determined by the direction of the underlying path.
</para>
<para>
2. A sub-path created by <link linkend="cairo-move-to"><function>cairo_move_to()</function></link> followed by either a
<link linkend="cairo-close-path"><function>cairo_close_path()</function></link> or one or more calls to <link linkend="cairo-line-to"><function>cairo_line_to()</function></link> to the
same coordinate as the <link linkend="cairo-move-to"><function>cairo_move_to()</function></link>. If the cap style is
CAIRO_LINE_CAP_ROUND then these sub-paths will be drawn as circular
dots. Note that in the case of CAIRO_LINE_CAP_SQUARE a degenerate
sub-path will not be drawn at all, (since the correct orientation
is indeterminate).
</para>
<para>
In no case will a cap style of CAIRO_LINE_CAP_BUTT cause anything
to be drawn in the case of either degenerate segments or sub-paths.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-stroke-preserve" role="function"/>cairo_stroke_preserve ()</title>
<indexterm><primary>cairo_stroke_preserve</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_stroke_preserve           (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
A drawing operator that strokes the current path according to the
current line width, line join, line cap, and dash settings. Unlike
<link linkend="cairo-stroke"><function>cairo_stroke()</function></link>, cairo_stroke_preserve preserves the path within the
cairo context.
</para>
<para>
See <link linkend="cairo-set-line-width"><function>cairo_set_line_width()</function></link>, <link linkend="cairo-set-line-join"><function>cairo_set_line_join()</function></link>,
<link linkend="cairo-set-line-cap"><function>cairo_set_line_cap()</function></link>, <link linkend="cairo-set-dash"><function>cairo_set_dash()</function></link>, and
<link linkend="cairo-stroke-preserve"><function>cairo_stroke_preserve()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-stroke-extents" role="function"/>cairo_stroke_extents ()</title>
<indexterm><primary>cairo_stroke_extents</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_stroke_extents            (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> *x1,
                                             <link linkend="double">double</link> *y1,
                                             <link linkend="double">double</link> *x2,
                                             <link linkend="double">double</link> *y2);</programlisting>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x1</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y1</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x2</parameter>&nbsp;:</term>
<listitem><simpara>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y2</parameter>&nbsp;:</term>
<listitem><simpara>


</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-in-stroke" role="function"/>cairo_in_stroke ()</title>
<indexterm><primary>cairo_in_stroke</primary></indexterm><programlisting><link linkend="cairo-bool-t">cairo_bool_t</link> cairo_in_stroke                (<link linkend="cairo-t">cairo_t</link> *cr,
                                             <link linkend="double">double</link> x,
                                             <link linkend="double">double</link> y);</programlisting>
<para>
Tests whether the given point is on the area stroked by doing a
<link linkend="cairo-stroke"><function>cairo_stroke()</function></link> operation on <parameter>cr</parameter> given the current path and stroking
parameters.
</para>
<para>
See cairo_stroke, <link linkend="cairo-set-line-width"><function>cairo_set_line_width()</function></link>, <link linkend="cairo-set-line-join"><function>cairo_set_line_join()</function></link>,
<link linkend="cairo-set-line-cap"><function>cairo_set_line_cap()</function></link>, <link linkend="cairo-set-dash"><function>cairo_set_dash()</function></link>, and
<link linkend="cairo-stroke-preserve"><function>cairo_stroke_preserve()</function></link>.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x</parameter>&nbsp;:</term>
<listitem><simpara> X coordinate of the point to test
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y</parameter>&nbsp;:</term>
<listitem><simpara> Y coordinate of the point to test
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&nbsp;:</term><listitem><simpara>


</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-copy-page" role="function"/>cairo_copy_page ()</title>
<indexterm><primary>cairo_copy_page</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_copy_page                 (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Emits the current page for backends that support multiple pages, but
doesn't clear it, so, the contents of the current page will be retained
for the next page too.  Use <link linkend="cairo-show-page"><function>cairo_show_page()</function></link> if you want to get an
empty page after the emission.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-show-page" role="function"/>cairo_show_page ()</title>
<indexterm><primary>cairo_show_page</primary></indexterm><programlisting><link linkend="void">void</link>        cairo_show_page                 (<link linkend="cairo-t">cairo_t</link> *cr);</programlisting>
<para>
Emits and clears the current page for backends that support multiple
pages.  Use <link linkend="cairo-copy-page"><function>cairo_copy_page()</function></link> if you don't want to clear the page.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&nbsp;:</term>
<listitem><simpara> a cairo context
</simpara></listitem></varlistentry>
</variablelist></refsect2>

</refsect1>




</refentry>