cairo-scaled-font.xml [plain text]
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<refentry id="cairo-cairo-scaled-font-t">
<refmeta>
<refentrytitle role="top_of_page" id="cairo-cairo-scaled-font-t.top_of_page">cairo_scaled_font_t</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>
CAIRO Library
</refmiscinfo>
</refmeta>
<refnamediv>
<refname>cairo_scaled_font_t</refname>
<refpurpose>Font face at particular size and options</refpurpose>
</refnamediv>
<refsynopsisdiv id="cairo-cairo-scaled-font-t.synopsis" role="synopsis">
<title role="synopsis.title">Synopsis</title>
<synopsis>typedef <link linkend="cairo-scaled-font-t">cairo_scaled_font_t</link>;
<link linkend="cairo-scaled-font-t"><returnvalue>cairo_scaled_font_t</returnvalue></link> * <link linkend="cairo-scaled-font-create">cairo_scaled_font_create</link> (<parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>,
<parameter>const <link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *font_matrix</parameter>,
<parameter>const <link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *ctm</parameter>,
<parameter>const <link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> *options</parameter>);
<link linkend="cairo-scaled-font-t"><returnvalue>cairo_scaled_font_t</returnvalue></link> * <link linkend="cairo-scaled-font-reference">cairo_scaled_font_reference</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link> <link linkend="cairo-scaled-font-destroy">cairo_scaled_font_destroy</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);
<link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> <link linkend="cairo-scaled-font-status">cairo_scaled_font_status</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);
<link linkend="cairo-font-extents-t">cairo_font_extents_t</link>;
<link linkend="void"><returnvalue>void</returnvalue></link> <link linkend="cairo-scaled-font-extents">cairo_scaled_font_extents</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-font-extents-t"><type>cairo_font_extents_t</type></link> *extents</parameter>);
<link linkend="cairo-text-extents-t">cairo_text_extents_t</link>;
<link linkend="void"><returnvalue>void</returnvalue></link> <link linkend="cairo-scaled-font-text-extents">cairo_scaled_font_text_extents</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter>const <link linkend="char"><type>char</type></link> *utf8</parameter>,
<parameter><link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> *extents</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link> <link linkend="cairo-scaled-font-glyph-extents">cairo_scaled_font_glyph_extents</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter>const <link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link> *glyphs</parameter>,
<parameter><link linkend="int"><type>int</type></link> num_glyphs</parameter>,
<parameter><link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> *extents</parameter>);
<link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> <link linkend="cairo-scaled-font-text-to-glyphs">cairo_scaled_font_text_to_glyphs</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="double"><type>double</type></link> x</parameter>,
<parameter><link linkend="double"><type>double</type></link> y</parameter>,
<parameter>const <link linkend="char"><type>char</type></link> *utf8</parameter>,
<parameter><link linkend="int"><type>int</type></link> utf8_len</parameter>,
<parameter><link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link> **glyphs</parameter>,
<parameter><link linkend="int"><type>int</type></link> *num_glyphs</parameter>,
<parameter><link linkend="cairo-text-cluster-t"><type>cairo_text_cluster_t</type></link> **clusters</parameter>,
<parameter><link linkend="int"><type>int</type></link> *num_clusters</parameter>,
<parameter><link linkend="cairo-text-cluster-flags-t"><type>cairo_text_cluster_flags_t</type></link> *cluster_flags</parameter>);
<link linkend="cairo-font-face-t"><returnvalue>cairo_font_face_t</returnvalue></link> * <link linkend="cairo-scaled-font-get-font-face">cairo_scaled_font_get_font_face</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link> <link linkend="cairo-scaled-font-get-font-options">cairo_scaled_font_get_font_options</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> *options</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link> <link linkend="cairo-scaled-font-get-font-matrix">cairo_scaled_font_get_font_matrix</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *font_matrix</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link> <link linkend="cairo-scaled-font-get-ctm">cairo_scaled_font_get_ctm</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *ctm</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link> <link linkend="cairo-scaled-font-get-scale-matrix">cairo_scaled_font_get_scale_matrix</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *scale_matrix</parameter>);
<link linkend="cairo-font-type-t"><returnvalue>cairo_font_type_t</returnvalue></link> <link linkend="cairo-scaled-font-get-type">cairo_scaled_font_get_type</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);
unsigned <link linkend="int"><returnvalue>int</returnvalue></link> <link linkend="cairo-scaled-font-get-reference-count">cairo_scaled_font_get_reference_count</link>
(<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);
<link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> <link linkend="cairo-scaled-font-set-user-data">cairo_scaled_font_set_user_data</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</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-scaled-font-get-user-data">cairo_scaled_font_get_user_data</link> (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter>const <link linkend="cairo-user-data-key-t"><type>cairo_user_data_key_t</type></link> *key</parameter>);
</synopsis>
</refsynopsisdiv>
<refsect1 id="cairo-cairo-scaled-font-t.description" role="desc">
<title role="desc.title">Description</title>
<para>
<link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> represents a realization of a font face at a particular
size and transformation and a certain set of font options.
</para>
</refsect1>
<refsect1 id="cairo-cairo-scaled-font-t.details" role="details">
<title role="details.title">Details</title>
<refsect2 id="cairo-scaled-font-t" role="typedef">
<title>cairo_scaled_font_t</title>
<indexterm zone="cairo-scaled-font-t"><primary sortas="scaled_font_t">cairo_scaled_font_t</primary></indexterm>
<programlisting>typedef struct _cairo_scaled_font cairo_scaled_font_t;
</programlisting>
<para>
A <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> is a font scaled to a particular size and device
resolution. A <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> is most useful for low-level font
usage where a library or application wants to cache a reference
to a scaled font to speed up the computation of metrics.
</para>
<para>
There are various types of scaled fonts, depending on the
<firstterm>font backend</firstterm> they use. The type of a
scaled font can be queried using <link linkend="cairo-scaled-font-get-type"><function>cairo_scaled_font_get_type()</function></link>.
</para>
<para>
Memory management of <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> is done with
<link linkend="cairo-scaled-font-reference"><function>cairo_scaled_font_reference()</function></link> and <link linkend="cairo-scaled-font-destroy"><function>cairo_scaled_font_destroy()</function></link>.
</para></refsect2>
<refsect2 id="cairo-scaled-font-create" role="function">
<title>cairo_scaled_font_create ()</title>
<indexterm zone="cairo-scaled-font-create"><primary sortas="scaled_font_create">cairo_scaled_font_create</primary></indexterm>
<programlisting><link linkend="cairo-scaled-font-t"><returnvalue>cairo_scaled_font_t</returnvalue></link> * cairo_scaled_font_create (<parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>,
<parameter>const <link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *font_matrix</parameter>,
<parameter>const <link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *ctm</parameter>,
<parameter>const <link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> *options</parameter>);</programlisting>
<para>
Creates a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> object from a font face and matrices that
describe the size of the font and the environment in which it will
be used.
</para><variablelist role="params">
<varlistentry><term><parameter>font_face</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>font_matrix</parameter> :</term>
<listitem><simpara>font space to user space transformation matrix for the
font. In the simplest case of a N point font, this matrix is
just a scale by N, but it can also be used to shear the font
or stretch it unequally along the two axes. See
<link linkend="cairo-set-font-matrix"><function>cairo_set_font_matrix()</function></link>.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>ctm</parameter> :</term>
<listitem><simpara>user to device transformation matrix with which the font will
be used.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>options</parameter> :</term>
<listitem><simpara>options to use when getting metrics for the font and
rendering with it.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> a newly created <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>. Destroy with
<link linkend="cairo-scaled-font-destroy"><function>cairo_scaled_font_destroy()</function></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-scaled-font-reference" role="function">
<title>cairo_scaled_font_reference ()</title>
<indexterm zone="cairo-scaled-font-reference"><primary sortas="scaled_font_reference">cairo_scaled_font_reference</primary></indexterm>
<programlisting><link linkend="cairo-scaled-font-t"><returnvalue>cairo_scaled_font_t</returnvalue></link> * cairo_scaled_font_reference (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);</programlisting>
<para>
Increases the reference count on <parameter>scaled_font</parameter> by one. This prevents
<parameter>scaled_font</parameter> from being destroyed until a matching call to
<link linkend="cairo-scaled-font-destroy"><function>cairo_scaled_font_destroy()</function></link> is made.
</para>
<para>
The number of references to a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> can be get using
<link linkend="cairo-scaled-font-get-reference-count"><function>cairo_scaled_font_get_reference_count()</function></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>, (may be <link linkend="NULL:CAPS"><literal>NULL</literal></link> in which case
this function does nothing)
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the referenced <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-scaled-font-destroy" role="function">
<title>cairo_scaled_font_destroy ()</title>
<indexterm zone="cairo-scaled-font-destroy"><primary sortas="scaled_font_destroy">cairo_scaled_font_destroy</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> cairo_scaled_font_destroy (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);</programlisting>
<para>
Decreases the reference count on <parameter>font</parameter> by one. If the result
is zero, then <parameter>font</parameter> and all associated resources are freed.
See <link linkend="cairo-scaled-font-reference"><function>cairo_scaled_font_reference()</function></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-scaled-font-status" role="function">
<title>cairo_scaled_font_status ()</title>
<indexterm zone="cairo-scaled-font-status"><primary sortas="scaled_font_status">cairo_scaled_font_status</primary></indexterm>
<programlisting><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> cairo_scaled_font_status (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);</programlisting>
<para>
Checks whether an error has previously occurred for this
scaled_font.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link> or another error such as
<link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-font-extents-t" role="struct">
<title>cairo_font_extents_t</title>
<indexterm zone="cairo-font-extents-t"><primary sortas="font_extents_t">cairo_font_extents_t</primary></indexterm>
<programlisting>typedef struct {
double ascent;
double descent;
double height;
double max_x_advance;
double max_y_advance;
} cairo_font_extents_t;
</programlisting>
<para>
The <link linkend="cairo-font-extents-t"><type>cairo_font_extents_t</type></link> structure stores metric information for
a font. Values are given in the current user-space coordinate
system.
</para>
<para>
Because font metrics are in user-space coordinates, they are
mostly, but not entirely, independent of the current transformation
matrix. If you call <literal>cairo_scale(cr, 2.0, 2.0)</literal>,
text will be drawn twice as big, but the reported text extents will
not be doubled. They will change slightly due to hinting (so you
can't assume that metrics are independent of the transformation
matrix), but otherwise will remain unchanged.
</para><variablelist role="struct">
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-font-extents-t.ascent">ascent</structfield>;</term>
<listitem><simpara>the distance that the font extends above the baseline.
Note that this is not always exactly equal to the maximum
of the extents of all the glyphs in the font, but rather
is picked to express the font designer's intent as to
how the font should align with elements above it.
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-font-extents-t.descent">descent</structfield>;</term>
<listitem><simpara>the distance that the font extends below the baseline.
This value is positive for typical fonts that include
portions below the baseline. Note that this is not always
exactly equal to the maximum of the extents of all the
glyphs in the font, but rather is picked to express the
font designer's intent as to how the the font should
align with elements below it.
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-font-extents-t.height">height</structfield>;</term>
<listitem><simpara>the recommended vertical distance between baselines when
setting consecutive lines of text with the font. This
is greater than <parameter>ascent</parameter>+<parameter>descent</parameter> by a
quantity known as the <firstterm>line spacing</firstterm>
or <firstterm>external leading</firstterm>. When space
is at a premium, most fonts can be set with only
a distance of <parameter>ascent</parameter>+<parameter>descent</parameter> between lines.
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-font-extents-t.max-x-advance">max_x_advance</structfield>;</term>
<listitem><simpara>the maximum distance in the X direction that
the the origin is advanced for any glyph in the font.
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-font-extents-t.max-y-advance">max_y_advance</structfield>;</term>
<listitem><simpara>the maximum distance in the Y direction that
the the origin is advanced for any glyph in the font.
this will be zero for normal fonts used for horizontal
writing. (The scripts of East Asia are sometimes written
vertically.)
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-scaled-font-extents" role="function">
<title>cairo_scaled_font_extents ()</title>
<indexterm zone="cairo-scaled-font-extents"><primary sortas="scaled_font_extents">cairo_scaled_font_extents</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> cairo_scaled_font_extents (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-font-extents-t"><type>cairo_font_extents_t</type></link> *extents</parameter>);</programlisting>
<para>
Gets the metrics for a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>extents</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-font-extents-t"><type>cairo_font_extents_t</type></link> which to store the retrieved extents.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-text-extents-t" role="struct">
<title>cairo_text_extents_t</title>
<indexterm zone="cairo-text-extents-t"><primary sortas="text_extents_t">cairo_text_extents_t</primary></indexterm>
<programlisting>typedef struct {
double x_bearing;
double y_bearing;
double width;
double height;
double x_advance;
double y_advance;
} cairo_text_extents_t;
</programlisting>
<para>
The <link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> structure stores the extents of a single
glyph or a string of glyphs in user-space coordinates. Because text
extents are in user-space coordinates, they are mostly, but not
entirely, independent of the current transformation matrix. If you call
<literal>cairo_scale(cr, 2.0, 2.0)</literal>, text will
be drawn twice as big, but the reported text extents will not be
doubled. They will change slightly due to hinting (so you can't
assume that metrics are independent of the transformation matrix),
but otherwise will remain unchanged.
</para><variablelist role="struct">
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-text-extents-t.x-bearing">x_bearing</structfield>;</term>
<listitem><simpara>the horizontal distance from the origin to the
leftmost part of the glyphs as drawn. Positive if the
glyphs lie entirely to the right of the origin.
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-text-extents-t.y-bearing">y_bearing</structfield>;</term>
<listitem><simpara>the vertical distance from the origin to the
topmost part of the glyphs as drawn. Positive only if the
glyphs lie completely below the origin; will usually be
negative.
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-text-extents-t.width">width</structfield>;</term>
<listitem><simpara>width of the glyphs as drawn
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-text-extents-t.height">height</structfield>;</term>
<listitem><simpara>height of the glyphs as drawn
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-text-extents-t.x-advance">x_advance</structfield>;</term>
<listitem><simpara>distance to advance in the X direction
after drawing these glyphs
</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link> <structfield id="cairo-text-extents-t.y-advance">y_advance</structfield>;</term>
<listitem><simpara>distance to advance in the Y direction
after drawing these glyphs. Will typically be zero except
for vertical text layout as found in East-Asian languages.
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-scaled-font-text-extents" role="function" condition="since:1.2">
<title>cairo_scaled_font_text_extents ()</title>
<indexterm zone="cairo-scaled-font-text-extents" role="1.2"><primary sortas="scaled_font_text_extents">cairo_scaled_font_text_extents</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> cairo_scaled_font_text_extents (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter>const <link linkend="char"><type>char</type></link> *utf8</parameter>,
<parameter><link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> *extents</parameter>);</programlisting>
<para>
Gets the extents for a string of text. The extents describe a
user-space rectangle that encloses the "inked" portion of the text
drawn at the origin (0,0) (as it would be drawn by <link linkend="cairo-show-text"><function>cairo_show_text()</function></link>
if the cairo graphics state were set to the same font_face,
font_matrix, ctm, and font_options as <parameter>scaled_font</parameter>). Additionally,
the x_advance and y_advance values indicate the amount by which the
current point would be advanced by <link linkend="cairo-show-text"><function>cairo_show_text()</function></link>.
</para>
<para>
Note that whitespace characters do not directly contribute to the
size of the rectangle (extents.width and extents.height). They do
contribute indirectly by changing the position of non-whitespace
characters. In particular, trailing whitespace characters are
likely to not affect the size of the rectangle, though they will
affect the x_advance and y_advance values.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>utf8</parameter> :</term>
<listitem><simpara>a NUL-terminated string of text, encoded in UTF-8
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>extents</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> which to store the retrieved extents.
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-scaled-font-glyph-extents" role="function">
<title>cairo_scaled_font_glyph_extents ()</title>
<indexterm zone="cairo-scaled-font-glyph-extents"><primary sortas="scaled_font_glyph_extents">cairo_scaled_font_glyph_extents</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> cairo_scaled_font_glyph_extents (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter>const <link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link> *glyphs</parameter>,
<parameter><link linkend="int"><type>int</type></link> num_glyphs</parameter>,
<parameter><link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> *extents</parameter>);</programlisting>
<para>
Gets the extents for an array of glyphs. The extents describe a
user-space rectangle that encloses the "inked" portion of the
glyphs, (as they would be drawn by <link linkend="cairo-show-glyphs"><function>cairo_show_glyphs()</function></link> if the cairo
graphics state were set to the same font_face, font_matrix, ctm,
and font_options as <parameter>scaled_font</parameter>). Additionally, the x_advance and
y_advance values indicate the amount by which the current point
would be advanced by <link linkend="cairo-show-glyphs"><function>cairo_show_glyphs()</function></link>.
</para>
<para>
Note that whitespace glyphs do not contribute to the size of the
rectangle (extents.width and extents.height).
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>glyphs</parameter> :</term>
<listitem><simpara>an array of glyph IDs with X and Y offsets.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>num_glyphs</parameter> :</term>
<listitem><simpara>the number of glyphs in the <parameter>glyphs</parameter> array
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>extents</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> which to store the retrieved extents.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="cairo-scaled-font-text-to-glyphs" role="function" condition="since:1.8">
<title>cairo_scaled_font_text_to_glyphs ()</title>
<indexterm zone="cairo-scaled-font-text-to-glyphs" role="1.8"><primary sortas="scaled_font_text_to_glyphs">cairo_scaled_font_text_to_glyphs</primary></indexterm>
<programlisting><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> cairo_scaled_font_text_to_glyphs (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="double"><type>double</type></link> x</parameter>,
<parameter><link linkend="double"><type>double</type></link> y</parameter>,
<parameter>const <link linkend="char"><type>char</type></link> *utf8</parameter>,
<parameter><link linkend="int"><type>int</type></link> utf8_len</parameter>,
<parameter><link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link> **glyphs</parameter>,
<parameter><link linkend="int"><type>int</type></link> *num_glyphs</parameter>,
<parameter><link linkend="cairo-text-cluster-t"><type>cairo_text_cluster_t</type></link> **clusters</parameter>,
<parameter><link linkend="int"><type>int</type></link> *num_clusters</parameter>,
<parameter><link linkend="cairo-text-cluster-flags-t"><type>cairo_text_cluster_flags_t</type></link> *cluster_flags</parameter>);</programlisting>
<para>
Converts UTF-8 text to an array of glyphs, optionally with cluster
mapping, that can be used to render later using <parameter>scaled_font</parameter>.
</para>
<para>
If <parameter>glyphs</parameter> initially points to a non-<link linkend="NULL:CAPS"><literal>NULL</literal></link> value, that array is used
as a glyph buffer, and <parameter>num_glyphs</parameter> should point to the number of glyph
entries available there. If the provided glyph array is too short for
the conversion, a new glyph array is allocated using <link linkend="cairo-glyph-allocate"><function>cairo_glyph_allocate()</function></link>
and placed in <parameter>glyphs</parameter>. Upon return, <parameter>num_glyphs</parameter> always contains the
number of generated glyphs. If the value <parameter>glyphs</parameter> points to has changed
after the call, the user is responsible for freeing the allocated glyph
array using <link linkend="cairo-glyph-free"><function>cairo_glyph_free()</function></link>. This may happen even if the provided
array was large enough.
</para>
<para>
If <parameter>clusters</parameter> is not <link linkend="NULL:CAPS"><literal>NULL</literal></link>, <parameter>num_clusters</parameter> and <parameter>cluster_flags</parameter> should not be <link linkend="NULL:CAPS"><literal>NULL</literal></link>,
and cluster mapping will be computed.
The semantics of how cluster array allocation works is similar to the glyph
array. That is,
if <parameter>clusters</parameter> initially points to a non-<link linkend="NULL:CAPS"><literal>NULL</literal></link> value, that array is used
as a cluster buffer, and <parameter>num_clusters</parameter> should point to the number of cluster
entries available there. If the provided cluster array is too short for
the conversion, a new cluster array is allocated using <link linkend="cairo-text-cluster-allocate"><function>cairo_text_cluster_allocate()</function></link>
and placed in <parameter>clusters</parameter>. Upon return, <parameter>num_clusters</parameter> always contains the
number of generated clusters. If the value <parameter>clusters</parameter> points at has changed
after the call, the user is responsible for freeing the allocated cluster
array using <link linkend="cairo-text-cluster-free"><function>cairo_text_cluster_free()</function></link>. This may happen even if the provided
array was large enough.
</para>
<para>
In the simplest case, <parameter>glyphs</parameter> and <parameter>clusters</parameter> can point to <link linkend="NULL:CAPS"><literal>NULL</literal></link> initially
and a suitable array will be allocated. In code:
<informalexample><programlisting>
cairo_status_t status;
cairo_glyph_t *glyphs = NULL;
int num_glyphs;
cairo_text_cluster_t *clusters = NULL;
int num_clusters;
cairo_text_cluster_flags_t cluster_flags;
status = cairo_scaled_font_text_to_glyphs (scaled_font,
x, y,
utf8, utf8_len,
&glyphs, &num_glyphs,
&clusters, &num_clusters, &cluster_flags);
if (status == CAIRO_STATUS_SUCCESS) {
cairo_show_text_glyphs (cr,
utf8, utf8_len,
glyphs, num_glyphs,
clusters, num_clusters, cluster_flags);
cairo_glyph_free (glyphs);
cairo_text_cluster_free (clusters);
}
</programlisting></informalexample>
</para>
<para>
If no cluster mapping is needed:
<informalexample><programlisting>
cairo_status_t status;
cairo_glyph_t *glyphs = NULL;
int num_glyphs;
status = cairo_scaled_font_text_to_glyphs (scaled_font,
x, y,
utf8, utf8_len,
&glyphs, &num_glyphs,
NULL, NULL,
NULL);
if (status == CAIRO_STATUS_SUCCESS) {
cairo_show_glyphs (cr, glyphs, num_glyphs);
cairo_glyph_free (glyphs);
}
</programlisting></informalexample>
</para>
<para>
If stack-based glyph and cluster arrays are to be used for small
arrays:
<informalexample><programlisting>
cairo_status_t status;
cairo_glyph_t stack_glyphs[40];
cairo_glyph_t *glyphs = stack_glyphs;
int num_glyphs = sizeof (stack_glyphs) / sizeof (stack_glyphs[0]);
cairo_text_cluster_t stack_clusters[40];
cairo_text_cluster_t *clusters = stack_clusters;
int num_clusters = sizeof (stack_clusters) / sizeof (stack_clusters[0]);
cairo_text_cluster_flags_t cluster_flags;
status = cairo_scaled_font_text_to_glyphs (scaled_font,
x, y,
utf8, utf8_len,
&glyphs, &num_glyphs,
&clusters, &num_clusters, &cluster_flags);
if (status == CAIRO_STATUS_SUCCESS) {
cairo_show_text_glyphs (cr,
utf8, utf8_len,
glyphs, num_glyphs,
clusters, num_clusters, cluster_flags);
if (glyphs != stack_glyphs)
cairo_glyph_free (glyphs);
if (clusters != stack_clusters)
cairo_text_cluster_free (clusters);
}
</programlisting></informalexample>
</para>
<para>
For details of how <parameter>clusters</parameter>, <parameter>num_clusters</parameter>, and <parameter>cluster_flags</parameter> map input
UTF-8 text to the output glyphs see <link linkend="cairo-show-text-glyphs"><function>cairo_show_text_glyphs()</function></link>.
</para>
<para>
The output values can be readily passed to <link linkend="cairo-show-text-glyphs"><function>cairo_show_text_glyphs()</function></link>
<link linkend="cairo-show-glyphs"><function>cairo_show_glyphs()</function></link>, or related functions, assuming that the exact
same <parameter>scaled_font</parameter> is used for the operation.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>x</parameter> :</term>
<listitem><simpara>X position to place first glyph
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>y</parameter> :</term>
<listitem><simpara>Y position to place first glyph
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>utf8</parameter> :</term>
<listitem><simpara>a string of text encoded in UTF-8
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>utf8_len</parameter> :</term>
<listitem><simpara>length of <parameter>utf8</parameter> in bytes, or -1 if it is NUL-terminated
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>glyphs</parameter> :</term>
<listitem><simpara>pointer to array of glyphs to fill
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>num_glyphs</parameter> :</term>
<listitem><simpara>pointer to number of glyphs
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>clusters</parameter> :</term>
<listitem><simpara>pointer to array of cluster mapping information to fill, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>num_clusters</parameter> :</term>
<listitem><simpara>pointer to number of clusters, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>cluster_flags</parameter> :</term>
<listitem><simpara>pointer to location to store cluster flags corresponding to the
output <parameter>clusters</parameter>, or <link linkend="NULL:CAPS"><literal>NULL</literal></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link> upon success, or an error status
if the input values are wrong or if conversion failed. If the input
values are correct but the conversion failed, the error status is also
set on <parameter>scaled_font</parameter>.
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-scaled-font-get-font-face" role="function" condition="since:1.2">
<title>cairo_scaled_font_get_font_face ()</title>
<indexterm zone="cairo-scaled-font-get-font-face" role="1.2"><primary sortas="scaled_font_get_font_face">cairo_scaled_font_get_font_face</primary></indexterm>
<programlisting><link linkend="cairo-font-face-t"><returnvalue>cairo_font_face_t</returnvalue></link> * cairo_scaled_font_get_font_face (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);</programlisting>
<para>
Gets the font face that this scaled font uses. This is the
font face passed to <link linkend="cairo-scaled-font-create"><function>cairo_scaled_font_create()</function></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> The <link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> with which <parameter>scaled_font</parameter> was
created.
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-scaled-font-get-font-options" role="function" condition="since:1.2">
<title>cairo_scaled_font_get_font_options ()</title>
<indexterm zone="cairo-scaled-font-get-font-options" role="1.2"><primary sortas="scaled_font_get_font_options">cairo_scaled_font_get_font_options</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> cairo_scaled_font_get_font_options (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> *options</parameter>);</programlisting>
<para>
Stores the font options with which <parameter>scaled_font</parameter> was created into
<parameter>options</parameter>.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>options</parameter> :</term>
<listitem><simpara>return value for the font options
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-scaled-font-get-font-matrix" role="function" condition="since:1.2">
<title>cairo_scaled_font_get_font_matrix ()</title>
<indexterm zone="cairo-scaled-font-get-font-matrix" role="1.2"><primary sortas="scaled_font_get_font_matrix">cairo_scaled_font_get_font_matrix</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> cairo_scaled_font_get_font_matrix (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *font_matrix</parameter>);</programlisting>
<para>
Stores the font matrix with which <parameter>scaled_font</parameter> was created into
<parameter>matrix</parameter>.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>font_matrix</parameter> :</term>
<listitem><simpara>return value for the matrix
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-scaled-font-get-ctm" role="function" condition="since:1.2">
<title>cairo_scaled_font_get_ctm ()</title>
<indexterm zone="cairo-scaled-font-get-ctm" role="1.2"><primary sortas="scaled_font_get_ctm">cairo_scaled_font_get_ctm</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> cairo_scaled_font_get_ctm (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *ctm</parameter>);</programlisting>
<para>
Stores the CTM with which <parameter>scaled_font</parameter> was created into <parameter>ctm</parameter>.
Note that the translation offsets (x0, y0) of the CTM are ignored
by <link linkend="cairo-scaled-font-create"><function>cairo_scaled_font_create()</function></link>. So, the matrix this
function returns always has 0,0 as x0,y0.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>ctm</parameter> :</term>
<listitem><simpara>return value for the CTM
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-scaled-font-get-scale-matrix" role="function" condition="since:1.8">
<title>cairo_scaled_font_get_scale_matrix ()</title>
<indexterm zone="cairo-scaled-font-get-scale-matrix" role="1.8"><primary sortas="scaled_font_get_scale_matrix">cairo_scaled_font_get_scale_matrix</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> cairo_scaled_font_get_scale_matrix (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>,
<parameter><link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *scale_matrix</parameter>);</programlisting>
<para>
Stores the scale matrix of <parameter>scaled_font</parameter> into <parameter>matrix</parameter>.
The scale matrix is product of the font matrix and the ctm
associated with the scaled font, and hence is the matrix mapping from
font space to device space.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>scale_matrix</parameter> :</term>
<listitem><simpara>return value for the matrix
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-scaled-font-get-type" role="function" condition="since:1.2">
<title>cairo_scaled_font_get_type ()</title>
<indexterm zone="cairo-scaled-font-get-type" role="1.2"><primary sortas="scaled_font_get_type">cairo_scaled_font_get_type</primary></indexterm>
<programlisting><link linkend="cairo-font-type-t"><returnvalue>cairo_font_type_t</returnvalue></link> cairo_scaled_font_get_type (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);</programlisting>
<para>
This function returns the type of the backend used to create
a scaled font. See <link linkend="cairo-font-type-t"><type>cairo_font_type_t</type></link> for available types.
However, this function never returns <link linkend="CAIRO-FONT-TYPE-TOY:CAPS"><literal>CAIRO_FONT_TYPE_TOY</literal></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> The type of <parameter>scaled_font</parameter>.
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-scaled-font-get-reference-count" role="function" condition="since:1.4">
<title>cairo_scaled_font_get_reference_count ()</title>
<indexterm zone="cairo-scaled-font-get-reference-count" role="1.4"><primary sortas="scaled_font_get_reference_count">cairo_scaled_font_get_reference_count</primary></indexterm>
<programlisting>unsigned <link linkend="int"><returnvalue>int</returnvalue></link> cairo_scaled_font_get_reference_count
(<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);</programlisting>
<para>
Returns the current reference count of <parameter>scaled_font</parameter>.
</para><variablelist role="params">
<varlistentry><term><parameter>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the current reference count of <parameter>scaled_font</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-scaled-font-set-user-data" role="function" condition="since:1.4">
<title>cairo_scaled_font_set_user_data ()</title>
<indexterm zone="cairo-scaled-font-set-user-data" role="1.4"><primary sortas="scaled_font_set_user_data">cairo_scaled_font_set_user_data</primary></indexterm>
<programlisting><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> cairo_scaled_font_set_user_data (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</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>scaled_font</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>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>key</parameter> :</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> :</term>
<listitem><simpara>the user data to attach to the <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>destroy</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-destroy-func-t"><type>cairo_destroy_func_t</type></link> which will be called when the
<link linkend="cairo-t"><type>cairo_t</type></link> is destroyed or when new user data is attached using the
same key.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</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 1.4</para></refsect2>
<refsect2 id="cairo-scaled-font-get-user-data" role="function" condition="since:1.4">
<title>cairo_scaled_font_get_user_data ()</title>
<indexterm zone="cairo-scaled-font-get-user-data" role="1.4"><primary sortas="scaled_font_get_user_data">cairo_scaled_font_get_user_data</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link> * cairo_scaled_font_get_user_data (<parameter><link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</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>scaled_font</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>scaled_font</parameter> :</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>key</parameter> :</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> :</term><listitem><simpara> the user data previously attached or <link linkend="NULL:CAPS"><literal>NULL</literal></link>.
</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.4</para></refsect2>
</refsect1>
<refsect1 id="cairo-cairo-scaled-font-t.see-also">
<title>See Also</title>
<link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link>, <link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link>, <link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link>
</refsect1>
</refentry>