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<refentry id="cairo-text">
<refmeta>
<refentrytitle role="top_of_page" id="cairo-text.top_of_page">text</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>
  CAIRO Library
</refmiscinfo>
</refmeta>
<refnamediv>
<refname>text</refname>
<refpurpose>Rendering text and glyphs</refpurpose>
</refnamediv>

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

<synopsis>                    <link linkend="cairo-glyph-t">cairo_glyph_t</link>;
enum                <link linkend="cairo-font-slant-t">cairo_font_slant_t</link>;
enum                <link linkend="cairo-font-weight-t">cairo_font_weight_t</link>;
                    <link linkend="cairo-text-cluster-t">cairo_text_cluster_t</link>;
enum                <link linkend="cairo-text-cluster-flags-t">cairo_text_cluster_flags_t</link>;
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-select-font-face">cairo_select_font_face</link>              (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="char"><type>char</type></link> *family</parameter>,
                                                         <parameter><link linkend="cairo-font-slant-t"><type>cairo_font_slant_t</type></link> slant</parameter>,
                                                         <parameter><link linkend="cairo-font-weight-t"><type>cairo_font_weight_t</type></link> weight</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-set-font-size">cairo_set_font_size</link>                 (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="double"><type>double</type></link> size</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-set-font-matrix">cairo_set_font_matrix</link>               (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *matrix</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-get-font-matrix">cairo_get_font_matrix</link>               (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *matrix</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-set-font-options">cairo_set_font_options</link>              (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <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-get-font-options">cairo_get_font_options</link>              (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</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-set-font-face">cairo_set_font_face</link>                 (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>);
<link linkend="cairo-font-face-t"><returnvalue>cairo_font_face_t</returnvalue></link> * <link linkend="cairo-get-font-face">cairo_get_font_face</link>                 (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-set-scaled-font">cairo_set_scaled_font</link>               (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);
<link linkend="cairo-scaled-font-t"><returnvalue>cairo_scaled_font_t</returnvalue></link> * <link linkend="cairo-get-scaled-font">cairo_get_scaled_font</link>             (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-show-text">cairo_show_text</link>                     (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="char"><type>char</type></link> *utf8</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-show-glyphs">cairo_show_glyphs</link>                   (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</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>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-show-text-glyphs">cairo_show_text_glyphs</link>              (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="char"><type>char</type></link> *utf8</parameter>,
                                                         <parameter><link linkend="int"><type>int</type></link> utf8_len</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>const <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="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-font-extents">cairo_font_extents</link>                  (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="cairo-font-extents-t"><type>cairo_font_extents_t</type></link> *extents</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-text-extents">cairo_text_extents</link>                  (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</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-glyph-extents">cairo_glyph_extents</link>                 (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</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-font-face-t"><returnvalue>cairo_font_face_t</returnvalue></link> * <link linkend="cairo-toy-font-face-create">cairo_toy_font_face_create</link>          (<parameter>const <link linkend="char"><type>char</type></link> *family</parameter>,
                                                         <parameter><link linkend="cairo-font-slant-t"><type>cairo_font_slant_t</type></link> slant</parameter>,
                                                         <parameter><link linkend="cairo-font-weight-t"><type>cairo_font_weight_t</type></link> weight</parameter>);
const <link linkend="char"><returnvalue>char</returnvalue></link> *        <link linkend="cairo-toy-font-face-get-family">cairo_toy_font_face_get_family</link>      (<parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>);
<link linkend="cairo-font-slant-t"><returnvalue>cairo_font_slant_t</returnvalue></link>  <link linkend="cairo-toy-font-face-get-slant">cairo_toy_font_face_get_slant</link>       (<parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>);
<link linkend="cairo-font-weight-t"><returnvalue>cairo_font_weight_t</returnvalue></link> <link linkend="cairo-toy-font-face-get-weight">cairo_toy_font_face_get_weight</link>      (<parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>);
<link linkend="cairo-glyph-t"><returnvalue>cairo_glyph_t</returnvalue></link> *     <link linkend="cairo-glyph-allocate">cairo_glyph_allocate</link>                (<parameter><link linkend="int"><type>int</type></link> num_glyphs</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-glyph-free">cairo_glyph_free</link>                    (<parameter><link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link> *glyphs</parameter>);
<link linkend="cairo-text-cluster-t"><returnvalue>cairo_text_cluster_t</returnvalue></link> * <link linkend="cairo-text-cluster-allocate">cairo_text_cluster_allocate</link>      (<parameter><link linkend="int"><type>int</type></link> num_clusters</parameter>);
<link linkend="void"><returnvalue>void</returnvalue></link>                <link linkend="cairo-text-cluster-free">cairo_text_cluster_free</link>             (<parameter><link linkend="cairo-text-cluster-t"><type>cairo_text_cluster_t</type></link> *clusters</parameter>);
</synopsis>
</refsynopsisdiv>

<refsect1 id="cairo-text.description" role="desc">
<title role="desc.title">Description</title>
<para>
The functions with <emphasis>text</emphasis> in their name form cairo's
<firstterm>toy</firstterm> text API.  The toy API takes UTF-8 encoded
text and is limited in its functionality to rendering simple
left-to-right text with no advanced features.  That means for example
that most complex scripts like Hebrew, Arabic, and Indic scripts are
out of question.  No kerning or correct positioning of diacritical marks
either.  The font selection is pretty limited too and doesn't handle the
case that the selected font does not cover the characters in the text.
This set of functions are really that, a toy text API, for testing and
demonstration purposes.  Any serious application should avoid them.
</para>
<para>
The functions with <emphasis>glyphs</emphasis> in their name form cairo's
<firstterm>low-level</firstterm> text API.  The low-level API relies on
the user to convert text to a set of glyph indexes and positions.  This
is a very hard problem and is best handled by external libraries, like
the pangocairo that is part of the Pango text layout and rendering library.
Pango is available from <ulink
url="http://www.pango.org/">http://www.pango.org/</ulink>.
</para>
</refsect1>
<refsect1 id="cairo-text.details" role="details">
<title role="details.title">Details</title>
<refsect2 id="cairo-glyph-t" role="struct" condition="since:1.0">
<title>cairo_glyph_t</title>
<indexterm zone="cairo-glyph-t" role="1.0"><primary sortas="glyph_t">cairo_glyph_t</primary></indexterm>
<programlisting>typedef struct {
    unsigned long        index;
    double               x;
    double               y;
} cairo_glyph_t;
</programlisting>
<para>
The <link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link> structure holds information about a single glyph
when drawing or measuring text. A font is (in simple terms) a
collection of shapes used to draw text. A glyph is one of these
shapes. There can be multiple glyphs for a single character
(alternates to be used in different contexts, for example), or a
glyph can be a <firstterm>ligature</firstterm> of multiple
characters. Cairo doesn't expose any way of converting input text
into glyphs, so in order to use the Cairo interfaces that take
arrays of glyphs, you must directly access the appropriate
underlying font system.
</para>
<para>
Note that the offsets given by <parameter>x</parameter> and <parameter>y</parameter> are not cumulative. When
drawing or measuring text, each glyph is individually positioned
with respect to the overall origin
</para><variablelist role="struct">
<varlistentry><term>unsigned&#160;<link linkend="long"><type>long</type></link>&#160;<structfield id="cairo-glyph-t.index">index</structfield>;</term>
<listitem><simpara>glyph index in the font. The exact interpretation of the
glyph index depends on the font technology being used.</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link>&#160;<structfield id="cairo-glyph-t.x">x</structfield>;</term>
<listitem><simpara>the offset in the X direction between the origin used for
drawing or measuring the string and the origin of this glyph.</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="double"><type>double</type></link>&#160;<structfield id="cairo-glyph-t.y">y</structfield>;</term>
<listitem><simpara>the offset in the Y direction between the origin used for
drawing or measuring the string and the origin of this glyph.</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-font-slant-t" role="enum" condition="since:1.0">
<title>enum cairo_font_slant_t</title>
<indexterm zone="cairo-font-slant-t" role="1.0"><primary sortas="font_slant_t">cairo_font_slant_t</primary></indexterm>
<programlisting>typedef enum {
    CAIRO_FONT_SLANT_NORMAL,
    CAIRO_FONT_SLANT_ITALIC,
    CAIRO_FONT_SLANT_OBLIQUE
} cairo_font_slant_t;
</programlisting>
<para>
Specifies variants of a font face based on their slant.
</para><variablelist role="enum">
<varlistentry id="CAIRO-FONT-SLANT-NORMAL:CAPS" role="constant">
<term><literal>CAIRO_FONT_SLANT_NORMAL</literal></term>
<listitem><simpara>Upright font style, since 1.0
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-FONT-SLANT-ITALIC:CAPS" role="constant">
<term><literal>CAIRO_FONT_SLANT_ITALIC</literal></term>
<listitem><simpara>Italic font style, since 1.0
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-FONT-SLANT-OBLIQUE:CAPS" role="constant">
<term><literal>CAIRO_FONT_SLANT_OBLIQUE</literal></term>
<listitem><simpara>Oblique font style, since 1.0
</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-font-weight-t" role="enum" condition="since:1.0">
<title>enum cairo_font_weight_t</title>
<indexterm zone="cairo-font-weight-t" role="1.0"><primary sortas="font_weight_t">cairo_font_weight_t</primary></indexterm>
<programlisting>typedef enum {
    CAIRO_FONT_WEIGHT_NORMAL,
    CAIRO_FONT_WEIGHT_BOLD
} cairo_font_weight_t;
</programlisting>
<para>
Specifies variants of a font face based on their weight.
</para><variablelist role="enum">
<varlistentry id="CAIRO-FONT-WEIGHT-NORMAL:CAPS" role="constant">
<term><literal>CAIRO_FONT_WEIGHT_NORMAL</literal></term>
<listitem><simpara>Normal font weight, since 1.0
</simpara></listitem>
</varlistentry>
<varlistentry id="CAIRO-FONT-WEIGHT-BOLD:CAPS" role="constant">
<term><literal>CAIRO_FONT_WEIGHT_BOLD</literal></term>
<listitem><simpara>Bold font weight, since 1.0
</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-text-cluster-t" role="struct" condition="since:1.8">
<title>cairo_text_cluster_t</title>
<indexterm zone="cairo-text-cluster-t" role="1.8"><primary sortas="text_cluster_t">cairo_text_cluster_t</primary></indexterm>
<programlisting>typedef struct {
    int        num_bytes;
    int        num_glyphs;
} cairo_text_cluster_t;
</programlisting>
<para>
The <link linkend="cairo-text-cluster-t"><type>cairo_text_cluster_t</type></link> structure holds information about a single
<firstterm>text cluster</firstterm>.  A text cluster is a minimal
mapping of some glyphs corresponding to some UTF-8 text.
</para>
<para>
For a cluster to be valid, both <parameter>num_bytes</parameter> and <parameter>num_glyphs</parameter> should
be non-negative, and at least one should be non-zero.
Note that clusters with zero glyphs are not as well supported as
normal clusters.  For example, PDF rendering applications typically
ignore those clusters when PDF text is being selected.
</para>
<para>
See <link linkend="cairo-show-text-glyphs"><function>cairo_show_text_glyphs()</function></link> for how clusters are used in advanced
text operations.
</para><variablelist role="struct">
<varlistentry><term><link linkend="int"><type>int</type></link>&#160;<structfield id="cairo-text-cluster-t.num-bytes">num_bytes</structfield>;</term>
<listitem><simpara>the number of bytes of UTF-8 text covered by cluster</simpara></listitem>
</varlistentry>
<varlistentry><term><link linkend="int"><type>int</type></link>&#160;<structfield id="cairo-text-cluster-t.num-glyphs">num_glyphs</structfield>;</term>
<listitem><simpara>the number of glyphs covered by cluster</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-text-cluster-flags-t" role="enum" condition="since:1.8">
<title>enum cairo_text_cluster_flags_t</title>
<indexterm zone="cairo-text-cluster-flags-t" role="1.8"><primary sortas="text_cluster_flags_t">cairo_text_cluster_flags_t</primary></indexterm>
<programlisting>typedef enum {
    CAIRO_TEXT_CLUSTER_FLAG_BACKWARD = 0x00000001
} cairo_text_cluster_flags_t;
</programlisting>
<para>
Specifies properties of a text cluster mapping.
</para><variablelist role="enum">
<varlistentry id="CAIRO-TEXT-CLUSTER-FLAG-BACKWARD:CAPS" role="constant">
<term><literal>CAIRO_TEXT_CLUSTER_FLAG_BACKWARD</literal></term>
<listitem><simpara>The clusters in the cluster array
map to glyphs in the glyph array from end to start. (Since 1.8)
</simpara></listitem>
</varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-select-font-face" role="function" condition="since:1.0">
<title>cairo_select_font_face ()</title>
<indexterm zone="cairo-select-font-face" role="1.0"><primary sortas="select_font_face">cairo_select_font_face</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_select_font_face              (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="char"><type>char</type></link> *family</parameter>,
                                                         <parameter><link linkend="cairo-font-slant-t"><type>cairo_font_slant_t</type></link> slant</parameter>,
                                                         <parameter><link linkend="cairo-font-weight-t"><type>cairo_font_weight_t</type></link> weight</parameter>);</programlisting>
<para>
Note: The <link linkend="cairo-select-font-face"><function>cairo_select_font_face()</function></link> function call is part of what
the cairo designers call the "toy" text API. It is convenient for
short demos and simple programs, but it is not expected to be
adequate for serious text-using applications.
</para>
<para>
Selects a family and style of font from a simplified description as
a family name, slant and weight. Cairo provides no operation to
list available family names on the system (this is a "toy",
remember), but the standard CSS2 generic family names, ("serif",
"sans-serif", "cursive", "fantasy", "monospace"), are likely to
work as expected.
</para>
<para>
If <parameter>family</parameter> starts with the string "<parameter>cairo</parameter>:", or if no native font
backends are compiled in, cairo will use an internal font family.
The internal font family recognizes many modifiers in the <parameter>family</parameter>
string, most notably, it recognizes the string "monospace".  That is,
the family name "<parameter>cairo</parameter>:monospace" will use the monospace version of
the internal font family.
</para>
<para>
For "real" font selection, see the font-backend-specific
font_face_create functions for the font backend you are using. (For
example, if you are using the freetype-based cairo-ft font backend,
see <link linkend="cairo-ft-font-face-create-for-ft-face"><function>cairo_ft_font_face_create_for_ft_face()</function></link> or
<link linkend="cairo-ft-font-face-create-for-pattern"><function>cairo_ft_font_face_create_for_pattern()</function></link>.) The resulting font face
could then be used with <link linkend="cairo-scaled-font-create"><function>cairo_scaled_font_create()</function></link> and
<link linkend="cairo-set-scaled-font"><function>cairo_set_scaled_font()</function></link>.
</para>
<para>
Similarly, when using the "real" font support, you can call
directly into the underlying font system, (such as fontconfig or
freetype), for operations such as listing available fonts, etc.
</para>
<para>
It is expected that most applications will need to use a more
comprehensive font handling and text layout library, (for example,
pango), in conjunction with cairo.
</para>
<para>
If text is drawn without a call to <link linkend="cairo-select-font-face"><function>cairo_select_font_face()</function></link>, (nor
<link linkend="cairo-set-font-face"><function>cairo_set_font_face()</function></link> nor <link linkend="cairo-set-scaled-font"><function>cairo_set_scaled_font()</function></link>), the default
family is platform-specific, but is essentially "sans-serif".
Default slant is <link linkend="CAIRO-FONT-SLANT-NORMAL:CAPS"><literal>CAIRO_FONT_SLANT_NORMAL</literal></link>, and default weight is
<link linkend="CAIRO-FONT-WEIGHT-NORMAL:CAPS"><literal>CAIRO_FONT_WEIGHT_NORMAL</literal></link>.
</para>
<para>
This function is equivalent to a call to <link linkend="cairo-toy-font-face-create"><function>cairo_toy_font_face_create()</function></link>
followed by <link linkend="cairo-set-font-face"><function>cairo_set_font_face()</function></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>family</parameter>&#160;:</term>
<listitem><simpara>a font family name, encoded in UTF-8</simpara></listitem></varlistentry>
<varlistentry><term><parameter>slant</parameter>&#160;:</term>
<listitem><simpara>the slant for the font</simpara></listitem></varlistentry>
<varlistentry><term><parameter>weight</parameter>&#160;:</term>
<listitem><simpara>the weight for the font</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-set-font-size" role="function" condition="since:1.0">
<title>cairo_set_font_size ()</title>
<indexterm zone="cairo-set-font-size" role="1.0"><primary sortas="set_font_size">cairo_set_font_size</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_set_font_size                 (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="double"><type>double</type></link> size</parameter>);</programlisting>
<para>
Sets the current font matrix to a scale by a factor of <parameter>size</parameter>, replacing
any font matrix previously set with <link linkend="cairo-set-font-size"><function>cairo_set_font_size()</function></link> or
<link linkend="cairo-set-font-matrix"><function>cairo_set_font_matrix()</function></link>. This results in a font size of <parameter>size</parameter> user space
units. (More precisely, this matrix will result in the font's
em-square being a <parameter>size</parameter> by <parameter>size</parameter> square in user space.)
</para>
<para>
If text is drawn without a call to <link linkend="cairo-set-font-size"><function>cairo_set_font_size()</function></link>, (nor
<link linkend="cairo-set-font-matrix"><function>cairo_set_font_matrix()</function></link> nor <link linkend="cairo-set-scaled-font"><function>cairo_set_scaled_font()</function></link>), the default
font size is 10.0.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>size</parameter>&#160;:</term>
<listitem><simpara>the new font size, in user space units</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-set-font-matrix" role="function" condition="since:1.0">
<title>cairo_set_font_matrix ()</title>
<indexterm zone="cairo-set-font-matrix" role="1.0"><primary sortas="set_font_matrix">cairo_set_font_matrix</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_set_font_matrix               (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *matrix</parameter>);</programlisting>
<para>
Sets the current font matrix to <parameter>matrix</parameter>. The font matrix gives a
transformation from the design space of the font (in this space,
the em-square is 1 unit by 1 unit) to user space. Normally, a
simple scale is used (see <link linkend="cairo-set-font-size"><function>cairo_set_font_size()</function></link>), but a more
complex font matrix can be used to shear the font
or stretch it unequally along the two axes
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>matrix</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> describing a transform to be applied to
the current font.</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-get-font-matrix" role="function" condition="since:1.0">
<title>cairo_get_font_matrix ()</title>
<indexterm zone="cairo-get-font-matrix" role="1.0"><primary sortas="get_font_matrix">cairo_get_font_matrix</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_get_font_matrix               (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="cairo-matrix-t"><type>cairo_matrix_t</type></link> *matrix</parameter>);</programlisting>
<para>
Stores the current font matrix into <parameter>matrix</parameter>. See
<link linkend="cairo-set-font-matrix"><function>cairo_set_font_matrix()</function></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>matrix</parameter>&#160;:</term>
<listitem><simpara>return value for the matrix</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-set-font-options" role="function" condition="since:1.0">
<title>cairo_set_font_options ()</title>
<indexterm zone="cairo-set-font-options" role="1.0"><primary sortas="set_font_options">cairo_set_font_options</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_set_font_options              (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> *options</parameter>);</programlisting>
<para>
Sets a set of custom font rendering options for the <link linkend="cairo-t"><type>cairo_t</type></link>.
Rendering options are derived by merging these options with the
options derived from underlying surface; if the value in <parameter>options</parameter>
has a default value (like <link linkend="CAIRO-ANTIALIAS-DEFAULT:CAPS"><literal>CAIRO_ANTIALIAS_DEFAULT</literal></link>), then the value
from the surface is used.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>options</parameter>&#160;:</term>
<listitem><simpara>font options to use</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-get-font-options" role="function" condition="since:1.0">
<title>cairo_get_font_options ()</title>
<indexterm zone="cairo-get-font-options" role="1.0"><primary sortas="get_font_options">cairo_get_font_options</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_get_font_options              (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> *options</parameter>);</programlisting>
<para>
Retrieves font rendering options set via <link linkend="cairo-set-font-options"><type>cairo_set_font_options</type></link>.
Note that the returned options do not include any options derived
from the underlying surface; they are literally the options
passed to <link linkend="cairo-set-font-options"><function>cairo_set_font_options()</function></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>options</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-font-options-t"><type>cairo_font_options_t</type></link> object into which to store
the retrieved options. All existing values are overwritten</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-set-font-face" role="function" condition="since:1.0">
<title>cairo_set_font_face ()</title>
<indexterm zone="cairo-set-font-face" role="1.0"><primary sortas="set_font_face">cairo_set_font_face</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_set_font_face                 (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>);</programlisting>
<para>
Replaces the current <link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> object in the <link linkend="cairo-t"><type>cairo_t</type></link> with
<parameter>font_face</parameter>. The replaced font face in the <link linkend="cairo-t"><type>cairo_t</type></link> will be
destroyed if there are no other references to it.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>font_face</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link>, or <link linkend="NULL:CAPS"><literal>NULL</literal></link> to restore to the default font</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-get-font-face" role="function" condition="since:1.0">
<title>cairo_get_font_face ()</title>
<indexterm zone="cairo-get-font-face" role="1.0"><primary sortas="get_font_face">cairo_get_font_face</primary></indexterm>
<programlisting><link linkend="cairo-font-face-t"><returnvalue>cairo_font_face_t</returnvalue></link> * cairo_get_font_face                 (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>);</programlisting>
<para>
Gets the current font face for a <link linkend="cairo-t"><type>cairo_t</type></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara>the current font face.  This object is owned by
cairo. To keep a reference to it, you must call
<link linkend="cairo-font-face-reference"><function>cairo_font_face_reference()</function></link>.
This function never returns <link linkend="NULL:CAPS"><literal>NULL</literal></link>. If memory cannot be allocated, a
special "nil" <link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> object will be returned on which
<link linkend="cairo-font-face-status"><function>cairo_font_face_status()</function></link> returns <link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link>. Using
this nil object will cause its error state to propagate to other
objects it is passed to, (for example, calling
<link linkend="cairo-set-font-face"><function>cairo_set_font_face()</function></link> with a nil font will trigger an error that
will shutdown the <link linkend="cairo-t"><type>cairo_t</type></link> object).</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-set-scaled-font" role="function" condition="since:1.2">
<title>cairo_set_scaled_font ()</title>
<indexterm zone="cairo-set-scaled-font" role="1.2"><primary sortas="set_scaled_font">cairo_set_scaled_font</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_set_scaled_font               (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> *scaled_font</parameter>);</programlisting>
<para>
Replaces the current font face, font matrix, and font options in
the <link linkend="cairo-t"><type>cairo_t</type></link> with those of the <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>.  Except for
some translation, the current CTM of the <link linkend="cairo-t"><type>cairo_t</type></link> should be the
same as that of the <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>, which can be accessed
using <link linkend="cairo-scaled-font-get-ctm"><function>cairo_scaled_font_get_ctm()</function></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>scaled_font</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link></simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.2</para></refsect2>
<refsect2 id="cairo-get-scaled-font" role="function" condition="since:1.4">
<title>cairo_get_scaled_font ()</title>
<indexterm zone="cairo-get-scaled-font" role="1.4"><primary sortas="get_scaled_font">cairo_get_scaled_font</primary></indexterm>
<programlisting><link linkend="cairo-scaled-font-t"><returnvalue>cairo_scaled_font_t</returnvalue></link> * cairo_get_scaled_font             (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>);</programlisting>
<para>
Gets the current scaled font for a <link linkend="cairo-t"><type>cairo_t</type></link>.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara>the current scaled font. This object is owned by
cairo. To keep a reference to it, you must call
<link linkend="cairo-scaled-font-reference"><function>cairo_scaled_font_reference()</function></link>.
This function never returns <link linkend="NULL:CAPS"><literal>NULL</literal></link>. If memory cannot be allocated, a
special "nil" <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link> object will be returned on which
<link linkend="cairo-scaled-font-status"><function>cairo_scaled_font_status()</function></link> returns <link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link>. Using
this nil object will cause its error state to propagate to other
objects it is passed to, (for example, calling
<link linkend="cairo-set-scaled-font"><function>cairo_set_scaled_font()</function></link> with a nil font will trigger an error that
will shutdown the <link linkend="cairo-t"><type>cairo_t</type></link> object).</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.4</para></refsect2>
<refsect2 id="cairo-show-text" role="function" condition="since:1.0">
<title>cairo_show_text ()</title>
<indexterm zone="cairo-show-text" role="1.0"><primary sortas="show_text">cairo_show_text</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_show_text                     (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="char"><type>char</type></link> *utf8</parameter>);</programlisting>
<para>
A drawing operator that generates the shape from a string of UTF-8
characters, rendered according to the current font_face, font_size
(font_matrix), and font_options.
</para>
<para>
This function first computes a set of glyphs for the string of
text. The first glyph is placed so that its origin is at the
current point. The origin of each subsequent glyph is offset from
that of the previous glyph by the advance values of the previous
glyph.
</para>
<para>
After this call the current point is moved to the origin of where
the next glyph would be placed in this same progression. That is,
the current point will be at the origin of the final glyph offset
by its advance values. This allows for easy display of a single
logical string with multiple calls to <link linkend="cairo-show-text"><function>cairo_show_text()</function></link>.
</para>
<para>
Note: The <link linkend="cairo-show-text"><function>cairo_show_text()</function></link> function call is part of what the cairo
designers call the "toy" text API. It is convenient for short demos
and simple programs, but it is not expected to be adequate for
serious text-using applications. See <link linkend="cairo-show-glyphs"><function>cairo_show_glyphs()</function></link> for the
"real" text display API in cairo.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a cairo context</simpara></listitem></varlistentry>
<varlistentry><term><parameter>utf8</parameter>&#160;:</term>
<listitem><simpara>a NUL-terminated string of text encoded in UTF-8, or <link linkend="NULL:CAPS"><literal>NULL</literal></link></simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-show-glyphs" role="function" condition="since:1.0">
<title>cairo_show_glyphs ()</title>
<indexterm zone="cairo-show-glyphs" role="1.0"><primary sortas="show_glyphs">cairo_show_glyphs</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_show_glyphs                   (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</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>);</programlisting>
<para>
A drawing operator that generates the shape from an array of glyphs,
rendered according to the current font face, font size
(font matrix), and font options.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a cairo context</simpara></listitem></varlistentry>
<varlistentry><term><parameter>glyphs</parameter>&#160;:</term>
<listitem><simpara>array of glyphs to show</simpara></listitem></varlistentry>
<varlistentry><term><parameter>num_glyphs</parameter>&#160;:</term>
<listitem><simpara>number of glyphs to show</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-show-text-glyphs" role="function" condition="since:1.8">
<title>cairo_show_text_glyphs ()</title>
<indexterm zone="cairo-show-text-glyphs" role="1.8"><primary sortas="show_text_glyphs">cairo_show_text_glyphs</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_show_text_glyphs              (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter>const <link linkend="char"><type>char</type></link> *utf8</parameter>,
                                                         <parameter><link linkend="int"><type>int</type></link> utf8_len</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>const <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>
This operation has rendering effects similar to <link linkend="cairo-show-glyphs"><function>cairo_show_glyphs()</function></link>
but, if the target surface supports it, uses the provided text and
cluster mapping to embed the text for the glyphs shown in the output.
If the target does not support the extended attributes, this function
acts like the basic <link linkend="cairo-show-glyphs"><function>cairo_show_glyphs()</function></link> as if it had been passed
<parameter>glyphs</parameter> and <parameter>num_glyphs</parameter>.
</para>
<para>
The mapping between <parameter>utf8</parameter> and <parameter>glyphs</parameter> is provided by an array of
<firstterm>clusters</firstterm>.  Each cluster covers a number of
text bytes and glyphs, and neighboring clusters cover neighboring
areas of <parameter>utf8</parameter> and <parameter>glyphs</parameter>.  The clusters should collectively cover <parameter>utf8</parameter>
and <parameter>glyphs</parameter> in entirety.
</para>
<para>
The first cluster always covers bytes from the beginning of <parameter>utf8</parameter>.
If <parameter>cluster_flags</parameter> do not have the <link linkend="CAIRO-TEXT-CLUSTER-FLAG-BACKWARD:CAPS"><literal>CAIRO_TEXT_CLUSTER_FLAG_BACKWARD</literal></link>
set, the first cluster also covers the beginning
of <parameter>glyphs</parameter>, otherwise it covers the end of the <parameter>glyphs</parameter> array and
following clusters move backward.
</para>
<para>
See <link linkend="cairo-text-cluster-t"><type>cairo_text_cluster_t</type></link> for constraints on valid clusters.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a cairo context</simpara></listitem></varlistentry>
<varlistentry><term><parameter>utf8</parameter>&#160;:</term>
<listitem><simpara>a string of text encoded in UTF-8</simpara></listitem></varlistentry>
<varlistentry><term><parameter>utf8_len</parameter>&#160;:</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>&#160;:</term>
<listitem><simpara>array of glyphs to show</simpara></listitem></varlistentry>
<varlistentry><term><parameter>num_glyphs</parameter>&#160;:</term>
<listitem><simpara>number of glyphs to show</simpara></listitem></varlistentry>
<varlistentry><term><parameter>clusters</parameter>&#160;:</term>
<listitem><simpara>array of cluster mapping information</simpara></listitem></varlistentry>
<varlistentry><term><parameter>num_clusters</parameter>&#160;:</term>
<listitem><simpara>number of clusters in the mapping</simpara></listitem></varlistentry>
<varlistentry><term><parameter>cluster_flags</parameter>&#160;:</term>
<listitem><simpara>cluster mapping flags</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-font-extents" role="function" condition="since:1.0">
<title>cairo_font_extents ()</title>
<indexterm zone="cairo-font-extents" role="1.0"><primary sortas="font_extents">cairo_font_extents</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_font_extents                  (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</parameter>,
                                                         <parameter><link linkend="cairo-font-extents-t"><type>cairo_font_extents_t</type></link> *extents</parameter>);</programlisting>
<para>
Gets the font extents for the currently selected font.
</para><variablelist role="params">
<varlistentry><term><parameter>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>extents</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-font-extents-t"><type>cairo_font_extents_t</type></link> object into which the results
will be stored.</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-text-extents" role="function" condition="since:1.0">
<title>cairo_text_extents ()</title>
<indexterm zone="cairo-text-extents" role="1.0"><primary sortas="text_extents">cairo_text_extents</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_text_extents                  (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</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,
(as it would be drawn by <link linkend="cairo-show-text"><function>cairo_show_text()</function></link>). 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>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>utf8</parameter>&#160;:</term>
<listitem><simpara>a NUL-terminated string of text encoded in UTF-8, or <link linkend="NULL:CAPS"><literal>NULL</literal></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>extents</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> object into which the results
will be stored</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-glyph-extents" role="function" condition="since:1.0">
<title>cairo_glyph_extents ()</title>
<indexterm zone="cairo-glyph-extents" role="1.0"><primary sortas="glyph_extents">cairo_glyph_extents</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_glyph_extents                 (<parameter><link linkend="cairo-t"><type>cairo_t</type></link> *cr</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>).
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>cr</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-t"><type>cairo_t</type></link></simpara></listitem></varlistentry>
<varlistentry><term><parameter>glyphs</parameter>&#160;:</term>
<listitem><simpara>an array of <link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link> objects</simpara></listitem></varlistentry>
<varlistentry><term><parameter>num_glyphs</parameter>&#160;:</term>
<listitem><simpara>the number of elements in <parameter>glyphs</parameter></simpara></listitem></varlistentry>
<varlistentry><term><parameter>extents</parameter>&#160;:</term>
<listitem><simpara>a <link linkend="cairo-text-extents-t"><type>cairo_text_extents_t</type></link> object into which the results
will be stored</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.0</para></refsect2>
<refsect2 id="cairo-toy-font-face-create" role="function" condition="since:1.8">
<title>cairo_toy_font_face_create ()</title>
<indexterm zone="cairo-toy-font-face-create" role="1.8"><primary sortas="toy_font_face_create">cairo_toy_font_face_create</primary></indexterm>
<programlisting><link linkend="cairo-font-face-t"><returnvalue>cairo_font_face_t</returnvalue></link> * cairo_toy_font_face_create          (<parameter>const <link linkend="char"><type>char</type></link> *family</parameter>,
                                                         <parameter><link linkend="cairo-font-slant-t"><type>cairo_font_slant_t</type></link> slant</parameter>,
                                                         <parameter><link linkend="cairo-font-weight-t"><type>cairo_font_weight_t</type></link> weight</parameter>);</programlisting>
<para>
Creates a font face from a triplet of family, slant, and weight.
These font faces are used in implementation of the the <link linkend="cairo-t"><type>cairo_t</type></link> "toy"
font API.
</para>
<para>
If <parameter>family</parameter> is the zero-length string "", the platform-specific default
family is assumed.  The default family then can be queried using
<link linkend="cairo-toy-font-face-get-family"><function>cairo_toy_font_face_get_family()</function></link>.
</para>
<para>
The <link linkend="cairo-select-font-face"><function>cairo_select_font_face()</function></link> function uses this to create font faces.
See that function for limitations and other details of toy font faces.
</para><variablelist role="params">
<varlistentry><term><parameter>family</parameter>&#160;:</term>
<listitem><simpara>a font family name, encoded in UTF-8</simpara></listitem></varlistentry>
<varlistentry><term><parameter>slant</parameter>&#160;:</term>
<listitem><simpara>the slant for the font</simpara></listitem></varlistentry>
<varlistentry><term><parameter>weight</parameter>&#160;:</term>
<listitem><simpara>the weight for the font</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara>a newly created <link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link>. Free with
<link linkend="cairo-font-face-destroy"><function>cairo_font_face_destroy()</function></link> when you are done using it.</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-toy-font-face-get-family" role="function" condition="since:1.8">
<title>cairo_toy_font_face_get_family ()</title>
<indexterm zone="cairo-toy-font-face-get-family" role="1.8"><primary sortas="toy_font_face_get_family">cairo_toy_font_face_get_family</primary></indexterm>
<programlisting>const <link linkend="char"><returnvalue>char</returnvalue></link> *        cairo_toy_font_face_get_family      (<parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>);</programlisting>
<para>
Gets the familly name of a toy font.
</para><variablelist role="params">
<varlistentry><term><parameter>font_face</parameter>&#160;:</term>
<listitem><simpara>A toy font face</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara>The family name.  This string is owned by the font face
and remains valid as long as the font face is alive (referenced).</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-toy-font-face-get-slant" role="function" condition="since:1.8">
<title>cairo_toy_font_face_get_slant ()</title>
<indexterm zone="cairo-toy-font-face-get-slant" role="1.8"><primary sortas="toy_font_face_get_slant">cairo_toy_font_face_get_slant</primary></indexterm>
<programlisting><link linkend="cairo-font-slant-t"><returnvalue>cairo_font_slant_t</returnvalue></link>  cairo_toy_font_face_get_slant       (<parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>);</programlisting>
<para>
Gets the slant a toy font.
</para><variablelist role="params">
<varlistentry><term><parameter>font_face</parameter>&#160;:</term>
<listitem><simpara>A toy font face</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara>The slant value</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-toy-font-face-get-weight" role="function" condition="since:1.8">
<title>cairo_toy_font_face_get_weight ()</title>
<indexterm zone="cairo-toy-font-face-get-weight" role="1.8"><primary sortas="toy_font_face_get_weight">cairo_toy_font_face_get_weight</primary></indexterm>
<programlisting><link linkend="cairo-font-weight-t"><returnvalue>cairo_font_weight_t</returnvalue></link> cairo_toy_font_face_get_weight      (<parameter><link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link> *font_face</parameter>);</programlisting>
<para>
Gets the weight a toy font.
</para><variablelist role="params">
<varlistentry><term><parameter>font_face</parameter>&#160;:</term>
<listitem><simpara>A toy font face</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara>The weight value</simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-glyph-allocate" role="function" condition="since:1.8">
<title>cairo_glyph_allocate ()</title>
<indexterm zone="cairo-glyph-allocate" role="1.8"><primary sortas="glyph_allocate">cairo_glyph_allocate</primary></indexterm>
<programlisting><link linkend="cairo-glyph-t"><returnvalue>cairo_glyph_t</returnvalue></link> *     cairo_glyph_allocate                (<parameter><link linkend="int"><type>int</type></link> num_glyphs</parameter>);</programlisting>
<para>
Allocates an array of <link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link>'s.
This function is only useful in implementations of
<link linkend="cairo-user-scaled-font-text-to-glyphs-func-t"><type>cairo_user_scaled_font_text_to_glyphs_func_t</type></link> where the user
needs to allocate an array of glyphs that cairo will free.
For all other uses, user can use their own allocation method
for glyphs.
</para>
<para>
This function returns <link linkend="NULL:CAPS"><literal>NULL</literal></link> if <parameter>num_glyphs</parameter> is not positive,
or if out of memory.  That means, the <link linkend="NULL:CAPS"><literal>NULL</literal></link> return value
signals out-of-memory only if <parameter>num_glyphs</parameter> was positive.
</para><variablelist role="params">
<varlistentry><term><parameter>num_glyphs</parameter>&#160;:</term>
<listitem><simpara>number of glyphs to allocate</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara>the newly allocated array of glyphs that should be
freed using <link linkend="cairo-glyph-free"><function>cairo_glyph_free()</function></link></simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-glyph-free" role="function" condition="since:1.8">
<title>cairo_glyph_free ()</title>
<indexterm zone="cairo-glyph-free" role="1.8"><primary sortas="glyph_free">cairo_glyph_free</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_glyph_free                    (<parameter><link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link> *glyphs</parameter>);</programlisting>
<para>
Frees an array of <link linkend="cairo-glyph-t"><type>cairo_glyph_t</type></link>'s allocated using <link linkend="cairo-glyph-allocate"><function>cairo_glyph_allocate()</function></link>.
This function is only useful to free glyph array returned
by <link linkend="cairo-scaled-font-text-to-glyphs"><function>cairo_scaled_font_text_to_glyphs()</function></link> where cairo returns
an array of glyphs that the user will free.
For all other uses, user can use their own allocation method
for glyphs.
</para><variablelist role="params">
<varlistentry><term><parameter>glyphs</parameter>&#160;:</term>
<listitem><simpara>array of glyphs to free, or <link linkend="NULL:CAPS"><literal>NULL</literal></link></simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-text-cluster-allocate" role="function" condition="since:1.8">
<title>cairo_text_cluster_allocate ()</title>
<indexterm zone="cairo-text-cluster-allocate" role="1.8"><primary sortas="text_cluster_allocate">cairo_text_cluster_allocate</primary></indexterm>
<programlisting><link linkend="cairo-text-cluster-t"><returnvalue>cairo_text_cluster_t</returnvalue></link> * cairo_text_cluster_allocate      (<parameter><link linkend="int"><type>int</type></link> num_clusters</parameter>);</programlisting>
<para>
Allocates an array of <link linkend="cairo-text-cluster-t"><type>cairo_text_cluster_t</type></link>'s.
This function is only useful in implementations of
<link linkend="cairo-user-scaled-font-text-to-glyphs-func-t"><type>cairo_user_scaled_font_text_to_glyphs_func_t</type></link> where the user
needs to allocate an array of text clusters that cairo will free.
For all other uses, user can use their own allocation method
for text clusters.
</para>
<para>
This function returns <link linkend="NULL:CAPS"><literal>NULL</literal></link> if <parameter>num_clusters</parameter> is not positive,
or if out of memory.  That means, the <link linkend="NULL:CAPS"><literal>NULL</literal></link> return value
signals out-of-memory only if <parameter>num_clusters</parameter> was positive.
</para><variablelist role="params">
<varlistentry><term><parameter>num_clusters</parameter>&#160;:</term>
<listitem><simpara>number of text_clusters to allocate</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis>&#160;:</term><listitem><simpara>the newly allocated array of text clusters that should be
freed using <link linkend="cairo-text-cluster-free"><function>cairo_text_cluster_free()</function></link></simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>
<refsect2 id="cairo-text-cluster-free" role="function" condition="since:1.8">
<title>cairo_text_cluster_free ()</title>
<indexterm zone="cairo-text-cluster-free" role="1.8"><primary sortas="text_cluster_free">cairo_text_cluster_free</primary></indexterm>
<programlisting><link linkend="void"><returnvalue>void</returnvalue></link>                cairo_text_cluster_free             (<parameter><link linkend="cairo-text-cluster-t"><type>cairo_text_cluster_t</type></link> *clusters</parameter>);</programlisting>
<para>
Frees an array of <link linkend="cairo-text-cluster"><type>cairo_text_cluster</type></link>'s allocated using <link linkend="cairo-text-cluster-allocate"><function>cairo_text_cluster_allocate()</function></link>.
This function is only useful to free text cluster array returned
by <link linkend="cairo-scaled-font-text-to-glyphs"><function>cairo_scaled_font_text_to_glyphs()</function></link> where cairo returns
an array of text clusters that the user will free.
For all other uses, user can use their own allocation method
for text clusters.
</para><variablelist role="params">
<varlistentry><term><parameter>clusters</parameter>&#160;:</term>
<listitem><simpara>array of text clusters to free, or <link linkend="NULL:CAPS"><literal>NULL</literal></link></simpara></listitem></varlistentry>
</variablelist><para role="since">Since 1.8</para></refsect2>

</refsect1>
<refsect1 id="cairo-text.see-also">
<title>See Also</title>
<link linkend="cairo-font-face-t"><type>cairo_font_face_t</type></link>, <link linkend="cairo-scaled-font-t"><type>cairo_scaled_font_t</type></link>, <link linkend="cairo-text-path"><function>cairo_text_path()</function></link>,
           <link linkend="cairo-glyph-path"><function>cairo_glyph_path()</function></link>
</refsect1>

</refentry>
