cairo-types.xml

按照官方的说法：Cairo is a vector graphics library with cross-device output support. 翻译过来

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

<refnamediv>
<refname>Types</refname>
<refpurpose>Generic data types used in the cairo API</refpurpose>
<!--[<xref linkend="desc" endterm="desc.title"/>]-->
</refnamediv>

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

<synopsis>



typedef     <link linkend="cairo-bool-t">cairo_bool_t</link>;
            <link linkend="cairo-user-data-key-t">cairo_user_data_key_t</link>;
<link linkend="void">void</link>        (<link linkend="cairo-destroy-func-t">*cairo_destroy_func_t</link>)         (<link linkend="void">void</link> *data);
</synopsis>
</refsynopsisdiv>









<refsect1 id="desc">
<title id="desc.title">Description</title>
<para>

</para>
</refsect1>

<refsect1 id="details">
<title id="details.title">Details</title>
<refsect2>
<title><anchor id="cairo-bool-t" role="typedef"/>cairo_bool_t</title>
<indexterm><primary>cairo_bool_t</primary></indexterm><programlisting>typedef int cairo_bool_t;
</programlisting>
<para>
<link linkend="cairo-bool-t"><type>cairo_bool_t</type></link> is used for boolean values. Returns of type
<link linkend="cairo-bool-t"><type>cairo_bool_t</type></link> will always be either 0 or 1, but testing against
these values explicitly is not encouraged; just use the
value as a boolean condition.
</para>
<para>
<informalexample><programlisting>
 if (cairo_in_stroke (cr, x, y)) {
     /<!-- -->* do something *<!-- -->/
 }
</programlisting></informalexample></para>
<para>

</para></refsect2>
<refsect2>
<title><anchor id="cairo-user-data-key-t" role="struct"/>cairo_user_data_key_t</title>
<indexterm><primary>cairo_user_data_key_t</primary></indexterm><programlisting>typedef struct {
    int unused;
} cairo_user_data_key_t;
</programlisting>
<para>
<link linkend="cairo-user-data-key-t"><type>cairo_user_data_key_t</type></link> is used for attaching user data to cairo
data structures.  The actual contents of the struct is never used,
and there is no need to initialize the object; only the unique
address of a <link linkend="cairo-data-key-t"><type>cairo_data_key_t</type></link> object is used.  Typically, you
would just use the address of a static <link linkend="cairo-data-key-t"><type>cairo_data_key_t</type></link> object.</para>
<para>

</para><variablelist role="struct">
<varlistentry>
<term><link linkend="int">int</link>&nbsp;<structfield>unused</structfield>;</term>
<listitem><simpara> not used; ignore.
</simpara></listitem>
</varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="cairo-destroy-func-t" role="function"/>cairo_destroy_func_t ()</title>
<indexterm><primary>cairo_destroy_func_t</primary></indexterm><programlisting><link linkend="void">void</link>        (*cairo_destroy_func_t)         (<link linkend="void">void</link> *data);</programlisting>
<para>
<link linkend="cairo-destroy-func-t"><type>cairo_destroy_func_t</type></link> the type of function which is called when a
data element is destroyed. It is passed the pointer to the data
element and should free any memory and resources allocated for it.</para>
<para>

</para><variablelist role="params">
<varlistentry><term><parameter>data</parameter>&nbsp;:</term>
<listitem><simpara> The data element being destroyed.
</simpara></listitem></varlistentry>
</variablelist></refsect2>

</refsect1>




</refentry>