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<!-- ##### SECTION Title ##### -->
cairo_matrix_t
<!-- ##### SECTION Short_Description ##### -->
Transformation matrices
<!-- ##### SECTION Long_Description ##### -->
<para><indexterm><primary>types</primary><secondary>cairo_matrix</secondary></indexterm><indexterm><primary/></indexterm>
<structname>cairo_matrix_t</structname> is used throughout
Cairo to represents between different coordinates spaces.
A <structname>cairo_matrix</structname> holds an affine
transformation, such as a scale, rotation, or shear, or a
combination of those. Mathematically, the effect of an affine
transformation on a point (<literal>x</literal>,<literal>y</literal>) is given by:
</para>
<programlisting>
x_new = x * a + y * c + tx;
y_new = x * b + y * d + ty;
</programlisting>
<para>
The parameters <literal>a</literal>, <literal>b</literal>,
<literal>c</literal>, <literal>d</literal>, <literal>tx</literal>,
<literal>ty</literal> can be retrieved with
cairo_matrix_get_affine() and set with cairo_matrix_get_affine().
</para>
<para>
The primary use of transformation matrices in Cairo is as the
current transformation matrix in a #cairo_t. The current
transformation matrix gives the transformation from user space
coordinates to device coordinates. See cairo_set_matrix(),
cairo_current_matrix().
</para>
<!-- ##### SECTION See_Also ##### -->
<para>
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### STRUCT cairo_matrix_t ##### -->
<para>
</para>
@xx:
@yx:
@xy:
@yy:
@x0:
@y0:
<!-- ##### FUNCTION cairo_matrix_init ##### -->
<para>
</para>
@matrix:
@xx:
@yx:
@xy:
@yy:
@x0:
@y0:
<!-- ##### FUNCTION cairo_matrix_init_identity ##### -->
<para>
</para>
@matrix:
<!-- ##### FUNCTION cairo_matrix_init_translate ##### -->
<para>
</para>
@matrix:
@tx:
@ty:
<!-- ##### FUNCTION cairo_matrix_init_scale ##### -->
<para>
</para>
@matrix:
@sx:
@sy:
<!-- ##### FUNCTION cairo_matrix_init_rotate ##### -->
<para>
</para>
@matrix:
@radians:
<!-- ##### FUNCTION cairo_matrix_translate ##### -->
<para>
</para>
@matrix:
@tx:
@ty:
<!-- ##### FUNCTION cairo_matrix_scale ##### -->
<para>
</para>
@matrix:
@sx:
@sy:
<!-- ##### FUNCTION cairo_matrix_rotate ##### -->
<para>
</para>
@matrix:
@radians:
<!-- ##### FUNCTION cairo_matrix_invert ##### -->
<para>
</para>
@matrix:
@Returns:
<!-- ##### FUNCTION cairo_matrix_multiply ##### -->
<para>
</para>
@result:
@a:
@b:
<!-- ##### FUNCTION cairo_matrix_transform_distance ##### -->
<para>
</para>
@matrix:
@dx:
@dy:
<!-- ##### FUNCTION cairo_matrix_transform_point ##### -->
<para>
</para>
@matrix:
@x:
@y:
|
