<refentry id="gdk-pixbuf-util">
<refmeta>
<refentrytitle>Utilities</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>GDK-PIXBUF Library</refmiscinfo>
</refmeta>

<refnamediv>
<refname>Utilities</refname><refpurpose>Utility and miscellaneous convenience functions.</refpurpose>
</refnamediv>

<refsynopsisdiv><title>Synopsis</title>
<synopsis>

#include &lt;gdk-pixbuf/gdk-pixbuf.h&gt;


<link linkend="GdkPixbuf">GdkPixbuf</link>*  <link linkend="gdk-pixbuf-add-alpha">gdk_pixbuf_add_alpha</link>            (const <link linkend="GdkPixbuf">GdkPixbuf</link> *pixbuf,
                                             <link linkend="gboolean">gboolean</link> substitute_color,
                                             <link linkend="guchar">guchar</link> r,
                                             <link linkend="guchar">guchar</link> g,
                                             <link linkend="guchar">guchar</link> b);
void        <link linkend="gdk-pixbuf-copy-area">gdk_pixbuf_copy_area</link>            (const <link linkend="GdkPixbuf">GdkPixbuf</link> *src_pixbuf,
                                             int src_x,
                                             int src_y,
                                             int width,
                                             int height,
                                             <link linkend="GdkPixbuf">GdkPixbuf</link> *dest_pixbuf,
                                             int dest_x,
                                             int dest_y);
</synopsis>
</refsynopsisdiv>





<refsect1>
<title>Description</title>
  <para>
    These functions provide miscellaneous utilities for manipulating
    pixbufs.  The pixel data in pixbufs may of course be manipulated
    directly by applications, but several common operations can be
    performed by these functions instead.
  </para>
</refsect1>

<refsect1>
<title>Details</title>
<refsect2>
<title><anchor id="gdk-pixbuf-add-alpha">gdk_pixbuf_add_alpha ()</title>
<programlisting><link linkend="GdkPixbuf">GdkPixbuf</link>*  gdk_pixbuf_add_alpha            (const <link linkend="GdkPixbuf">GdkPixbuf</link> *pixbuf,
                                             <link linkend="gboolean">gboolean</link> substitute_color,
                                             <link linkend="guchar">guchar</link> r,
                                             <link linkend="guchar">guchar</link> g,
                                             <link linkend="guchar">guchar</link> b);</programlisting>
<para>
Takes an existing pixbuf and adds an alpha channel to it.  If the original
pixbuf already had alpha information, then the contents of the new pixbuf are
exactly the same as the original's.  Otherwise, the new pixbuf will have all
pixels with full opacity if <parameter>substitute_color</parameter> is <link linkend="FALSE-CAPS">FALSE</link>.  If
<parameter>substitute_color</parameter> is <link linkend="TRUE-CAPS">TRUE</link>, then the color specified by (<parameter>r</parameter>, <parameter>g</parameter>, <parameter>b</parameter>) will be
substituted for zero opacity.</para>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>pixbuf</parameter>&nbsp;:</entry>
<entry> A pixbuf.
</entry></row>
<row><entry align="right"><parameter>substitute_color</parameter>&nbsp;:</entry>
<entry> Whether to substitute a color for zero opacity.  If this
is <link linkend="FALSE-CAPS">FALSE</link>, then the (<parameter>r</parameter>, <parameter>g</parameter>, <parameter>b</parameter>) arguments will be ignored.
</entry></row>
<row><entry align="right"><parameter>r</parameter>&nbsp;:</entry>
<entry> Red value to substitute.
</entry></row>
<row><entry align="right"><parameter>g</parameter>&nbsp;:</entry>
<entry> Green value to substitute.
</entry></row>
<row><entry align="right"><parameter>b</parameter>&nbsp;:</entry>
<entry> Blue value to substitute.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry> A newly-created pixbuf with a reference count of 1.
</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="gdk-pixbuf-copy-area">gdk_pixbuf_copy_area ()</title>
<programlisting>void        gdk_pixbuf_copy_area            (const <link linkend="GdkPixbuf">GdkPixbuf</link> *src_pixbuf,
                                             int src_x,
                                             int src_y,
                                             int width,
                                             int height,
                                             <link linkend="GdkPixbuf">GdkPixbuf</link> *dest_pixbuf,
                                             int dest_x,
                                             int dest_y);</programlisting>
<para>
Copies a rectangular area from <parameter>src_pixbuf</parameter> to <parameter>dest_pixbuf</parameter>.  Conversion of
pixbuf formats is done automatically.</para>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>src_pixbuf</parameter>&nbsp;:</entry>
<entry> Source pixbuf.
</entry></row>
<row><entry align="right"><parameter>src_x</parameter>&nbsp;:</entry>
<entry> Source X coordinate within <parameter>src_pixbuf</parameter>.
</entry></row>
<row><entry align="right"><parameter>src_y</parameter>&nbsp;:</entry>
<entry> Source Y coordinate within <parameter>src_pixbuf</parameter>.
</entry></row>
<row><entry align="right"><parameter>width</parameter>&nbsp;:</entry>
<entry> Width of the area to copy.
</entry></row>
<row><entry align="right"><parameter>height</parameter>&nbsp;:</entry>
<entry> Height of the area to copy.
</entry></row>
<row><entry align="right"><parameter>dest_pixbuf</parameter>&nbsp;:</entry>
<entry> Destination pixbuf.
</entry></row>
<row><entry align="right"><parameter>dest_x</parameter>&nbsp;:</entry>
<entry> X coordinate within <parameter>dest_pixbuf</parameter>.
</entry></row>
<row><entry align="right"><parameter>dest_y</parameter>&nbsp;:</entry>
<entry> Y coordinate within <parameter>dest_pixbuf</parameter>.
</entry></row>
</tbody></tgroup></informaltable></refsect2>

</refsect1>



<refsect1>
<title>See Also</title>
  <para>
    <link linkend="GdkPixbuf">GdkPixbuf</link>
  </para>
</refsect1>

</refentry>
