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diff --git a/doc/public/xml/cairo-png.xml b/doc/public/xml/cairo-png.xml new file mode 100644 index 000000000..0ccace961 --- /dev/null +++ b/doc/public/xml/cairo-png.xml @@ -0,0 +1,316 @@ +<?xml version='1.0' encoding='UTF-8'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ +<!ENTITY version SYSTEM "version.xml"> +]> +<refentry id="cairo-PNG-Support"> +<refmeta> +<refentrytitle role="top_of_page" id="cairo-PNG-Support.top_of_page">PNG Support</refentrytitle> +<manvolnum>3</manvolnum> +<refmiscinfo> + CAIRO Library +</refmiscinfo> +</refmeta> +<refnamediv> +<refname>PNG Support</refname> +<refpurpose>Reading and writing PNG images</refpurpose> +</refnamediv> + +<refsect1 id="cairo-PNG-Support.functions" role="functions_proto"> +<title role="functions_proto.title">Functions</title> +<informaltable pgwide="1" frame="none"> +<tgroup cols="2"> +<colspec colname="functions_return" colwidth="150px"/> +<colspec colname="functions_name"/> +<tbody> +<row><entry role="function_type"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> * +</entry><entry role="function_name"><link linkend="cairo-image-surface-create-from-png">cairo_image_surface_create_from_png</link> <phrase role="c_punctuation">()</phrase></entry></row> +<row><entry role="function_type"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> +</entry><entry role="function_name"><phrase role="c_punctuation">(</phrase><link linkend="cairo-read-func-t">*cairo_read_func_t</link><phrase role="c_punctuation">)</phrase> <phrase role="c_punctuation">()</phrase></entry></row> +<row><entry role="function_type"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> * +</entry><entry role="function_name"><link linkend="cairo-image-surface-create-from-png-stream">cairo_image_surface_create_from_png_stream</link> <phrase role="c_punctuation">()</phrase></entry></row> +<row><entry role="function_type"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> +</entry><entry role="function_name"><link linkend="cairo-surface-write-to-png">cairo_surface_write_to_png</link> <phrase role="c_punctuation">()</phrase></entry></row> +<row><entry role="function_type"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> +</entry><entry role="function_name"><phrase role="c_punctuation">(</phrase><link linkend="cairo-write-func-t">*cairo_write_func_t</link><phrase role="c_punctuation">)</phrase> <phrase role="c_punctuation">()</phrase></entry></row> +<row><entry role="function_type"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> +</entry><entry role="function_name"><link linkend="cairo-surface-write-to-png-stream">cairo_surface_write_to_png_stream</link> <phrase role="c_punctuation">()</phrase></entry></row> + +</tbody> +</tgroup> +</informaltable> +</refsect1> +<refsect1 id="cairo-PNG-Support.other" role="other_proto"> +<title role="other_proto.title">Types and Values</title> +<informaltable role="enum_members_table" pgwide="1" frame="none"> +<tgroup cols="2"> +<colspec colname="name" colwidth="150px"/> +<colspec colname="description"/> +<tbody> +<row><entry role="define_keyword">#define</entry><entry role="function_name"><link linkend="CAIRO-HAS-PNG-FUNCTIONS:CAPS">CAIRO_HAS_PNG_FUNCTIONS</link></entry></row> + +</tbody> +</tgroup> +</informaltable> +</refsect1> +<refsect1 id="cairo-PNG-Support.object-hierarchy" role="object_hierarchy"> +<title role="object_hierarchy.title">Object Hierarchy</title> +<screen> +</screen> +</refsect1> + + +<refsect1 id="cairo-PNG-Support.description" role="desc"> +<title role="desc.title">Description</title> +<para>The PNG functions allow reading PNG images into image surfaces, and writing +any surface to a PNG file.</para> +<para>It is a toy API. It only offers very simple support for reading and +writing PNG files, which is sufficient for testing and +demonstration purposes. Applications which need more control over +the generated PNG file should access the pixel data directly, using +<link linkend="cairo-image-surface-get-data"><function>cairo_image_surface_get_data()</function></link> or a backend-specific access +function, and process it with another library, e.g. gdk-pixbuf or +libpng.</para> + +</refsect1> +<refsect1 id="cairo-PNG-Support.functions_details" role="details"> +<title role="details.title">Functions</title> +<refsect2 id="cairo-image-surface-create-from-png" role="function" condition="since:1.0"> +<title>cairo_image_surface_create_from_png ()</title> +<indexterm zone="cairo-image-surface-create-from-png" role="1.0"><primary sortas="image_surface_create_from_png">cairo_image_surface_create_from_png</primary></indexterm> +<programlisting language="C"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> * +cairo_image_surface_create_from_png (<parameter>const <link linkend="char"><type>char</type></link> *filename</parameter>);</programlisting> +<para>Creates a new image surface and initializes the contents to the +given PNG file.</para> +<refsect3 role="parameters"> +<title>Parameters</title> +<informaltable role="parameters_table" pgwide="1" frame="none"> +<tgroup cols="3"> +<colspec colname="parameters_name" colwidth="150px"/> +<colspec colname="parameters_description"/> +<colspec colname="parameters_annotations" colwidth="200px"/> +<tbody> +<row><entry role="parameter_name"><para>filename</para></entry> +<entry role="parameter_description"><para>name of PNG file to load</para></entry> +<entry role="parameter_annotations"></entry></row> +</tbody></tgroup></informaltable> +</refsect3><refsect3 role="returns"> +<title>Returns</title> +<para> a new <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> initialized with the contents +of the PNG file, or a "nil" surface if any error occurred. A nil +surface can be checked for with cairo_surface_status(surface) which +may return one of the following values:</para> +<para><link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link> +<link linkend="CAIRO-STATUS-FILE-NOT-FOUND:CAPS"><literal>CAIRO_STATUS_FILE_NOT_FOUND</literal></link> +<link linkend="CAIRO-STATUS-READ-ERROR:CAPS"><literal>CAIRO_STATUS_READ_ERROR</literal></link></para> +<para>Alternatively, you can allow errors to propagate through the drawing +operations and check the status on the context upon completion +using <link linkend="cairo-status"><function>cairo_status()</function></link>.</para> +<para></para> +</refsect3><para role="since">Since 1.0</para></refsect2> +<refsect2 id="cairo-read-func-t" role="function" condition="since:1.0"> +<title>cairo_read_func_t ()</title> +<indexterm zone="cairo-read-func-t" role="1.0"><primary sortas="read_func_t">cairo_read_func_t</primary></indexterm> +<programlisting language="C"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> +<phrase role="c_punctuation">(</phrase>*cairo_read_func_t<phrase role="c_punctuation">)</phrase> (<parameter><link linkend="void"><type>void</type></link> *closure</parameter>, + <parameter>unsigned <link linkend="char"><type>char</type></link> *data</parameter>, + <parameter>unsigned <link linkend="int"><type>int</type></link> length</parameter>);</programlisting> +<para><link linkend="cairo-read-func-t"><type>cairo_read_func_t</type></link> is the type of function which is called when a +backend needs to read data from an input stream. It is passed the +closure which was specified by the user at the time the read +function was registered, the buffer to read the data into and the +length of the data in bytes. The read function should return +<link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link> if all the data was successfully read, +<link linkend="CAIRO-STATUS-READ-ERROR:CAPS"><literal>CAIRO_STATUS_READ_ERROR</literal></link> otherwise.</para> +<refsect3 role="parameters"> +<title>Parameters</title> +<informaltable role="parameters_table" pgwide="1" frame="none"> +<tgroup cols="3"> +<colspec colname="parameters_name" colwidth="150px"/> +<colspec colname="parameters_description"/> +<colspec colname="parameters_annotations" colwidth="200px"/> +<tbody> +<row><entry role="parameter_name"><para>closure</para></entry> +<entry role="parameter_description"><para>the input closure</para></entry> +<entry role="parameter_annotations"></entry></row> +<row><entry role="parameter_name"><para>data</para></entry> +<entry role="parameter_description"><para>the buffer into which to read the data</para></entry> +<entry role="parameter_annotations"></entry></row> +<row><entry role="parameter_name"><para>length</para></entry> +<entry role="parameter_description"><para>the amount of data to read</para></entry> +<entry role="parameter_annotations"></entry></row> +</tbody></tgroup></informaltable> +</refsect3><refsect3 role="returns"> +<title>Returns</title> +<para> the status code of the read operation</para> +<para></para> +</refsect3><para role="since">Since 1.0</para></refsect2> +<refsect2 id="cairo-image-surface-create-from-png-stream" role="function" condition="since:1.0"> +<title>cairo_image_surface_create_from_png_stream ()</title> +<indexterm zone="cairo-image-surface-create-from-png-stream" role="1.0"><primary sortas="image_surface_create_from_png_stream">cairo_image_surface_create_from_png_stream</primary></indexterm> +<programlisting language="C"><link linkend="cairo-surface-t"><returnvalue>cairo_surface_t</returnvalue></link> * +cairo_image_surface_create_from_png_stream + (<parameter><link linkend="cairo-read-func-t"><type>cairo_read_func_t</type></link> read_func</parameter>, + <parameter><link linkend="void"><type>void</type></link> *closure</parameter>);</programlisting> +<para>Creates a new image surface from PNG data read incrementally +via the <parameter>read_func</parameter> + function.</para> +<refsect3 role="parameters"> +<title>Parameters</title> +<informaltable role="parameters_table" pgwide="1" frame="none"> +<tgroup cols="3"> +<colspec colname="parameters_name" colwidth="150px"/> +<colspec colname="parameters_description"/> +<colspec colname="parameters_annotations" colwidth="200px"/> +<tbody> +<row><entry role="parameter_name"><para>read_func</para></entry> +<entry role="parameter_description"><para>function called to read the data of the file</para></entry> +<entry role="parameter_annotations"></entry></row> +<row><entry role="parameter_name"><para>closure</para></entry> +<entry role="parameter_description"><para>data to pass to <parameter>read_func</parameter> +.</para></entry> +<entry role="parameter_annotations"></entry></row> +</tbody></tgroup></informaltable> +</refsect3><refsect3 role="returns"> +<title>Returns</title> +<para> a new <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> initialized with the contents +of the PNG file or a "nil" surface if the data read is not a valid PNG image +or memory could not be allocated for the operation. A nil +surface can be checked for with cairo_surface_status(surface) which +may return one of the following values:</para> +<para><link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link> +<link linkend="CAIRO-STATUS-READ-ERROR:CAPS"><literal>CAIRO_STATUS_READ_ERROR</literal></link></para> +<para>Alternatively, you can allow errors to propagate through the drawing +operations and check the status on the context upon completion +using <link linkend="cairo-status"><function>cairo_status()</function></link>.</para> +<para></para> +</refsect3><para role="since">Since 1.0</para></refsect2> +<refsect2 id="cairo-surface-write-to-png" role="function" condition="since:1.0"> +<title>cairo_surface_write_to_png ()</title> +<indexterm zone="cairo-surface-write-to-png" role="1.0"><primary sortas="surface_write_to_png">cairo_surface_write_to_png</primary></indexterm> +<programlisting language="C"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> +cairo_surface_write_to_png (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>, + <parameter>const <link linkend="char"><type>char</type></link> *filename</parameter>);</programlisting> +<para>Writes the contents of <parameter>surface</parameter> + to a new file <parameter>filename</parameter> + as a PNG +image.</para> +<refsect3 role="parameters"> +<title>Parameters</title> +<informaltable role="parameters_table" pgwide="1" frame="none"> +<tgroup cols="3"> +<colspec colname="parameters_name" colwidth="150px"/> +<colspec colname="parameters_description"/> +<colspec colname="parameters_annotations" colwidth="200px"/> +<tbody> +<row><entry role="parameter_name"><para>surface</para></entry> +<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> with pixel contents</para></entry> +<entry role="parameter_annotations"></entry></row> +<row><entry role="parameter_name"><para>filename</para></entry> +<entry role="parameter_description"><para>the name of a file to write to</para></entry> +<entry role="parameter_annotations"></entry></row> +</tbody></tgroup></informaltable> +</refsect3><refsect3 role="returns"> +<title>Returns</title> +<para> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link> if the PNG file was written +successfully. Otherwise, <link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link> if memory could not +be allocated for the operation or +<link linkend="CAIRO-STATUS-SURFACE-TYPE-MISMATCH:CAPS"><literal>CAIRO_STATUS_SURFACE_TYPE_MISMATCH</literal></link> if the surface does not have +pixel contents, or <link linkend="CAIRO-STATUS-WRITE-ERROR:CAPS"><literal>CAIRO_STATUS_WRITE_ERROR</literal></link> if an I/O error occurs +while attempting to write the file.</para> +<para></para> +</refsect3><para role="since">Since 1.0</para></refsect2> +<refsect2 id="cairo-write-func-t" role="function" condition="since:1.0"> +<title>cairo_write_func_t ()</title> +<indexterm zone="cairo-write-func-t" role="1.0"><primary sortas="write_func_t">cairo_write_func_t</primary></indexterm> +<programlisting language="C"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> +<phrase role="c_punctuation">(</phrase>*cairo_write_func_t<phrase role="c_punctuation">)</phrase> (<parameter><link linkend="void"><type>void</type></link> *closure</parameter>, + <parameter>const unsigned <link linkend="char"><type>char</type></link> *data</parameter>, + <parameter>unsigned <link linkend="int"><type>int</type></link> length</parameter>);</programlisting> +<para><link linkend="cairo-write-func-t"><type>cairo_write_func_t</type></link> is the type of function which is called when a +backend needs to write data to an output stream. It is passed the +closure which was specified by the user at the time the write +function was registered, the data to write and the length of the +data in bytes. The write function should return +<link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link> if all the data was successfully written, +<link linkend="CAIRO-STATUS-WRITE-ERROR:CAPS"><literal>CAIRO_STATUS_WRITE_ERROR</literal></link> otherwise.</para> +<refsect3 role="parameters"> +<title>Parameters</title> +<informaltable role="parameters_table" pgwide="1" frame="none"> +<tgroup cols="3"> +<colspec colname="parameters_name" colwidth="150px"/> +<colspec colname="parameters_description"/> +<colspec colname="parameters_annotations" colwidth="200px"/> +<tbody> +<row><entry role="parameter_name"><para>closure</para></entry> +<entry role="parameter_description"><para>the output closure</para></entry> +<entry role="parameter_annotations"></entry></row> +<row><entry role="parameter_name"><para>data</para></entry> +<entry role="parameter_description"><para>the buffer containing the data to write</para></entry> +<entry role="parameter_annotations"></entry></row> +<row><entry role="parameter_name"><para>length</para></entry> +<entry role="parameter_description"><para>the amount of data to write</para></entry> +<entry role="parameter_annotations"></entry></row> +</tbody></tgroup></informaltable> +</refsect3><refsect3 role="returns"> +<title>Returns</title> +<para> the status code of the write operation</para> +<para></para> +</refsect3><para role="since">Since 1.0</para></refsect2> +<refsect2 id="cairo-surface-write-to-png-stream" role="function" condition="since:1.0"> +<title>cairo_surface_write_to_png_stream ()</title> +<indexterm zone="cairo-surface-write-to-png-stream" role="1.0"><primary sortas="surface_write_to_png_stream">cairo_surface_write_to_png_stream</primary></indexterm> +<programlisting language="C"><link linkend="cairo-status-t"><returnvalue>cairo_status_t</returnvalue></link> +cairo_surface_write_to_png_stream (<parameter><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> *surface</parameter>, + <parameter><link linkend="cairo-write-func-t"><type>cairo_write_func_t</type></link> write_func</parameter>, + <parameter><link linkend="void"><type>void</type></link> *closure</parameter>);</programlisting> +<para>Writes the image surface to the write function.</para> +<refsect3 role="parameters"> +<title>Parameters</title> +<informaltable role="parameters_table" pgwide="1" frame="none"> +<tgroup cols="3"> +<colspec colname="parameters_name" colwidth="150px"/> +<colspec colname="parameters_description"/> +<colspec colname="parameters_annotations" colwidth="200px"/> +<tbody> +<row><entry role="parameter_name"><para>surface</para></entry> +<entry role="parameter_description"><para>a <link linkend="cairo-surface-t"><type>cairo_surface_t</type></link> with pixel contents</para></entry> +<entry role="parameter_annotations"></entry></row> +<row><entry role="parameter_name"><para>write_func</para></entry> +<entry role="parameter_description"><para>a <link linkend="cairo-write-func-t"><type>cairo_write_func_t</type></link></para></entry> +<entry role="parameter_annotations"></entry></row> +<row><entry role="parameter_name"><para>closure</para></entry> +<entry role="parameter_description"><para>closure data for the write function</para></entry> +<entry role="parameter_annotations"></entry></row> +</tbody></tgroup></informaltable> +</refsect3><refsect3 role="returns"> +<title>Returns</title> +<para> <link linkend="CAIRO-STATUS-SUCCESS:CAPS"><literal>CAIRO_STATUS_SUCCESS</literal></link> if the PNG file was written +successfully. Otherwise, <link linkend="CAIRO-STATUS-NO-MEMORY:CAPS"><literal>CAIRO_STATUS_NO_MEMORY</literal></link> is returned if +memory could not be allocated for the operation, +<link linkend="CAIRO-STATUS-SURFACE-TYPE-MISMATCH:CAPS"><literal>CAIRO_STATUS_SURFACE_TYPE_MISMATCH</literal></link> if the surface does not have +pixel contents.</para> +<para></para> +</refsect3><para role="since">Since 1.0</para></refsect2> + +</refsect1> +<refsect1 id="cairo-PNG-Support.other_details" role="details"> +<title role="details.title">Types and Values</title> +<refsect2 id="CAIRO-HAS-PNG-FUNCTIONS:CAPS" role="macro" condition="since:1.0"> +<title>CAIRO_HAS_PNG_FUNCTIONS</title> +<indexterm zone="CAIRO-HAS-PNG-FUNCTIONS:CAPS" role="1.0"><primary sortas="HAS_PNG_FUNCTIONS">CAIRO_HAS_PNG_FUNCTIONS</primary></indexterm> +<programlisting language="C">#define CAIRO_HAS_PNG_FUNCTIONS 1 +</programlisting> +<para>Defined if the PNG functions are available. +This macro can be used to conditionally compile code using the cairo +PNG functions.</para> +<para role="since">Since 1.0</para></refsect2> + +</refsect1> +<refsect1 id="cairo-PNG-Support.see-also"> +<title>See Also</title> +<para><link linkend="cairo-surface-t"><type>cairo_surface_t</type></link></para> + +</refsect1> + +</refentry> |