libvips/doc/reference/extending.xml
2014-08-08 17:34:30 +01:00

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XML

<?xml version="1.0"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
<refentry id="extending">
<refmeta>
<refentrytitle>Extending VIPS</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>VIPS Library</refmiscinfo>
</refmeta>
<refnamediv>
<refname>Extending</refname>
<refpurpose>How to add operations to VIPS</refpurpose>
</refnamediv>
<refsect1 id="extending-subclassing">
<title>Adding operations to VIPS</title>
<para>
All about subclassing. Copy-paste from the blog post about extending
vips8.
</para>
<para>
If you are writing a language binding, you won't need these. Instead, make
a new operation with vips_operation_new() (all it does is look up the
operation by name with vips_type_find(), then call g_object_new() for you),
then use vips_argument_map() and friends to loop over the operation's
arguments setting them. Once you have set all arguments, use
vips_cache_operation_build() to look up the operation in the cache and
either build or dup it. If something goes wrong, you'll need to use
vips_object_unref_outputs() and g_object_unref() to free the
partially-built object.
</para>
</refsect1>
</refentry>