88 lines
2.1 KiB
XML
88 lines
2.1 KiB
XML
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<?xml version="1.0"?>
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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]>
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<refentry id="using-from-cpp">
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<refmeta>
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<refentrytitle>VIPS from C++</refentrytitle>
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<manvolnum>3</manvolnum>
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<refmiscinfo>VIPS Library</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>Using VIPS</refname>
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<refpurpose>How to use the VIPS library from C++</refpurpose>
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</refnamediv>
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<refsect1 id="using-cpp">
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<title>Using VIPS from C++</title>
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<para>
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VIPS comes with a convenient C++ API. It is a very thin wrapper over the
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C API and provides automatic reference counting, exceptions, operator
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overloads, and automatic constant expansion. You can drop down to the C
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API at any point, so all the C API docs also work for C++.
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</para>
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<example>
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<title>VIPS from C++ example</title>
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<programlisting language="C++">
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/* compile with:
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* g++ -g -Wall try.cc `pkg-config vips-cc --cflags --libs`
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*/
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#include <vips/vips8>
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using namespace vips;
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int
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main( int argc, char **argv )
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{
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GOptionContext *context;
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GOptionGroup *main_group;
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GError *error = NULL;
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if( vips_init( argv[0] ) )
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vips_error_exit( NULL );
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context = g_option_context_new( "" );
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main_group = g_option_group_new( NULL, NULL, NULL, NULL, NULL );
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g_option_context_set_main_group( context, main_group );
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g_option_context_add_group( context, vips_get_option_group() );
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if( !g_option_context_parse( context, &argc, &argv, &error ) ) {
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if( error ) {
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fprintf( stderr, "%s\n", error->message );
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g_error_free( error );
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}
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vips_error_exit( NULL );
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}
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VImage in = VImage::new_from_file( argv[1],
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VImage::option()->
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set( "access", VIPS_ACCESS_SEQUENTIAL_UNBUFFERED ) );
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double avg;
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avg = in.avg();
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printf( "avg = %g\n", avg );
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VImage out = in.embed( 10, 10, 1000, 1000,
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VImage::option()->
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set( "extend", VIPS_EXTEND_BACKGROUND )->
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set( "background", 128 ) );
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out.write_to_file( argv[2] );
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vips_shutdown();
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return( 0 );
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}
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</programlisting>
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</example>
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</refsect1>
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</refentry>
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