libvips/cplusplus/examples/buffer.cpp

62 lines
1.4 KiB
C++

/*
* compile with:
*
* g++ -g -Wall buffer.cpp `pkg-config vips-cpp --cflags --libs`
*
*/
#define DEBUG
#include <vips/vips8>
using namespace vips;
int
main( int argc, char **argv )
{
GOptionContext *context;
GOptionGroup *main_group;
GError *error = NULL;
if( VIPS_INIT( argv[0] ) )
vips_error_exit( NULL );
context = g_option_context_new( "" );
main_group = g_option_group_new( NULL, NULL, NULL, NULL, NULL );
g_option_context_set_main_group( context, main_group );
g_option_context_add_group( context, vips_get_option_group() );
if( !g_option_context_parse( context, &argc, &argv, &error ) ) {
if( error ) {
fprintf( stderr, "%s\n", error->message );
g_error_free( error );
}
vips_error_exit( NULL );
}
// load an image from a file
VImage im = VImage::new_from_file( argv[1],
VImage::option()->set( "access", "sequential-unbuffered" ) );
printf( "loaded %d x %d pixel image from %s\n",
im.width(), im.height(), argv[1] );
// write to a formatted memory buffer
size_t size;
void *buf;
im.write_to_buffer( ".png", &buf, &size );
printf( "written to memory %p in png format, %zd bytes\n", buf, size );
// load from the formatted memory area
im = VImage::new_from_buffer( buf, size, "" );
printf( "loaded from memory, %d x %d pixel image\n",
im.width(), im.height() );
// write back to a file
im.write_to_file( argv[2] );
printf( "written back to %s\n", argv[2] );
return( 0 );
}