test libvips load from stream

load-from-stream.c

/* test load from stream
 *
 * compile with:
 *
 *      gcc -g -Wall load-from-stream.c `pkg-config vips --cflags --libs`
 *
 * test with:
 *
 *      cat k2.jpg k4.jpg | ./a.out
 */

#include <vips/vips.h>

int
main( int argc, char **argv )
{
	GOptionContext *context;
	GOptionGroup *main_group;
	GError *error = NULL;

	VipsStreamInput *stream;

	if( vips_init( argv[0] ) )
		vips_error_exit( NULL ); 

	context = g_option_context_new( "load-from-stream - "
		"load jpegs from stdin" );

	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 );
	}

	stream = vips_stream_input_new_from_descriptor( 0 ); 

	while( !vips_stream_input_eof( stream ) ) {
		VipsImage *x;
		double avg;

		if( vips_jpegload_stream( stream, &x, NULL ) )
			vips_error_exit( NULL );
		if( vips_avg( x, &avg, NULL ) ) 
			vips_error_exit( NULL );
		g_object_unref( x );

		printf( "avg = %g\n", avg );
	}

	g_object_unref( stream ); 

        return( 0 );
}