more experimentation

cplusplus/try92.cc

@@ -0,0 +1,169 @@
+/* 
+ * compile with:
+ *
+ *      g++ -g -Wall try92.cc `pkg-config vips --cflags --libs`
+ *
+ */
+
+#include <vips/vips.h>
+
+enum VSteal {
+	NOSTEAL = 0,
+	STEAL = 1
+};
+
+class VObject
+{
+private:
+	GObject *gobject; 
+
+public:
+	VObject( GObject *new_gobject, VSteal steal = STEAL ) : 
+		gobject( new_gobject )
+	{
+		printf( "VObject constructor, obj = %p, steal = %d\n",
+				new_gobject, steal ); 
+		if( !steal ) {
+			printf( "   reffing object\n" ); 
+			g_object_ref( gobject ); 
+		}
+	}
+
+	// copy constructor
+	VObject( const VObject &vobject ) : 
+		gobject( vobject.gobject )
+	{
+		printf( "VObject copy constructor, obj = %p\n", 
+			gobject ); 
+		g_object_ref( gobject );
+		printf( "   reffing object\n" ); 
+	}
+
+	// assignment ... we must delete the old ref
+	VObject &operator=( const VObject &a )
+	{
+		GObject *old_gobject;
+
+		printf( "VObject assignment\n" );  
+		printf( "   reffing %p\n", a.gobject ); 
+		printf( "   unreffing %p\n", gobject ); 
+
+		// delete the old ref at the end ... otherwise "a = a;" could
+		// unref before reffing again 
+		old_gobject = gobject;
+		gobject = a.gobject;
+		g_object_ref( gobject ); 
+		g_object_unref( old_gobject );
+
+		return( *this ); 
+	}
+
+	~VObject()
+	{
+		printf( "VObject destructor\n" );  
+		printf( "   unreffing %p\n", gobject ); 
+		
+		g_object_unref( gobject ); 
+	}
+
+	GObject &operator*()
+	{
+		return( *gobject );
+	}
+
+	GObject *operator->()
+	{    
+		return( gobject );
+	}
+
+	GObject *get()
+	{
+		return( gobject ); 
+	}
+
+};
+
+class VImage : VObject
+{
+public:
+	VImage( VipsImage *image, VSteal steal = STEAL ) : 
+		VObject( (GObject *) image, steal )
+	{
+	}
+
+	VipsImage *get()
+	{
+		return( (VipsImage *) VObject::get() );
+	}
+
+};
+
+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 );
+	}
+
+	/*
+	 
+	VipsImage *in;
+	VipsImage *out;
+
+	if( !(in = vips_image_new_from_file( argv[1], NULL )) )
+		vips_error_exit( NULL ); 
+
+	if( vips_invert( in, &out, NULL ) ) 
+		vips_error_exit( NULL ); 
+
+	if( vips_image_write_to_file( out, argv[2], NULL ) )
+		vips_error_exit( NULL ); 
+
+	g_object_unref( in );
+	g_object_unref( out );
+
+	 */
+
+	printf( "sizeof( VipsImage *) = %zd\n", sizeof( VipsImage *) ); 
+	printf( "sizeof( VImage ) = %zd\n", sizeof( VImage ) ); 
+
+{ 
+	VipsImage *im;
+       
+	if( !(im = vips_image_new_from_file( argv[1], NULL )) )
+		vips_error_exit( NULL ); 
+
+	VImage in( im );
+	VipsImage *out;
+
+	if( vips_invert( in, &out, NULL ) ) 
+		vips_error_exit( NULL ); 
+
+	if( vips_image_write_to_file( out, argv[2], NULL ) )
+		vips_error_exit( NULL ); 
+
+	g_object_unref( out );
+} 
+
+	vips_shutdown();
+
+        return( 0 );
+}