Set a layer's source viewport
#include <gf/gf.h> void gf_layer_set_src_viewport( gf_layer_t layer, int x1, int y1, int x2, int y2 );
This function sets a layer's source viewport. The source viewport specifies the area of the target surface which the layer displays in the destination viewport.
There may be hardware limitations on viewports. Check these flag bits in gf_layer_info_t.caps filled in by gf_layer_query():
|Changes to the layer's paramters are enqueued. You need to call gf_layer_update() to make them take effect.|
QNX Graphics Framework
“Viewports” in the Working with Layers, Surfaces and Contexts chapter