Creates region that describes covers the area where the given @surface is more than 50% opaque.
This function takes into account device offsets that might be set with cairo_surface_set_device_offset().
a cairo surface
A #cairo_region_t; must be freed with cairo_region_destroy()
See Implementation
Creates region that describes covers the area where the given @surface is more than 50% opaque.
This function takes into account device offsets that might be set with cairo_surface_set_device_offset().