Note that both are defined as gint16 values, so the coordinates are limited to between -32,768 and 32,767. Defines the position and size of a rectangle. The fill rule is only relevant for polygons which overlap themselves. Creates a new region containing the area rectangle . Positive values shrink the region.
Negative values expand it.
That is, after calling this function source2 will be unchanged and source1 will be the areas the two regions have in common. Sets the area of source1 to the intersection of the areas of source1 and source2 . The resulting area is the set of pixels contained in both source1 and source2 . Subtracts the area of source2 from the area source1 . The resulting area is the set of pixels contained in source1 but not in source2 .