Returns an IRect that is the updated bounds of inputRect after this filter has been applied.
The local (pre-transformed) bounding box of the geometry being drawn before the filter is applied.
Optionalctm: InputMatrixIf provided, the current transform at the time the filter would be used.
OptionaloutputRect: IRectIf provided, the result will be output to this array rather than allocating a new one.
an IRect describing the updated bounds.
See ImageFilter.h for more on this class. The objects are opaque.