pOffset

Pointer to a POINT structure that contains the offset of the underlay bitmap, with respect to the destination bitmap. The method will use this point to calculate the parts of the underlay bitmap that will be applied to the mask bitmap. Using this point lets the user provide the feel of continuous texture when applying this method to neighboring parts inside the destination bitmap using the same or a different mask. If the UnderlayBitmap parameter is set to 0 also set this parameter to Nil (NULL).