void GrReadArea ( GR_DRAW_ID id, GR_COORD x, GR_COORD y, GR_SIZE width, GR_SIZE height, GR_COLOR8 * colortable );
The GrReadArea function reads the color values from a specified rectangular area into a buffer. If other windows obscure the drawable area id, then the returned values inclued the values of the covering windows. Regions read outside the screen boundaries or from unmapped windows get set to black.