Calculate the bounding box for a control surface
PhRect_t *PtSurfaceCalcBoundingBox( PtSurface_t *surface ); PhRect_t *PtSurfaceCalcBoundingBoxById( PtWidget_t *widget, unsigned char surface_id );
These functions calculate the bounding box for a control surface. They differ in the way they identify the control surface:
You should call one of these functions whenever you modify the points defining a surface. Although these functions are mainly targeted as a convenience function for polygonal surfaces, they also ensure that the upper-left/lower-right corners of a rectangular or elliptical surface never get inverted.
A pointer to a PhRect_t structure that defines the bounding rectangle of the surface. PtSurfaceCalcBoundingBoxById() returns NULL if it couldn't find the control surface with the given ID.
PhRect_t, PtCalcSurface(), PtCalcSurfaceByAction(), PtCalcSurfaceById(), PtSurfaceExtent(), PtSurfaceExtentById(), PtSurfaceRect(), PtSurfaceRectById()
Control Surfaces chapter of the Photon Programmer's Guide