PtSurfaceCalcBoundingBox(), PtSurfaceCalcBoundingBoxById()

Calculate the bounding box for a control surface

Synopsis:

PhRect_t *PtSurfaceCalcBoundingBox(
              PtSurface_t *surface );

PhRect_t *PtSurfaceCalcBoundingBoxById(
              PtWidget_t *widget,
              unsigned char surface_id );

Library:

ph

Description:

These functions calculate the bounding box for a control surface. They differ in the way they identify the control surface:

PtSurfaceCalcBoundingBox(): Uses the surface argument, which points to a PtSurface_t structure that describes the control surface. This pointer must not be NULL.
PtSurfaceCalcBoundingBoxById(): Searches the control surfaces belonging to the given widget for the one with an ID of surface_id.

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.

Returns:

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.

Classification:

Photon

Safety:
Interrupt handler	No
Signal handler	No
Thread	No

See also:

PhRect_t, PtCalcSurface(), PtCalcSurfaceByAction(), PtCalcSurfaceById(), PtSurfaceExtent(), PtSurfaceExtentById(), PtSurfaceRect(), PtSurfaceRectById()

Control Surfaces chapter of the Photon Programmer's Guide