Returns the width (in pixels) of each element in the specified plane.
- iOS 3.0+
- macOS 10.6+
- Mac Catalyst 13.0+
- tvOS 9.0+
If the planeIndex is greater than or equal to the plane count of the IOSurface, zero is returned.... with one exception. If this IOSurface has zero planes and a planeIndex of zero is passed in, the routines function just like the non-planar APIs. This is to allow higher level code to treat planar and non-planar buffers is a more uniform fashion.