InvalRgn
InvalRgn
Force a region of a window to be updated This function works the same as InvalRect, except that it forces an update of a region, rather than a rectangle. It identifies a Region, in local window coordinates needing to be redrawn.
badRgn is the handle of a Region that needs to be updated.
Notes: This affects the current GrafPort, which must be defined as a window. It adds badRgn to the window's update region, forcing the region to be redrawn
and to be updated in the future.
Use InvalRect to perform the same action, but for a rectangle. Use ValidRgn to identify an area that does NOT need to be updated (e.g., a