ValidRgn

Keep a Region from being updated

#include <Windows.h> Window Manager

void ValidRgn(goodRgn );

RgnHandle goodRgn ; handle leading to Region in local coordinates

ValidRgn avoids redundant screen drawing by telling the Window Manager

when an area of the window need not be redrawn.

Notes: This can be used after sizing a document window and then drawing the

controls. Since the scroll bars and size box are now valid, there is no

reason to have them redrawn along with the rest of the window.

The goodRgn is subtracted from the updateRgn of the current GrafPort.

Using this call to reduce the amount to redrawing will have a significant

effect on the perceived speed of an application.

Use ValidRect to perform this same service, but for a rectangular region

(save the overhead of creating and disposing the region, etc.).

Referenced by (9):