The aim of this article is not to present you how to prevent your Windows program from flickering, just show a little trick that will help you avoid flickering on parent window created without WS_CLIPCHILDREN.

By default, main window will be created with WS_CLIPCHILDREN mask, that prevents child controls on the parent window from being painted twice. As we know, flickering comes from drawing a pixel twice, so WS_CLIPCHILDREN will greatly reduce flickering.

But, WS_CLIPCHILDREN will cause another annoying problem, “child control dark block”, if you’ve never heard of it, try to create a windows program with WS_CLIPCHILDREN mask, and place 3-5 Edit and Static Text controls on main window, compile and run it, then minimize and restore it repeatedly. You’ll probably see on-screen “child control dark block” on these child controls.

Finally I found a way to avoid flickering without WS_CLIPCHILDREN. The key is ExcludeClipRect function.

Assuming that you have a main window created without WS_CLIPCHILDREN mask, and four Static controls on it, Static A is for owner drawing, the other three are for static text display. Normally, there’ll be flicker on Static A when you moving the window out of the screen. Now what we need to do is add WM_ERASEBKGND handler in main window message loop.

the code above will exclude Static A from repaint area, so you can process Static A owner drawing in custom code (we’re subclassing Static A).

Now, even not using double-buffing, we can get smooth owner drawn Static without flickering. But it’s still a median way, the best solution is building gui controls from scratch, and create main window with WS_CLIPCHILDREN, child controls will have their own message procedure and owner drawing code. A good example of how to create custom control is SpinCube control from the latest Windows SDK.