LockWindowUpdate

Am I getting no reply because no one knows about the API?

Jonathan

I found this article online concerning the LockWindowUpdate API, and it said the following:

"MS does not recommend the use of the LockWindowUpdate API function for preventing drawing to a specific window while multiple updates are occurring. The preferred method is to use the the SendMessage API function along with the WM_SETREDRAW constant passing the hWnd of the specific window that should not be redrawn."

Is SendMessage better (faster) than LockWindowUpdate?


Jonathan

Thanks, this helped alot.

But I do have one more question. If using LockWindowUpdate API is bad, how do you avoid multiple refreshed of a specific hdc when you have more than one drawing routines?

Say we are using a picturebox, the only manner I have found to make the drawing operation stay for the duration of one frame when invoking Bitblt (for example) is by setting the AutoRedraw bool to true. Is there then a faster way?

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quote:

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Original post by Anonymous Poster
if the memory bitmap is too big to blit all at once and stay within some pre-defined speed requirements, then a technique called dirty rectangles could be used to blit only those portions which have changed to the device DC.

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When do I know when the memory bitmap is too big?



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