which message/event to use

[alexfreed58]

I have a dialog (using MFC) that needs to paint a few child windows and then grab the bits from the result and copy to another window. I found some examples for saving the bits, but I'm not sure how to determine the moment when all the child windows have been painted. Right now I set a short timer after invalidating the last child window and do the BitBlt when it expires. Works, but doesn't seem right. I tried to use Spy++ to see if the main window gets any interesting messages, but found none. Anybody?

Thanks.

[kbw]

You request an area to be painted by marking regions with InvalidateRect. The areas are painted on WM_PAINT. But that's a low priority message, in that they may be pushed back in the message queue, and they're coalesced.

[alexfreed58]

I did InvalidateRect to update the child windows. My question is how to determine a moment that they (custom controls) all finished drawing. Send a custom message from each to the mother window? Once again I have no problem updating everything. I just need to know when it's finished.

[kbw]

It happens in response to the WM_PAINT. There is no further notification.