[RESOLVED] Capture a screen area underneath a Form

[boops boops]

Thanks for the suggestion McBluffin. I wondered about PrintWindow but I clearly needed to capture the whole stack of windows under the form including transparent ones.

Anyway, it turns out that the failure of BitBlt + SrcCopy Or CaptureBlt wasn't a matter of web content. It only happens with the VS2008 WebBrowser (Version 2.something) which I was using and not to FireFox, IE7 or anthing else I have tried. The WebBrowser in VS2010 (Version 4.something) is also okay and so is WPF.

I suppose I can live without capturing WebBrowser2 displays and their ilk. Still, I wonder how it is that Graphics.CopyFromscreen, which is supposed to be a managed wrapper for BitBlt, does succeed in capturing the blighters?

Now I realise that the problem of having to hide the part of the form over the area captured is largely a question of design. So I can consider this thread resolved.

EDIT: by the way, both BitBlt with CaptureBlt and CopyFromScreen work in their own way with layered windows with per-pixel alpha. CaptureBlt captures everything, CopyFromScreen ignores pixels with alpha < 255.

Thanks all for your help. BB