Windows Vista and Windows 7 display semi-transparent forms when Aero is activated. And some screen-taking applications such as WinSnap or Windows Clippings are able to capture those windows as a semi-transparent PNG image. What Windows API are they using to obtain such a beautiful capture ?
A:
There isn't any, to my knowledge. If you look closely, at least WindowClippings takes two separate screenshots. One with white background and one with black background. It then uses those two screenshots to calculate the transparency of the glass pixels.
Joey
2009-10-05 14:09:44
This is an amazing idea and seems to be the trick. I've made a search based on your answer and found out that Blog post which explains the process: http://www.interact-sw.co.uk/iangblog/2007/01/30/recoveralphaToo bad Microsoft didn't provide any API for it though. Thank you very much for your fast answer Johannes!
John Riche
2009-10-05 14:30:03