C\C++ - win32: can i copy the parent background?

[Cambalinho]

we have a child control on parent. can i copy what is on parent background, where is the child control?
i used the BitBlt() but i get a black rectangle. i don't belive the parent eliminates the parent background, where is the child control.
can anyone advice me?

[kbw]

Are you implementing transparency?

[Cambalinho]

too ;)
but i need copy the parent background for do the job(and use the AlphaBlend() function too)

[kbw]

It's just a matter of passing in the parent's window handle

I can't remember the call, but I had it all worked out at some point. There's a sample project here that you look at. https://code.msdn.microsoft.com/windowsapps/How-to-add-wartermark-f6313fad