How do I draw a blue rectangle with a alpha/transparency value of 0.5 (ie, 50% transparency) in Native Win32 C++?
Using a macro like RGBA() fails, I’m not sure how I can specify the alpha value of the brush.
SetDCPenColor(hdc, RGBA(255,255,0,127));
SetDCBrushColor(hdc, RGBA(255,255,0,127));
Rectangle(hdc, 0, 0, width, height);
You need to use the AlphaBlend function –
http://msdn.microsoft.com/en-us/library/windows/desktop/dd183351(v=vs.85).aspx
http://www.codeproject.com/Articles/286/Using-the-AlphaBlend-function