Alpha-blended fade when showing a full screen window

[ber4444]

I have Qt (the latest version from Git) configured with -sdk macosx10.10
What I want to achieve is this: http://stackoverflow.com/questions/7648952 perhaps using the native Media layer on OS X (initially that's my target platform and speed is the first consideration, not portability).
Two parts of the question:

1. how to make a full screen translucent window that covers all monitors and virtual desktops, including the upper menu bar and the dock (the app called "Time Out Free" seems to have done that but it's not open source)
2. how to make a smooth fade-in animation of this window (the window has an opaque image and translucent color around it)