Qt multi purpose capture window
I want to write a capture window in C++ and Qt, which can display any other window's contents and also video feed from a webcam, a tv stream etc. (I want to be able to overlay several sources later on). Could anybody point out how to do this in general and which classes and techniques I should research? Thanks in advance.
It would also be interesting to know how to implement pie menus. Does anybody know how to do this most effectively?