Hi I'm writing a client/server remote viewer application where screenshots of the desktop are sent across the network over a socket. I'd like to reduce the size of the transfer by getting the difference between the two images and then sending the difference. The difference would be at least a rectangle, no? So I need to locate where the change is and send only the "update rectangle" to the client.
How can I do that? I need performance... (can't loop through pixels... too much time consuming)