Need help BITBLTing XOR rops between 2 picture boxes

[ShepherdOfChaos]

I think I must be missing something here. What I'm trying to do is:

BitBlt(picDestination.hdc,0,0,width,height,picSource.hdc,0,0,SRCINVERT)

SRCINVERT is (or should be) a XOR operation.

My two pictures are almost identical, with just a few areas that have changed. The purpose of XORing the two is to isolate the areas that have changed, and get rid of areas that are the same.

However, when I do the above with my two picture boxes, it looks as though the source is simply being copied (SRCCOPY) into the destination instead of being XORed.

Is there some property of my picture boxes which is preventing the XOR operation? Any clues?

[ShepherdOfChaos]

Yep. I was missing something alright

I was missing the .hdc on picSource above, so the BitBlt function was simply failing.

Got that fixed and XOR's work just fine with pic boxes (and I feel silly :0 )