I was reading the source code of the file GetImage.c and got confused about the
function XGetImage. Specifically, I'm confused about where the defined variable
register xGetImageReq *req; is used. The function never uses it again after
setting values for req at line 83. At line 85, does the function _XReply copy
the whole display/screen's data to rep or just the specified rectangle defined
by req? If _XReply copies the whole display/screen's data, where does the
function XGetImage crop the image to keep the specified rectangle only?
