roman@ATHENA.MIT.EDU (04/24/87)
Besides problems already mentioned one area where GKS doesn't fit easily to X is user input. General problem is that the implementation level 2b (available from Visual Engineering) doesn't support asynchronous input ( a request for mouse input blocks until a mouse button is hit). This makes building user interfaces based on GKS difficult. I don't know of any higher level implementation. Specific problems with VE implementation is that the notion of connection they use (Unix file descriptor) doesn't apply to X (where you have to use Xlib functions to read input). As a result they read alpha input from the stdin and not from GKS window. We are considering setting up the X driver such that GKS would do output to a given X window (there is no clean way of doing this within GKS standard). This would make possible applications where interface is built using xtoolkit and GKS uses one (or more) subwindows. You can mail inquires about details of our port of VE GKS on X to me. Roman. roman@athena.mit.edu