warlock@csuchico.edu (John Kennedy) (03/07/90)
I got some mail telling me that I was less than clear with my problem, so I decided to take another stab at describing it for everyone else. Pieces of my letter follow: My problems start when a X-window obscures part of my altered area. When I alter the screen directly by mmaping the frame buffer, the server's idea of the screen no longer matches reality. This is fine, except that pop-up windows occassionally obscure part of the screen that I have altered. When X attempts to refresh that section of screen (expose events), it is done "incorrectly". By incorrectly, it updates what it thinks is there, which is not what I want. I want it to refresh the screen with what was on the screen after I finished my low-level drawing. I figured the best way to do this would be to make a copy of the section of screen that I had altered and store it in the pixmap of the X-window, the goal being that X would now have the "correct" image. The method of doing it would be to save the altered area just before anything that would obscure part of it would be called. But how to do it? THAT is the question. (-: As for slowness, the area of memory that I'm altering is a 768x768 chunk of screen. I'm using over 128 different colors in the process of plotting a giant ppi (rather like a color version of the radar displays you see in air-traffic controller's towers). With a sweeparm that doesn't hose the data, mind you, I'm attempting to get over 20 RPM out of a Sun 3/60 using a cgfour. I've got 21 RPM at the moment, which I happen to feel is a miracle. Sun originally claimed that we (our company) could use SunView to plot these points (there are over 58000 points per section, 8 sections total). Speed is a very relative thing! (-: -------------- The only incorrect bit of info was that there are over 73000 pixels to be plotted. -- Warlock, AKA +---------------------------------------------------- John Kennedy | uucp: lampoon!warlock@csuchico.edu CSCI Student | internet: warlock@csuchico.edu CSU Chico +----------------------------------------------------