4225_5117@uwovax.uwo.ca (03/05/91)
I'm looking for some suggestions regarding a programming problem we've run
up against here. We are writing a program that does horizontal panning on the
graphics screen, so the only way we could get the speed we needed was to use
the horizontal pel panning register in conjunction with the start address
register of the graphics controller. If there is another way to achieve the
same speed, please let me know, but for now I'll assume it's the only way.
Now the problem I'm having is that I want to draw just off the side of
the screen that is about to come on so as to have the appearance of continuous
data. I've set the screen width to 82 bytes wide, and I know that is do
properly as the BIOS draw routine works OK (but it is, of course, FAR too
slow). But the MicroSoft C graphics library seem to assume that the screen is
only 80 bytes wide and draw everything in the wrong place. Even the BIOS
routines fail to draw in the proper place if the screen start address is not at
the start of an even page.
So my question is, has anyone else had experience doing this sort of thing,
and is there anyway to either get the MicroSoft routines to work, or substitute
another graphics library that will do what we want. If not, it looks like
we'll have to write our own drawing routines, which we obviously would rather
not do.
Any sugeestions would be appreciated. Please reply by email but if anyone
else wants to hear about my results, I will post a summary later. Thanks in
advance.
Mike Hackett (University of Western Ontario)
4225_5117@uwovax.uwo.ca