On 6/1/05, Andy Goth <[EMAIL PROTECTED]> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Timothy Miller wrote: > > On 6/1/05, Andy Goth <[EMAIL PROTECTED]> wrote: > > > I have a relatively slow display on my laptop (have to use VESA > > > drivers), but I only notice when I scroll a lot of text in a > > > vertically-maximized xterm. The rest of the time, things are peachy. > > > > Good point. I hadn't thought of that. > > > > But in his defense, if there are lots of blank spaces on the screen, > > and they're in many of the same places before and after the scroll, > > then it's not so bad. Of course, we can't always count on that sort > > of thing. > > I was going to say that I've seen some xterms try to scroll everything, > even the blank spaces, and I've seen other xterms only scroll the > regions with text. Wait, not quite. Rather, if the xterm were going to > scroll "aaa" to the right, it would erase the first "a", leave the next > two untouched, and draw a new "a" at the right. > > But then I remembered that this goes in hardware, so "smart" and > "stupid" programs alike will get the same treatment, and the concern > isn't over which memory addresses have been touched, but which have > actually changed. > > You (plural) seem to believe that the screen update will take variadic > time as a function of the number of memory addresses that have changed > (or blinked). Will this non-constant frame rate complicate things?
No, although I don't plan on doing it this way. I mean, it's not a bad idea... I just don't see it as necessary, and I don't want to hurt the performance of the worst case. > Will there be a double buffer involved, or is it acceptable for the > monitor to briefly display the partially-updated screen? That's a whole other issue. You can get a "tearing" effect when updates are not in sync with the video, but this is no different from dragging a window around on the screen that isn't frame-synced. At Tech Source, we've had to deal with a number of different situations where we had to eliminate tearing, but these were cases where the tear line was constant, nearly constant, or diagonal. In those cases, you can see it clearly, and it's disturbing. For OGP purposes, however, tearing isn't much of a concern, although we should make frame-sync optional in case we can be sure the conversion happens in less than one video frame. But what are the chances we can do that? _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
