| You are probably running on a GPX and probably each pixmap is bigger than half
the screen. The problem is that pixmaps have to be paged into the GPX's off-
screen memory to be written to. If you are getting exposures and thus reading
from one pixmap, and are trying to write to the other at the "same" time, you
are probably thrashing like mad. At the very least, the writing pixmap stays
in, but the reading pixmap is brought in a few lines at a time, which ties up
the server and keeps you from writing.
In other words, it is probably not the iconification per se, but the exposures
on the other window.
BTW, before you say "It can't be *that* slow"...yes it can. The GPX is TERRIBLE
at getting data moved to and from virtual memory.
There is little you can do except to either cut down the size of your pixmaps
or try to use only one pixmap at a time. It's a hardware limitation
unfortunately. You should see it significantly better on a monochrome system
(which keeps all pixmaps in virtual memory) or on an SPX system (which has a
lot more offscreen memory and can pack it more efficiently).
Burns
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<You are probably running on a GPX and probably each pixmap is bigger>
<than half the screen. The problem is that pixmaps have to be paged >
<into the GPX's off-screen memory to be written to. >
Yes and no. Your assumption about my pixmpas is 100% correct. I have two
pixmaps, and each is larger than half the screen. I'm not running on a GPX
though. My application is running on a VAXstation 3100. By chance, do you
know if this 'problem' also exists on the VAXstation 3100?
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<If you are getting exposures and thus reading from one pixmap, and are >
<trying to write to the other at the "same" time, you are probably >
<thrashing like mad. At the very least, the writing pixmap stays in, >
<but the reading pixmap is brought in a few lines at a time, which ties >
<up the server and keeps you from writing. >
From what I understand about exposure events, and when they occur, I
don't believe this is the case, but I may be wrong (I'll take a much
closer look at it - Thanks). The window I'm writing to is 'on top' of the
other, and the other window is just sitting there minding its own business.
Wouldn't I have to be moving windows around (exposing pieces of the 'other'
window) for it to encounter exposures? If I'm correct, and expsoures are
not occuring, do you know of anything else that could be causing this strange
behaviour?
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P.S. Thank-you for the info. I appreciate it!
|
| The GPX is a graphics processor, which is independent of the VAX processor.
Most VAXstation 3100s come with a GPX. For comparison, the SPX is a faster
graphics processor that can also be used with a VAXstation 3100.
The GPX has the same characteristics no matter which VAX processor it is
connected to.
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