tek@CS.UCLA.EDU (02/01/89)
Suppose you have an application that uses two windows. One top-level
window and a subwindow. The subwindow must satisfy some set of
constraints on its position and size in the top-level window. Now
suppose you resize the top-level window:
from this: to this:
+-------+ +---------------+
#1: | | #2: | |
| +-+ | | +-+ |
| | | | | | | |
| +-+ | | +-+ |
| | | |
+-------+ | |
| |
| |
| |
| |
| |
+---------------+
now, of course, you want to resize and move the subwindow to this:
+---------------+
#3: | |
| |
| |
| +---+ |
| | | |
| | | |
| | | |
| +---+ |
| |
| |
| |
+---------------+
Let's assume there is no backing store, no gravity and that expose
is selected on both windows. Now, when going from #1 to #2, you get a
series of exposure events on the top-level window. Then, when you go
from #2 to #3, you get a series of exposure events on the top-level
window and the subwindow.
A "smart" application that knew what was in each region in the window
would not redraw anything twice in this sequence. But a "dumb" one,
which redraws everything on an exposure, would redraw the top-level
window twice (skipping all non-zero count exposure events).
Is there any technique, one can use to prevent the "dumb" version from
redrawing the top-level window more than once?
Is there a way of recognizing all the exposures as part of the same
"macro" event, without possibly missing an exposures due to outside
interference?
My apologies, if this has been discussed before ...
Ted Kim ARPAnet: tek@penzance.cs.ucla.edu
UCLA Computer Science Department UUCP: ...!ucbvax!cs.ucla.edu!tek
3804C Boelter Hall PHONE: (213) 206-8696
Los Angeles, CA 90024 ESPnet: tek@ouija.boardrws@EXPO.LCS.MIT.EDU (Bob Scheifler) (02/01/89)
Is there any technique, one can use to prevent the "dumb" version from
redrawing the top-level window more than once?
You could set Unmap win-gravity on the child. When the parent is resized,
the child will get unmapped, and the parent will repaint. Reconfigure
the child, and then map it again. The parent will not get further exposures.
Is there a way of recognizing all the exposures as part of the same
"macro" event, without possibly missing an exposures due to outside
interference?
I'm not sure what you mean by "macro" event.