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From: dale@amiga.UUCP (Dale Luck)
Newsgroups: comp.sys.amiga
Subject: re: layers and cliprects
Message-ID: <1697@amiga.amiga.UUCP>
Date: Thu, 2-Jul-87 01:48:54 EDT
Article-I.D.: amiga.1697
Posted: Thu Jul  2 01:48:54 1987
Date-Received: Sat, 4-Jul-87 04:17:35 EDT
Reply-To: dale@amiga.UUCP (Dale Luck)
Distribution: na
Organization: Commodore-Amiga Inc., 16795 Lark Ave. Suite 106, Los Gatos CA 95030
Lines: 35


<< The problem is that if you have a bunch of smart-refresh windows on the
<< screen, and do much window manipulation, they each get chopped up into a
<< whole bunch of super-small bitmaps and updating becomes pure agony. Simple
<< refresh is slightly (slightly! If you use a single Text() call for each
<< line of text you output, it's damn fast) slower for the simple case, but
<< its behaviour doesn't degrade nearly as badly.
The number of Cliprects in a smart layer or simple refresh is the same.
The difference is whether there is a bitmap allocated for the obscured
cliprects. The unobscured cliprects bitmap pointer point to the shared
bitmap. So the speed up you see is it just not writing into the nonexistent
background buffers.

<To toss an obvious idea out...  how about a priority -200 task that coagulates/
<optimizes cliprects and frees the extra chip memory taken up by the above
<situation?

The Cliprects are coagulated after ever internal delete layer operation.
MoveLayer and SizeLayer both use internal delete.
This, besides delete layer is the only time it makes sense to try to combine
obscured cliprects. The only thing that prevents completion of the dedicer
is memory constraints. poof. If it cannot find the necessary amount of bits in
the right size chunks it gives up and tries again the next time.

Whenever any operation that affects the topography of the shared screen
happens, it recalculates what it thinks is an optimal set of cliprects
for that topography.

Your lucky now, you should have seen it before I write the dedicer, If you had
two windows up and just moved the window that was on top down 10 times in
small increments, it just kept breaking those little cliprects up into
smaller and more pieces. You don't see that now, so it must be doing
something.

Dale Luckm