Newsgroups: comp.sys.amiga.programmer
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From: rjc@geech.gnu.ai.mit.edu (Ray Cromwell)
Subject: Re: quasi WB2.0 BUGS
Message-ID: <1991Mar27.081942.3874@mintaka.lcs.mit.edu>
Sender: daemon@mintaka.lcs.mit.edu (Lucifer Maleficius)
Organization: The Internet
References: <3877@bruce.cs.monash.OZ.AU> <20150@cbmvax.commodore.com>
Distribution: comp.sys.amiga.programmer
Date: Wed, 27 Mar 91 08:19:42 GMT
Lines: 65

In article <20150@cbmvax.commodore.com> jesup@cbmvax.commodore.com (Randell Jesup) writes:
>In article <3877@bruce.cs.monash.OZ.AU> roddi@bruce.cs.monash.OZ.AU (Roddi Walker) writes:
>>	I was at a developer friend's house a few days ago, playing with
>>WB 2.0.  While it is a huge advance over 1.3, I notices a few nasty things
>>happen when fooling around with 10-20 windows, all roughly stacked over each
>>other.
>
>	Note that the release is likely to considerably different than a
>developer-only beta.
>
>>	First, the updates are SSLLLOOOOOOWWWWWWW - if I close/move/whatever
>>a window, I have to wait 10+ seconds for the mouse to unfreeze and the
>>update/redraw to finish.  It was this slow in 1.3, but I had hoped things
>>would have sped up under 2.0 (this is on a 68000 A2000 with lots of ram,
>>btw).  True, people normally fool around with 1-7 (say) windows, but this
>>is a nasty limitation.  Just out of interest, I tried the same thing on
>>a nasty 8MHz 68000 Mac Plus, and its performance (for window redrawing)
>>was MUCH BETTER - Not appreciably slower than when it was redrawing
>>just a couple of windows.  I would guess that the Mac uses a much smarter
>>algorithm - not only is it unquestionably MUCH faster, but I also don't
>>see poorly refreshed windows on the Mac as I do under WB 1.3 (sometimes).
>
>	What's really going on here is that the mac doesn't allow anything
>to draw into an unexposed window (notice how windows pop to the front when
>you activate them?)  So it doesn't have to save off-screen bitmaps, and doesn't
>have to worry much about clipping rectangles - only visible portions count.
>Also, work has been done on layers to improve performance (and it has been
>improved considerably from earlier 2.0 versions), but the basic algorithms
>required to handle multitasking, (partially) obscured windows have an 
>exponential component in the recalculation of the clipping rectangles.
>
>>	Also, when 2.0 was redrawing the windoes, it would often leave
>>vertical/horizontal 1 pixel wide/thick gaps when redrawing the window
>>borders (the box with the scroll bars) and the little rectangle around the
>>icons within the window.
>
>	I haven't seen anything like this (if I read it right, it's confusingly
>worded) in any recent version.

   I have a suggestion. How about a new layer type called DUMB_REFRESH.
DUMB_REFRESH layers would store the entire window offscreen instead of
just the hidden parts. Intuition should  use DUMB_REFRESH windows
as default until a memory pannic(AllocMem()) occurs, then intuition would
convert a few DUMB layers into SIMPLE/SMART ;layers.

  The Mac's system is less memory efficient, but faster. I feel
the AMiga should offer both. Speed, and then memory efficiency.
You could also make DUMB_REFRESH a preferences option, and people with
gobs ram  could opt to activate it.

 I don't know how cuts/clipping of dumb layers would work tho.

OA>-- 
>Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
>{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
>Thus spake the Master Ninjei: "To program a million-line operating system
>is easy, to change a man's temperament is more difficult."
>(From "The Zen of Programming")  ;-)


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|n|   rjc@albert.ai.mit.edu   Amiga, the computer for the creative mind.  |n|
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