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From: tisu@quads.uchicago.edu (seth alan tisue)
Newsgroups: comp.sys.mac.apps
Subject: Re: ATM screen performance on low-end Mac's?
Message-ID: <1991Feb13.003707.20132@midway.uchicago.edu>
Date: 13 Feb 91 00:37:07 GMT
References: <146099.27B389C9@cmhgate.FIDONET.ORG>
Sender: Seth Tisue (tisu@midway.uchicago.edu)
Organization: University of Chicago
Lines: 32

In article <146099.27B389C9@cmhgate.FIDONET.ORG> Michael.Burton@p3.f200.n226.z1.FIDONET.ORG (Michael Burton) writes:

>   ATM keeps the screen bitmaps it creates in a buffer.  If the buffer is
>too small, ATM will have to re-create the screen bitmaps more often,
>slowing performance.  Large type sizes occupy more buffer space than
>smaller sizes.  Using a large number of fonts will also tend to fill up
>the buffer more quickly.
>   You can control the size of ATM's buffer in the Control Panel.
>   After adjusting to the delay in changing font, size or style, I've
>found that ATM provides satisfactory speed even on my Mac Plus.

I use an SE/30, so the bitmap-generating delays are less, but they are still
definitely noticeable (2-5 seconds); also note that separate bitmaps must
be generated for all the different styles (normal, bold, italic, bold/italic)
of a font.

This delay is no problem under ordinary circumstances, but if you're working
with a document with many different fonts, and a small buffer size, it's
possible to have programs like PageMaker slow down to a complete crawl --
I mention page-layout programs in particular, since with those you frequently
change views (100%, 200%, etc.), which requires generating new bitmaps.

Sum: ATM's fine unless you're working with a bunch of different fonts (say,
more than three) in different sizes -- and even then, you can make the problem
lessen if you've got lots of memory to give ATM.



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Seth Tisue  (tisu@midway.uchicago.edu                 P.O. Box 5975
University of Chicago                              Chicago IL 60680