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From: lsr@Apple.COM (Larry Rosenstein)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Text Drawing at speeds greater than 1200baud
Message-ID: <464@internal.Apple.COM>
Date: 23 Jan 89 18:18:36 GMT
References: <2243@uokmax.UUCP> <27572@ucbvax.BERKELEY.EDU> <18791@santra.UUCP>
Organization: Advanced Technology Group, Apple Computer
Lines: 22

In article <18791@santra.UUCP> jmunkki@kampi.UUCP (Juri Munkki) writes:
>
>No objections here. I do not restrain my windows, but the effect on speed
>is visible on a MacPlus. This is because I use an offscreen bitmap to
>contain my text screens. If the bitmap and the window are not exactly
>aligned, QD has to do a lot of bit-shifting.  Zooming the window positions
>it intelligently to a word boundary (I plan to document this feature in the
>manual).

One thing to try is to shift the offscreen bitmap so that it is always
aligned to the screen.  You can do this with a CopyBits call, or write some
custom code.

You only need to do this when the window moves or scrolls horizontally.  For
a full MacPaint-size page this takes .5 seconds on a Mac Plus.  For a
terminal screen, it should be faster.

-- 
		 Larry Rosenstein,  Object Specialist
 Apple Computer, Inc.  20525 Mariani Ave, MS 46-B  Cupertino, CA 95014
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