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From: time@ice.com (Tim Endres)
Newsgroups: comp.sys.mac.programmer
Subject: Re: patching bottlenecks
Date: Tue, 2 Apr 91 21:19:49 EST
Organization: ICE Engineering, Inc.
Message-ID: <1CE00001.bokfpfm@tbomb.ice.com>
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In article <70621@brunix.UUCP>, reb@cs.brown.edu (Robert E. Brown) writes:
> How often and for what reasons do programs patch the Quickdraw bottlenecks?
> I know printing causes them to be patched, but under what other circumstances
> is patching appropriate?
> 
> The only example I have seen is that of a program that wants to resize a
> PICT but leave line-widths unchanged.
> 
> Why else would one want to patch something like LineTo?

Possibly to write translators from QD to other formats. In fact I
knew of a system that trapped QD and output IGES (CAD Exhchange).

Another reason commonly employed was to trap drawstrings to get tabs
correctly in Text Edit views.

At U of M CITI we used the routines to display Macintosh applications
on Apollo workstations by sending the traps across TCP. I also suspect
that some of these programs like Timbuktu may also trap the QD routines
to get their functionality, but I am not sure.

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