Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!batcomputer!cornell!uw-beaver!ubc-cs!van-bc!rsoft!mindlink!a347
From: John_Miller@mindlink.UUCP (John Miller)
Newsgroups: comp.sys.mac.programmer
Subject: Re: patching bottlenecks
Message-ID: <5370@mindlink.UUCP>
Date: 2 Apr 91 01:34:48 GMT
Organization: MIND LINK! - British Columbia, Canada
Lines: 22

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?

HyperCard seems to patch the bottlenecks to maintain consistency
between the off-screen bitmap and the displayed card window.
Each of the low level graphic routines draw into the off-screen
bitmap and then copybits the result to the screen.

I don't know about LineTo, but I do know that HyperCard is doing
this for things like inverting rectangles.

______________________________________________________________________
John Miller                         (604) 433-1795
Symplex Systems                     AppleLink (???)  CDA0461
Burnaby, British Columbia           Fax: (604) 430-8516
Canada                              usenet:  john_miller@mindlink.uucp

Macintosh Consulting and Software Development
______________________________________________________________________