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From: kaufman@polya.Stanford.EDU (Marc T. Kaufman)
Newsgroups: comp.sys.mac.programmer
Subject: Quickdraw Bug
Message-ID: <3174@polya.Stanford.EDU>
Date: 6 Jul 88 15:58:04 GMT
Reply-To: kaufman@polya.Stanford.EDU (Marc T. Kaufman)
Organization: Stanford University
Lines: 10

FYI: I have uncovered a bug in Quickdraw that can trash memory.
Environment:  8-bit pixel, rowbytes > 4000 (e.g. 6000).  Draw a line from
above the pixmap to below the pixmap, going through the pixmap.  Quickdraw
will set pixels in the row [portRect.top -1].  If the portPixMap is not enough
bigger than the portRect to contain the extra row at the top, these pixels
are set on whatever happens to be in memory... (such as your code).

Just thought you all would like to know.

Marc Kaufman (kaufman@polya.stanford.edu)