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From: jcocon@hubcap.clemson.edu (james c oconnor)
Newsgroups: comp.sys.mac.programmer
Subject: Large Offscreen Drawing - help please
Message-ID: <11722@hubcap.clemson.edu>
Date: 19 Nov 90 19:27:55 GMT
Organization: Clemson University, Clemson, SC
Lines: 9

A friend and I are fiddling around with off screen drawing to give zooms
and fast scrolling on some graphical data.  On the zoom, we allocate a
huge bitmap (16,000 by 16,000) on an offscreen port.  We then call eraseRect
on the (0,0) and (16000,16000), but it only clears the upper left corner
of the bitmap, and scrolling around shows dirty memory.  Aside from the
wisdom of allocating such a large block of memory (we are PLAYING), is there
something we are missing?

Jim