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From: francis@daisy.uchicago.edu (Francis Stracke)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Large Offscreen Drawing - help please
Message-ID: <1990Nov19.205344.9317@midway.uchicago.edu>
Date: 19 Nov 90 20:53:44 GMT
References: <11722@hubcap.clemson.edu>
Sender: news@midway.uchicago.edu (News Administrator)
Organization: Mathematics Department, University of Chicago
Lines: 17

In article <11722@hubcap.clemson.edu> jcocon@hubcap.clemson.edu (james c oconnor) writes:
>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?

Isn't that enough? Have you thought about just how huge this is?
RowBytes=2000, for God's sake! This means you would need 32G to hold
the damned thing! If you've got 32 gigabytes in your Mac, please
tell me what decade you're going to buy it!
| Francis Stracke		| My opinions are my own.  I don't steal them.|
| Department of Mathematics	|=============================================|
| University of Chicago		| Non sequiturs make me eat lampshades	      |
| francis@zaphod.uchicago.edu	|   				       	      |