Path: utzoo!utdoe!generic!pnet91!taob
From: taob@pnet91.cts.com (Brian Tao)
Newsgroups: comp.sys.apple2
Subject: 64K graphic limit
Message-ID: <542@generic.UUCP>
Date: 27 Feb 91 05:15:50 GMT
Sender: root@generic.UUCP
Organization: People-Net [pnet91], Etobicoke, ON
Lines: 18

From daveh@ccwf.cc.utexas.edu (Daid H. Huang):

> QuickDraw II is supposed to handle "pictures" (I forgot the exact term
> for it) up to 32768x32768. APF doesn't put a limit on the picture size
> either. I think the reason for the 64K limit is that it's hard to
> manipulate data that crosses a bank boundary, especially in C.

    I'm sure a reasonable comptent programmer should be able to write some
code which will swap memory in an out of video RAM for large pictures.  I
thought GS/OS calls treat the GS's entire memory space as one contiguous
address, with the end of one bank wrapping over to the beginning of the next
bank.  There is a file called BIGPICTURE in the GS file section in CompuServe
which sounds interesting.  I saw it in the new uploads list of a local BBS,
but I haven't been able to find the actual file.  Maybe someone _has_ figured
out a way around the 64K limit.

Brian T. Tao   *B-) |  t569taob@bluffs.scar.utoronto.ca  | "Though this be
U of Metro Toronto  |               - or -               |  madness, yet there
Scarberia, ON       |        taob@pnet91.cts.com         |  is method in 't."