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From: lsr@apple.UUCP
Newsgroups: comp.sys.mac
Subject: Re: What makes programming the Mac difficult?
Message-ID: <1082@apple.UUCP>
Date: Wed, 17-Jun-87 18:30:18 EDT
Article-I.D.: apple.1082
Posted: Wed Jun 17 18:30:18 1987
Date-Received: Fri, 19-Jun-87 05:42:10 EDT
References: <869@apple.UUCP> <1499@midas.TEK.COM> <981@apple.UUCP> <1506@midas.TEK.COM>
Reply-To: lsr@apple.UUCP (Larry Rosenstein)
Organization: Advanced Technology Group, Apple Computer
Lines: 26

In article <1506@midas.TEK.COM> herbw@midas.TEK.COM (Herb Weiner) writes:
>In article <1499@midas.TEK.COM> I wrote:
>>2.  I want to do a CopyBits of more than 3K bytes.  I must write a loop to do
>>    this.  Why couldn't the toolbox routine include a check for the 3K limit
>
>I therefore offer the following quote from Inside Mac, Page I-188, as part
>of the description of CopyBits (*not* OpenPicture):
>"Warning: The source bit map must not occupy more memory than half the
>available stack space.  A good rule of thumb is not to copy more than
>3K bytes."

I talked to someone in Tech Support about this to get a definitive answer.
He thought that the 3K rule was a holdover from the days of 128K Macs, when
there wasn't much stack space.  He also thought that CopyBits only needs
lots of stack space when the bitmap is being stretched (ie, source and
destination rectangles are not the same size).

-- 
Larry Rosenstein

Object Specialist
Apple Computer

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