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From: erics@eleazar.dartmouth.edu (Eric Schlegel)
Newsgroups: comp.sys.mac.programmer
Subject: offscreen PixMaps and GDevices
Message-ID: <10054@dartvax.Dartmouth.EDU>
Date: 13 Sep 88 02:06:49 GMT
Sender: news@dartvax.Dartmouth.EDU
Reply-To: erics@eleazar.dartmouth.edu (Eric Schlegel)
Organization: Dartmouth College, Hanover, NH
Lines: 22
References:

A question to color QD gurus:
I'm trying to draw onto an offscreen pixMap with color QD, and later copyBits
this pixMap back to a window. This is fairly standard, and Tech Note 120 gives
a simply example. TN120 gets the max depth device, sets theGDevice to that max
device, creates a port, draws into it, restores the old gdevice, and copyBits
to a window. What I want to do is create an offscreen port for the max depth
device also. However, I also want to draw into this port at a later time when
the max depth device may have changed. My question: can I still set theGDevice
to the original max depth device and have the offscreen draw work, even if,
say, the depth or color table of the max device has changed? Or do I need
to create my own offscreen gDevice that I know won't change?

IM V mentions problems with copyBitsing from an offscreen port to a changing
destination device (p. V-126). I understand this problem. But I can find
no references to what you should do if the source (max) device changes and you
want to redraw the offscreen port.

Any help is appreciated... Eric

------
Eric Schlegel                 |  DISCLAIMER: I'm just a poor college student,
eric.schlegel@dartmouth.edu   |  which means I'm not responsible for what I
                              |  say and I can't pay you if you sue me anyway.