[comp.sys.mac.programmer] Are there limits on Quickdraw picture sizes?

seiler@amarna.gsfc.nasa.gov (Ed Seiler) (06/06/90)

After a great deal of playing around, the problem I had trying to create a
QuickDraw picture via OpenPicture, CopyBits, and ClosePicture (see postings on
"Need help creating a QuickDraw picture" and "Still need help...") seems to
reduce to the fact that I was starting with a 512x512x8-bit pixel map, and
trying to create a QuickDraw picture with a single CopyBits call for the entire
pixel map. If I restrict myself to say a 512x64 section, it works fine. So is
it impossible to do it all in one shot? I am sure that DrawPicture can handle
pictures that big, that is pictures bounded by a single box rather than a
series of horizontal strips. So why can't the OpenPicture process handle them?
It seems to me that if it relies on stack space, and runs out in the process,
it could very well break the picture into strips itself.
  I think I have checked everything else, such as adjusting the clipping
region, etc. I have received some replies expressing doubts that CopyBitsing
with the same source and destination pixMaps will generate QuickDraw commands;
however that is not the case, i.e. you CAN use the same source and destination.
QuickDraw doesn't insist that such an operation is pointless, probably for the
very reason of doing it to create a picture.
  Certainly there must be those of you out there who have done what I am trying
to do (is there any other simple way to take a pixel map and save it as a PICT
file?) Any comments or suggestions would be appreciated.

Edward Seiler                           seiler@dftnic.gsfc.nasa.gov
Mail Code 635                           seiler@chrpserv.gsfc.nasa.gov
Goddard Space Flight Center             (301) 286-9421
Greenbelt, MD 20771

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