tim@efi.com (Tim Maroney) (07/24/90)
I am working on an application that requires offscreen pixmaps in which the baseAddr field gets changed frequently to point to pixel buffers the application is managing. Offscreen pixmap support in 32-bit Quickdraw does not let you control the baseAddr field, and I imagine that if I change it, I will be incompatible with graphics acceleration hardware that intercepts the offscreen pixmap calls. So, I am trying to roll my own offscreen pixmaps. I started with the code from the old FracApp, but it only does 8-bit pixmaps, where I need 32-bit pixmaps. So, I made changes as recommended, including such annoyances as creating an empty color table. Problem is, after some intensive debugging effort, peeking at all the fields of the CGrafPort, GDevice, and PixMapHandle with Lightsbug, and going over my code with a fine-toothed comb, I still crash during the initial EraseRect. Is there some magic wand I have to wave to get a 32-bit offscreen pixmap to work?