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- Newsgroups: comp.sys.next.programmer
- Path: sparky!uunet!portal!cubism.portal.com!vlahos
- From: vlahos@cubism.portal.com (Harry Vlahos)
- Subject: Re: Device independent cached images? (12 bit and 16 bit grayscale images)
- Message-ID: <1992Nov4.091820.4269@cubism.portal.com>
- Sender: vlahos@cubism.portal.com (Harry Vlahos)
- Organization: -Independent NeXT Developer-
- References: <5711@rosie.NeXT.COM>
- Date: Wed, 4 Nov 1992 09:18:20 GMT
- Lines: 46
-
- In article <5711@rosie.NeXT.COM> aozer@next.com (Ali Ozer) writes:
- > In article <1992Oct27.212529.12565@ohsu.edu> filibert@ohsu.edu writes:
- > > ... So, I create another NXImage, lockFocus on it, and use some
- > >postscript magic to set the clipping path and copy from the original image
- into
- > >the new one. This new image is created with the initSize: method, and so I
- > >assume that it creates a NXCachedImageRep to hold the image. ...
- > >Finally, I need to get at the bitmap data in the etched image. One way to
- > >do this is to use the NXReadBitmap() function to read the image into a chunk
- of
- > >memory. ... when I do this on our NeXTDimension system, everything works
- fine.
- > >But, if I'm running the application on a monochrome slab, NXSizeBitmap() and
- > >NXReadBitmap() always treat the image as 2 bps, and 4 spp (RGBA)!
- >
- > Hmm. Do you set the depth limit of this second NXImage to 24 bits? If you
- don't,
- > then the NXImage you get is the same depth as the default depth of the
- system.
- > You should do:
- >
- > NXImage *myImage = [[NXImage alloc] initSize:...];
- > [myImage useCacheWithDepth:NX_TwentyFourBitRGBDepth];
- > if ([myImage lockFocus]) {
- > ... draw the image ...
- > ... now read it back ...
- > [myImage unlockFocus];
- > }
- >
- > Also please don't use the NXReadBitmap()/NXSizeBitmap() functions. Use the
- > NXBitmapImageRep method initData:fromRect:, which is a lot more efficient,
- > especially if you let the NXBitmapImageRep allocate and manage the data.
- > You can use the writeTIFF: method to save it out.
- >
- > Ali, Ali_Ozer@NeXT.com
- >
-
- I think I read somewhere in the 3.0 docs that the NXImage functions
- support 12-bit monochrome files now. I can't seem to locate it again.
- Is this true? How about 16-bit grayscale images.
- I have never written an NXCustomImageRep. Would that be a pretty
- easy task to undertake if the support for 12-bit or 16-bit is not there ?
-
-
- Harry, vlahos@cubism.portal.com
-
-