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Is there a simple method for checking if an NSImage Object contains a grayscale image?

What I am trying to do is count the number of colour and black and white pages within a pdf. As far as I can tell the only real solution to this is to render the pdf pages as images and then work from there. I didn't want to have to check every pixel if possible but so far that's all I can come up with.

Matthias Bauch
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Chris Hattrell
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1 Answers1

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You can access the NSImage's -representations (which returns an array of NSImageRep instances) and query the returned NSImageReps for these details.

Primary NSImageRep and CGImage details of interest include:

  • assigned colorspace
  • the number of components from the image's bitmap info, bits per component, and bits per pixel.
justin
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  • Thanks for the quick reply, I've had a look at what you have suggested but all return the same value (when the images are created from the same pdf) regardless of the colours present. I may be missing something, it happens a lot. – Chris Hattrell Dec 23 '11 at 18:46