On Nov 13, 2011, at 11:11 , James Merkel wrote: > This is kind of interesting -- if I rotate the image in Preview (rather than > Image Capture), then the histogram looks normal. > Looking at the NSBitmapImageRep from Preview image, the order is RGBA and > there is no reported alpha channel. > Furthermore for the Preview rotated image, the Exif Orientation tag says > normal (horizontal), and the width and height are reported correctly. > For the Image Capture rotated image, the Exif Orientation tag says rotated 90 > degrees and the width and height are reversed (i.e. not reported correctly). > I think Preview is doing the right thing and Image Capture is doing the wrong > thing. > Why I get a bad histogram from the IMage Capture rotated image I'm not sure.
The implication of this is likely that you're misinterpreting the pixel format of the Image-Capture-rotated image. (For example, did it change the component values from 8-bit to 16-bit components or to floats, or something like that?). In principle, it shouldn't be too hard to resolve. Simply examining the data, or substituting a test image with known, predictably-arranged colors, should let you see why your histogram calculation doesn't match._______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
