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June 2010
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2010.06.11 23:26 "Re: Class Y images with alpha channels", by Bob Friesenhahn
On Fri, 11 Jun 2010, Thomas Richter wrote: > Hi folks, > > is there a possibility to add an alpha channel to a class Y (YCbCr) tiff > image? I don't see this in the rev.6 specs. You could add an alpha channel as an extra sample or a fourth plane in a planar TIFF, but since the specification does not mention doing this, perhaps only your own application could make sense of it. I think that using planar TIFF is safest since readers can skip reading the last plane and still return the YCbCr image, but not many readers support planar (separated) TIFF. Bob -- Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/