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February 2009
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2009.02.13 17:36 "Re: TIFFReadRGBAImage w/ 8bit-gray + aplha", by Bob Friesenhahn
On Fri, 13 Feb 2009, Joris Van Damme (AWare Systems) wrote: > I've tested with current beta of LibTiff 4. Low-level LibTiff > (TIFFReadEncodedXxx) does not get into trouble. However, the LibTiff RGBA > interface does crash and burn, access violation style, even in version 4.0. > At first examination, there's nothing that much out of the ordinary to this > image, except that the two channels (MinIsBlack grayscale channel and the > pre-calculated alpha channel) are stored planar, not chunky (in LibTiff > speak, the tag TIFFTAG_PLANARCONFIG has the value PLANARCONFIG_SEPARATE) > which is not all that common but certainly is perfectly legit. The crash is likely due to an error in error handling. Via GraphicsMagick, libtiff returns this error: "Compression algorithm does not support random access." I see such errors whenever libtiff tries to read a floating point TIFF (written by Photoshop CS2) which uses LZW compression. However, this file is not floating point. This suggests a problem with reading LZW compressed files written by recent Photoshop. Bob ====================================== Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/