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August 1999

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1999.08.14 13:11 "Problem in compression LZW : produce a .TIF that crash Paint Shop Pro 5", by Gilles Vollant
1999.08.14 13:45 "Re: Problem in compression LZW : produce a .TIF that crash Paint Shop Pro 5", by Helge Blischke
1999.08.14 14:00 "Re: Problem in compression LZW : produce a .TIF that crash Paint Shop Pro 5", by Gilles Vollant
1999.08.14 14:40 "Re: Problem in compression LZW : produce a .TIF that crash Paint Shop Pro 5", by Helge Blischke
1999.08.14 14:44 "Re: Problem in compression LZW : produce a .TIF that crash Paint Shop Pro 5", by Helge Blischke

1999.08.14 14:40 "Re: Problem in compression LZW : produce a .TIF that crash Paint Shop Pro 5", by Helge Blischke

Gilles Vollant wrote:
> 
> OK, I resend the file. How do you check it ?
> 
> -----Message d'origine-----
> De : bla@srz-berlin.de [mailto:bla@srz-berlin.de]De la part de Helge
> Blischke
> Envoye : samedi 14 aout 1999 15:46
> A : Gilles Vollant
> Cc : tiff@olympiakos.com
> Objet : Re: Problem in compression LZW : produce a .TIF that crash Paint
> Shop Pro 5
> 
> Gilles Vollant wrote:
> >
> > I've written with VC++ an apps which convert .BMP to .TIF, allow selecting
> > the TIFF compression.
> >
> > This apps run well, but I've one image, 1006x764x256 colours which
> generate
> > a buggy TIF : If I open the Tiff with Paint Shop Pro 5, Paint Shop Pro
> > crash.
> >
> > The Tiff is saved in LZW without predictor. If I save uncompressed TIF,
> PSP
> > open it.
> >
> > I've the problem with both 3.4beta 37 and 3.5.1 LibTiff.
> >
> > I can send the image and the apps to anyone which is interrested.

I looked at the image and found the following:

1) it is LZW compressed, and the predictor value is 2, what means
   horizontal differencing - as opposed to what you stated above.
2) The resolution unit is specified, but neither X nor Y resolution is
given.
   Many apps default the resolution to 72 dpi if not or not sufficiently
specified,
   but it may be your app(s) barf on it.
3) The image is divided in many many tiny strips. It might be the
application
   cannot cope with strips or tiles.

Apart from these comments, the TIFF file conformes to the spec and is
perfectly decodable.
Try to make a copy using tiffcp (one of the utilities that come with
libtiff):
tiffcp -c lzw -r number old.tif new.tif
where number is at least the image length (in pixels). This will make a
copy
with predictor value 1 (no differencing) and make the image consist of
only one large
strip, and let us know if it wors then.

He|ge

-- 
H.Blischke@srz-berlin.de
H.Blischke@srz-berlin.com
H.Blischke@acm.org