Re: [GM-bugs] Re: tiff with jpeg compression

[Bob F. <bfr...@si...>]

On Fri, 9 Sep 2005, Michal Kowalczuk wrote:

> On 2004-03-26, Bob Friesenhahn <bfr...@si...> wrote:
>
>>> at first - thanks for your reply. i didn't know, that graphicsmagick
>>> realy crashs with this pic, i also got a exception. (i forgot to say
>>> that i'm using gm-1.0.4 and work with a pentium 4 - 2,5ghz and winxp)
>
> I don't know if my problem is related to this thread, but it looks similar.
> My configuration is: SPARC64, Solaris 10, gm-1.1.6, libtiff-3.7.3.
> I found that gm crashes on:
> #v+
> if (TIFFGetField(tiff,TIFFTAG_DATETIME,&text) == 1)
> #v-
> (coders/tiff.c, line 748)
>
> libtiff treats it as a "Custom value", tag code == 36867 and returns two
> values via va_arg (count and value), while gm expects one value (only value,
> no count).

The libtiff documentation says that just one argument is returned. 
Also, I see that libtiff's own utilities are implemented as if only 
one argument is returned for TIFFTAG_DATETIME.

I do see this in a changelog dated 2005-06-01:

         * libtiff/{tif_dirinfo.c, tif_dir.h, tif_dir.c, tif_print.c}: Make
         DocumentName, Artist, HostComputer, ImageDescription, Make, Model,
         Copyright, DateTime, PageName, TextureFormat, TextureWrapModes and
         TargetPrinter tags custom.

Maybe this represents an API change. I have posted to the tiff mailing 
list to see what opinions emerge.  I do know that recent libtiff 
enforces a 20 character length limit for DateTime.

> Strange is that I've observed this bug on:
> * SPARC64, Solaris 10 (always)
> * then on x86, Solaris 10 (only once, after "make clean; make" of my
>  application it never crashed again),
> * never on x86, Linux (am I lucky? ;])

It is not uncommon for there to be bugs in libtiff in the tiff 
directory support.  It seems that bugs are fixed in this area pretty 
often.  Presumably fixed bugs mean that the code is getting better.

If you can send me a sample image which causes the problem, then I 
will try to reproduce the problem using the latest libtiff development 
code.

Note that Solaris includes its own anchient copy of libtiff.  Make 
sure that your build does not accidentally use it.  See PLATFORMS.txt 
for some notes regarding Solaris's libtiff and how to not be bit by 
it.

Bob
======================================
Bob Friesenhahn
bfr...@si..., http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/