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TIFF and LibTiff Mail List Archive

Thread

2004.06.25 16:26 "[Tiff] Floating point tags and cross-platform", by Alan Torborg
2004.07.06 03:47 "Re: [Tiff] Floating point tags and cross-platform", by Andrey Kiselev

2004.07.06 03:47 "Re: [Tiff] Floating point tags and cross-platform", by Andrey Kiselev

I am trying to read tags of type double from tiff images that were created on a PC. I'm trying to read the tags with version 3.6.1 of LIBTiff on a Strong-Arm processor running Linux.

What I can recommend in first of all is to try the 3.7.0alpha (or, better, CVS version of libtiff). I'm very interested in testing before the new release.

Unfortunately - I am getting garbage from the tags. I'm assuming this is an issue with different floating point standards. Actually, the strong arm processor does not have a floating point processor - so we are using a floating point emulator (nwfpe) that, at this point, I know very little about. I do know that the emulator is supposed to be using IEEE floating point standard (similar to PC).

I'm probably know even less then you, but I can imagine that you need do the following:

  1. Undefine HAVE_IEEEFP macro in the config.h file (tiffconf.h for 3.6.1).
  2. Write floating point conversion routines, specific for your platform. You can find the samples of such routines in the tif_vms.c module. Such routine will be called every time libtiff will read a float value from file.

Andrey

Andrey V. Kiselev
Home phone: +7 812 5274898 ICQ# 26871517