#1120821 `tiffset -u …` should reclaim space

Package:
libtiff-tools
Source:
libtiff-tools
Description:
TIFF manipulation and conversion tools
Submitter:
Al Ma
Date:
2025-11-16 22:01:03 UTC
Severity:
normal
#1120821#5
Date:
2025-11-16 21:58:12 UTC
From:
To:
Open up sh, and then:

$ wget -O example.tiff --quiet https://www.debian.org/logos/openlogo-75.png
$ convert openlogo-75.png example.tiff
$ ls -l example.tiff
-rw-r--r-- 1 username username 8798 16. Nov 22:44 example.tiff
$ tiffinfo example.tiff
=== TIFF directory 0 ===
TIFF Directory at offset 0x1afc (6908)
   Image Width: 75 Image Length: 92
   Resolution: 28.34, 28.34 pixels/cm
   Position: 0, 0
   Bits/Sample: 8
   Compression Scheme: None
   Photometric Interpretation: palette color (RGB from colormap)
   FillOrder: msb-to-lsb
   Orientation: row 0 top, col 0 lhs
   Samples/Pixel: 1
   Rows/Strip: 92
   Planar Configuration: single image plane
   Page Number: 0-1
   Color Map: (present)
   White Point: 0.3127-0.329
   PrimaryChromaticities: 0.640000,0.330000,0.300000,0.600000,0.150000,0.060000

$ for i in $(seq 1 100); do tiffset -d 0 -s 315 User example.tiff; tiffset -d 0 -u 315 example.tiff; done
$ ls -l example.tiff
-rw-r--r-- 1 username username 388598 16. Nov 22:46 example.tiff
$ tiffinfo example.tiff
=== TIFF directory 0 ===
TIFF Directory at offset 0x5e694 (386708)
   Image Width: 75 Image Length: 92
   Resolution: 28.34, 28.34 pixels/cm
   Position: 0, 0
   Bits/Sample: 8
   Compression Scheme: None
   Photometric Interpretation: palette color (RGB from colormap)
   FillOrder: msb-to-lsb
   Orientation: row 0 top, col 0 lhs
   Samples/Pixel: 1
   Rows/Strip: 92
   Planar Configuration: single image plane
   Page Number: 0-1
   Color Map: (present)
   White Point: 0.3127-0.329
   PrimaryChromaticities: 0.640000,0.330000,0.300000,0.600000,0.150000,0.060000

$


As you see, example.tiff grew despite adding and removing the same tag (here, 315 for Artist). The user-visible metadata remained the same. Apparently, `-u` doesn't reclaim space. From a user's viewpoint, this is simply wrong.  Please make `-u` actually cut out unused space.