Package: libtiff-tools
Version: 4.7.0-3+deb13u1
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.
