Am 04.06.26 um 18:24 schrieb Norbert Preining:
On Thu, 04 Jun 2026, Md Ayquassar wrote:
For an unadvertised reason,
/usr/share/doc/texlive-doc/latex/webquiz/examples/*.png and
/usr/share/doc/texlive-doc/latex/beautybook/inner_pics/titleimages/songeven.png
have caNv chunks. This chunk is not standard and creates issues down certain
tool chains; cf. http://bugs.debian.org/1115346. The documentations opened by
`texdoc webquiz` and `texdoc beautybook` keep silent about this tag. If this
tag is really necessary, document why; otherwise, remove it from the offending
PNG files (`pngcrush -brute -ow -rem caNv file.png`).
Sorry, why?
Sorry, wrong question. The right question is: “Why shipping nonstandard stuff
in the first place”? On my installation, only the TeX-Live documentation has
this issue, whereas all PNG files in all the other packages on my system are
fine with regard to the absence of caNv.
an up-upstream bug, not TeX Live, but
upupstream webquiz and beautybook authors, so should be reported there
and not here.
I appreciate your work, and I'm surprised that you question the standard
procedure, which is to report a bug to the operating-system maintainers first.
You may check whether the issue is present in the development version of the
packages and, if it is present, report upstream (or ask someone else, including
me, to do this), but you shouldn't complain about a user filing a bug against a
Debian package in the first place.
This are file in the documentation hierarchy in TeX Live.
Why is any tool at all using these files at all?
As examples. In general, you don't know how the images are going to be used in
the end. http://bugs.debian.org/1115346 documents what goes wrong silently in a
particular conversion (it gets worse if there are more conversions, as caNv is
reported by `pngcheck -v` as safe to copy), and a user may notice the error
years after having shipped a wrong output.
