On 2026/05/13 8:49, John Collins wrote:
2. I don't think this has anything to do with libpng, since I was able to reproduce the same problem on a trivial file,
hello.tex, without included graphics:
\documentclass{article}
\begin{document}
Hello
\end{document}
I used the following script to test whether the pdf file changes on successive
compilations:
for i in 1 2; do
pdflatex -interaction=batchmode
"\pdfinfo{/CreationDate(D:20260429034606Z)/ModDate(D:20260429034606Z)}\input{hello.tex}"
mv hello.pdf hello${i}.pdf
sleep 1
done
diff -sca hello1.pdf hello2.pdf
With
export SOURCE_DATE_EPOCH=`perl -e "print time();"`
export FORCE_SOURCE_DATE=1
for i in 1 2; do
pdflatex -interaction=batchmode
"\pdfinfo{/CreationDate(D:20260429034606Z)/ModDate(D:20260429034606Z)}\input{hello.tex}"
mv hello.pdf hello${i}.pdf
sleep 2
done
I obtain the same hello1.pdf and hello2.pdf:
cmp hello1.pdf hello2.pdf
echo $?
0
On the other hand, with
export SOURCE_DATE_EPOCH=`perl -e "print time();"`
export FORCE_SOURCE_DATE=1
for i in 1 2; do
pdflatex -interaction=batchmode
"\pdfinfo{/CreationDate(D:20260429034606Z)/ModDate(D:20260429034606Z)}\input{valuators.tex}"
mv valuators.pdf valuators${i}.pdf
sleep 2
done
%valuators.tex
\documentclass{article}
\usepackage{graphicx}
\begin{document}
Hello.
\includegraphics[width=8cm]{valuators.png}
\end{document}
where valuators.png is obtained from
https://salsa.debian.org/fltk-team/fltk1.4/-/blob/main/documentation/src/valuators.png?ref_type=heads
I obtain different valuators1.pdf and valuators2.pdf:
cmp valuators1.pdf valuators2.pdf
valuators1.pdf valuators2.pdf differ: char 421, line 26
Thanks,
Akira
