Bug#1118385: texlive-binaries: corner-case PDF image nondeterminism

Hilmar Preusse <[email protected]> Tue, 19 May 2026 22:14:41 +0200

Newsgroups	gmane.linux.debian.devel.tetex
Message-ID	<agzEsT_2VgT-rsJp__2768.1828987383$1779221854$gmane$org@rasppi3>

Control: forwarded -1 https://github.com/pnggroup/libpng/discussions/864

On 19.10.25 Aaron M. Ucko ([email protected]) wrote:

> Package: texlive-binaries
> Version: 2025.20250727.75242+ds-4
> Severity: normal
> User: [email protected]
> Usertags: randomness toolchain
> 
Fix forwarded address.

> I have found that when a PNG image's row width does not correspond to a
> whole number of bytes, the low-order bits of the last byte in each
> uncompressed row can fluctuate between pdflatex runs, at least when
> libpng can perform SIMD-assisted decompression, yielding
> nondeterministic output even when arranging to supply predetermined
> timestamps.  (Moreover, this fluctuation can affect the length of the
> resulting compressed stream, slightly shifting the file position of
> subsequent content.)
>

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