Bug#796490: [texlive-latex-base] pdflatex does not create reproducible pdfs with multiple images

[Norbert Preining <preining@logic.at>]

Hi David,

> The function write_png_rgb_alpha allocates twice as much memory as is
> necessary for the smask buffer. The second half of the buffer is left
> uninitialized and the whole buffer is copied to the output PDF file. It
> only arises with PNG images that have an alpha channel. (I suppose
> optipng removes the alpha channel when possible, which is why it made
> the problem go away.)
> 
> I think the bug is in texk/web2c/pdftexdir/writepng.c, where a "/ 2"
> should be "/ 4"; i.e., 1 in 4 bytes is an alpha byte:

Do you think that an update for testing (in pre-release freeze) is
required? Or possible?

Norbert

--
PREINING Norbert                               http://www.preining.info
Accelia Inc.     +    JAIST     +    TeX Live     +    Debian Developer
GPG: 0x860CDC13   fp: F7D8 A928 26E3 16A1 9FA0 ACF0 6CAC A448 860C DC13