pdftex bug

[Ulrike Fischer]

Am Wed, 13 Sep 2023 11:00:43 +0200 schrieb Martin Münch:

> Hi!
> 
> cfftot1 changed its output "to work around pdftex bug":
> 
> https://github.com/kohler/lcdf-typetools/commit/606aa7236133a97c295f80bfd29a33ca022ddc05
> 
>  > Fix output of cfftot1 to work around pdftex bug.
>  >
>  > The default precision of real-number output, %.12g, could lead
>  > to very long FontMatrix output lines. For one font (mentioned in
>  > issue #34), you would see:
>  >
>  > /FontMatrix [0.000833333333333 0 0 0.000833333333333 0 0] readonly def
>  >
>  > This apparently overflows some code path in pdflatex, because the
>  > output PDF file does not render the font. This commit instead uses
>  > 9 decimal digits of precision, which leads to
>  >
>  > /FontMatrix [0.000833333333 0 0 0.000833333333 0 0] readonly def
>  >
>  > and a correctly rendered PDF after pdftex inclusion and processing.
>  >
>  > Simultaneously, do not output defaulted keys (like BlueShift 7),
>  > and always output BlueValues (it is required).
> 
> Would it be possible to change pdflatex to handle more than 9 digits? 
> cfftot1 might not be the only way to create them.

Well I wouldn't count it a pdftex bug if adobe reader can't handle 

/FontMatrix [0.000833333333333 0 0 0.000833333333333 0 0]

but works fine with 

/FontMatrix [0.000833333333 0 0 0.000833333333 0 0]


I can confirm that shortening the numbers in the PDF resolves the
problem with the simpleicon fonts (I looked at the problem
https://tex.stackexchange.com/questions/689446/ a few weeks ago and
still had a test file around) 

But I don't think that pdftex (and the other engine) can do much
here. Imho they simply copy the values from the .pfb. You could try
to make a bug report to adobe, but beside the fix in cfftot1 is imho
the best one can do.


-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/