[Dev] Packages with PDF files embedding non-free fonts

[Nelson H. F. Beebe]

List member grizzlyuser <grizzlyuser at protonmail.com> writes about the
question of PDF files in Parabola distributions that contain nonfree
fonts:

>> Does anybody have any thoughts on that? I wonder what are the best
>> next steps to do with this issue, if it's an issue indeed.

Font licenses vary by vendor.  

My recollection is that Adobe permits licensed fonts to be freely used
in PDF files posted to the Web, as long as the fonts are subsetted, so
that it is not possible to recover a complete working font from
decoding of the PDF file.

I also recall licenses from Bitstream and Mergenthaler/Linotype that
did not permit posting of PDFs.  

However, my reading of those licenses was several years ago, and
licenses may have since changed, especially in view of the wide, and
likely uncontrollable, font license violation on the Web of PDF files
that use system fonts.

What this boils down to probably is that we have to examine each PDF
file, extract a list of its fonts (e.g., Adobe Acrobat Reader can
display that list with the menu path

	File -> Document Properties -> Fonts

--- there ought to be a command-line tool to do that, but I don't
recall finding one), and then from the long font names, like
"Arial-BoldItalicMT", attempt to figure out the vendor, and track down
the applicable license.

Noted font designer Chuck Bigelow wrote in 1986 about font licensing
issues:

	Notes on typeface protection
	TUGboat 7(3) 146--151 October 1986
	https://tug.org/TUGboat/tb07-3/tb16bigelow.pdf

Incidentally, Chuck is hosting the TeX User Group 2020 conference next
summer at the University of Rochester in NY State.  The date has not
yet been set, but TUG's annual meetings are traditionally in late July
or early August when they are held in the northern hemisphere.

Documents that are typeset with TeX (pdftex, pdflatex, luatex, xetex,
...)  using fonts from the TeX Live distributions do not have license
problems, but those programs permit users to employ system fonts as
well, and those in turn may have restricted licenses.

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