Tools for handling TTF and WOFF2
================================

https://fr.wikipedia.org/wiki/Web_Open_Font_Format_2


Print info about a TTF
----------------------

$ sudo apt-get install fontconfig
$ fc-query ./2017-11-13-OpenSans-Regular.ttf

  => The "lang" and the "capability" are interesting to know the
  supported language. "en" and "otlayout:latn" are a must.


Get version of a TTF
--------------------

$ fc-query -f '%{fontversion}\n' ./OpenSans/2017-11-13-OpenSans-Regular.ttf | \
  grep -v 'id' | perl -E 'printf "%.3f\n", <>/65536.0'

  => "1.100" indicates version "1.1"

Source: https://stackoverflow.com/a/43614521/881731


Conversion from TTF to WOFF2
----------------------------

$ sudo apt install woff2
$ woff2_compress 2017-11-13-OpenSans-Regular.ttf 

Source: https://dev.to/benjaminblack/converting-ttf-fonts-to-woff2-and-woff-3f5b



OpenSans
========

General information
-------------------

Official repository:
https://github.com/googlefonts/opensans/tree/master/

License:
Apache License 2.0

Google Fonts:
https://fonts.google.com/specimen/Open+Sans#license

Google CDN:
https://fonts.googleapis.com/css?family=Open+Sans

Debian package:

$ sudo apt-get install fonts-open-sans
$ ls -l /usr/share/fonts/truetype/open-sans/


Playing with the CDN
--------------------

To fetch the WOFF2 from CDN (selecting WOFF2 instead of TTF is done by
setting the HTTP Header User-Agent):

$ cd /tmp
$ curl -H 'User-Agent: AppleWebKit/537 Chrome/85' 'https://fonts.googleapis.com/css?family=Open+Sans'
  => The "latin" section is what we're looking for
$ wget https://fonts.gstatic.com/s/opensans/v18/mem8YaGs126MiZpBA-UFVZ0b.woff2


To fetch the TTF from CDN:

$ curl 'https://fonts.googleapis.com/css?family=Open+Sans'
$ wget https://fonts.gstatic.com/s/opensans/v18/mem8YaGs126MiZpBA-UFVZ0e.ttf
$ woff2_compress mem8YaGs126MiZpBA-UFVZ0e.ttf 
$ diff -s ./mem8YaGs126MiZpBA-UFVZ0e.woff2 ./mem8YaGs126MiZpBA-UFVZ0b.woff2

  => The files are identical


As of 2020-11-19, the version of the TTF is "1.101":

$ fc-query -f '%{fontversion}\n' ./mem8YaGs126MiZpBA-UFVZ0e.ttf | \
  grep -v 'id' | perl -E 'printf "%.3f\n", <>/65536.0'



Generation of the "./OpenSans" folder
-------------------------------------

$ mkdir ./OpenSans
$ cd ./OpenSans
$ REVISION=c0d8ce7dd46291a5d429ac537ddcd3617f4dc229
$ wget https://github.com/googlefonts/opensans/raw/master/LICENSE.txt
$ curl https://raw.githubusercontent.com/googlefonts/opensans/${REVISION}/ttfs/OpenSans-Regular.ttf > 2017-11-13-OpenSans-Regular.ttf
$ woff2_compress 2017-11-13-OpenSans-Regular.ttf

  => Note that the version of the TTF font is "2.010" (so more recent
  than the font on Google Fonts CDN)