Wrong PDF standard fonts are replaced when fonts package "fonts-texgyre" is installed - PDFs are rendered with missing characters

[Tom Fields]

Hi,

please see following bug report on freedesktop with screenshots:
https://bugs.freedesktop.org/show_bug.cgi?id=79527

When fonts package "fonts-texgyre" from the "texgyre" package is installed,
all PDFs containing e.g. a reference to a "Helvetica" font, which is usually not installed on Ubuntu systems, fontconfig mages a very bad choice with one of the fonts supplied in fonts-texgyre (like "TeX Gyre Heros").

The problem is, apparantly the texgyre fonts us a different naming style for some important glyphs (like greek characters contained in many mathematical documents), so that fontconfig cannot find them.

See screenshots in abovementioned bugreport:
==> PDF readers only display a blank space in this case, which has potentially disastrous results (there are six orders of magnitude difference between an Ampere current and a Microampere current e.g..).

There is a likely explanation also unter this bugreport:
https://bugs.launchpad.net/ubuntu/+source/tex-gyre/+bug/1317599

==> Please change the Ubuntu font configuration so that all those PDFs are displayed correctly.

[Tom Fields (udzelem)]

Who experiences this problem can use the following workaround as described in the source bugreport:
Add to ~/.config/fonts.conf the following section before the "</fontconfig>" tag:

<match target="pattern">
 <test name="family">
  <string>Helvetica</string>
 </test>
 <edit name="family" mode="prepend" binding="same">
  <string>NimbusSansL</string>
 </edit>
</match>

A real fix for the original problem however is likely a change of the Ubuntu trusty default fontconfig config (package: fontconfig-config) or an update to the font renderer. (Quoting https://bugs.launchpad.net/ubuntu/+source/tex-gyre/+bug/1317599/comments/8:
"Ideally, renderers would notice that the glyph name they want is unavailable and look for alternate names.")

[madbiologist (me-again)]

This is fixed on Utopic in fontconfig 2.11.1-0ubuntu3 and on Trusty in fontconfig 2.11.0-0ubuntu4.1

the Trusty changelog says:

  * 0001-Bug-73291-poppler-does-not-show-fl-ligature.patch: Don't alias TeX
    Gyre Termes to Times as it has a broken 'fi' ligature. (LP: #1325230)
 -- Iain Lane <email address hidden>

Apparently people who upgrade from Trusty to Utopic are still affected by this bug.

An even better fix is in poppler 0.28.1-1ubuntu1, which is currently available in Ubuntu 15.04 "Vivid Vervet" development version. As a result of this fix, there are comments in an upstream bug for the fontconfig changes to be reverted so as to restore normal behaviour to LaTex and other packages that use the texgyre fonts.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Antonis Pappas (bigfatpugsley)]

This still isnt fixed in trusty. It is especially annoying since it messes up ALL sans-serif greek websites in firefox, while google-chrome having its own font configuration is totally unaffected.

[Antonis Pappas (bigfatpugsley)]

The problem is better illustrated here.