CJK glyphs rendering as "glyph not found" ("tofu") characters

[ssokolow]

The Bustle Flatpak appears to not have its fonts configured properly for displaying CJK characters because they render as "tofu" characters. (i.e. Windows-style empty rectangle renderings of the .notdef glyph)

For example, try copy-pasting 文字化け into the Address field in the Record Address dialog as a minimal-effort test.

I can see this being a big problem for viewing the contents of D-Bus messages on systems not configured for a latin script. (eg. For diagnosing encoding mismatches between two programs, where you need to figure out whether it went wrong on the sending or receiving side.)

If it helps you narrow down the problem, the AntiMicroX, Arduino IDE, Blender, Firefox, FocusWriter, Godot, JDownloader, KCachegrind, Krita, LMMS, MEGAsync, Okteta, Sweet Home 3D, Thunderbird, Tor Browser, and Ungoogled Chromium flatpaks work fine on this issue... though Deluge, Flatseal, HandBrake, Inkscape, and jstest-gtk do have the same problem as of my opening this bug. (I've reported bugs for some of them, but not all... since cases like jstest-gtk were a struggle just to find a text-entry field to test with.)

[wjt]

Works fine on my machine.

Please try running Bustle from a Terminal window. Do you see any suspicious warnings?

flatpak run org.freedesktop.Bustle

You can also check:

flatpak info org.freedesktop.Platform.Locale/x86_64/20.08

Which Subdirectories are shown as installed?

[ssokolow]

Please try running Bustle from a Terminal window. Do you see any suspicious warnings?

Yes, actually. These appear when I hit Ctrl+v to paste the test string.

(bustle:2): Pango-WARNING **: 06:20:58.331: failed to create cairo scaled font, expect ugly output. the offending font is 'VL Gothic 9.9990234375'

(bustle:2): Pango-WARNING **: 06:20:58.332: font_face status is: file not found

(bustle:2): Pango-WARNING **: 06:20:58.332: scaled_font status is: file not found

(bustle:2): Pango-WARNING **: 06:20:58.349: failed to create cairo scaled font, expect ugly output. the offending font is 'VL Gothic 9.9990234375'

(bustle:2): Pango-WARNING **: 06:20:58.349: font_face status is: file not found

(bustle:2): Pango-WARNING **: 06:20:58.349: scaled_font status is: file not found

flatpak info org.freedesktop.Platform.Locale/x86_64/20.08

Subdirectories: /en

However, other applications which also report using org.freedesktop.Platform version 20.08 like com.sweethome3d.Sweethome3d don't exhibit this problem, so I'm guessing it's probably not the Locale support in the platform itself.

Those Pango errors do look promising, though, because I've noticed that all the applications that are exhibiting the problem are GTK-based and all the applications which aren't exhibiting the problem are either not using GTK or are things like Firefox and Ungoogled Chromium which carry along their own implementations of 99% of what GTK provides and just use it for system integration.

[ssokolow]

Aha! sudo apt-get remove fonts-vlgothic makes it work!

Could you check whether installing the VL Gothic font breaks it on your system?

[wjt]

What is the output of locale?

[ssokolow]

LANG=en_CA.utf8
LANGUAGE=en_CA:en
LC_CTYPE="en_CA.utf8"
LC_NUMERIC="en_CA.utf8"
LC_TIME="en_CA.utf8"
LC_COLLATE="en_CA.utf8"
LC_MONETARY="en_CA.utf8"
LC_MESSAGES="en_CA.utf8"
LC_PAPER="en_CA.utf8"
LC_NAME="en_CA.utf8"
LC_ADDRESS="en_CA.utf8"
LC_TELEPHONE="en_CA.utf8"
LC_MEASUREMENT="en_CA.utf8"
LC_IDENTIFICATION="en_CA.utf8"
LC_ALL=en_CA.utf8

[wjt]

Simply installing fonts-vlgothic had no effect.

Since this affects other apps besides Bustle on your system I'm going to close this ticket. I think https://github.com/flatpak/flatpak/issues/4641 is sufficient to track the issue.

[ssokolow]

Yeah. I created that one later, after realizing what was common between the handful of apps which had CJK issues. It makes sense to close this one.