appstream-builder fails to parse Noto Nastaliq Urdu font

[tagoh]

The log file says that:

DEBUG:   Getting filename match for google-noto-nastaliq-urdu-fonts-20250201-1.fc43.noarch.rpm
DEBUG:   Exploding tree for google-noto-nastaliq-urdu-fonts
DEBUG:   Adding extra package google-noto-fonts-common for google-noto-nastaliq-urdu-fonts
DEBUG:   Processing google-noto-nastaliq-urdu-fonts-20250201-1.fc43.noarch.rpm with appdata
DEBUG:   Running asb_plugin_process() from appdata
INFO:    Upstream contact <fonts@lists.fedoraproject.org>
DEBUG:   Running asb_plugin_process_app() from desktop
DEBUG:   Running asb_plugin_process_app() from font
WARNING: Failed to get font from /tmp/appstream/google-noto-nastaliq-urdu-fonts-20250201-1.fc43/usr/share/fonts/googl
e-noto/NotoNastaliqUrdu-Bold.ttf: Could not generate 64x64 font icon with 'أب'
WARNING: Failed to get font from /tmp/appstream/google-noto-nastaliq-urdu-fonts-20250201-1.fc43/usr/share/fonts/googl
e-noto/NotoNastaliqUrdu-Regular.ttf: Font screenshot already exists with hash 876c6d036d8de8ae448c2218fa1cd888

However both NotoNastaliqUrdu-Bold.ttf and NotonastaliqUrdu-Regular.ttf has U+0623 and U+0628.

$ hb-view --text "أب" /usr/share/fonts/google-noto/NotoNastaliqUrdu-Regular.ttf

[hughsie]

Could you debug a bit why the Could not generate 64x64 font icon error is being generated?

[tagoh]

This may happens because the Arabic/Urdu text is RTL direction and cairo doesn't support RTL text. You need to use Cairo integration in Harfbuzz and FriBiDi to get the direction of the text.

[hughsie]

You need to use Cairo integration in Harfbuzz and FriBiDi

Patches very welcome for that; I have no idea how that would work.

[tagoh]

Any chance to review PR?