Fonts not rendering under Linux

[fschutt]

Description

HarfBuzz currently returns spaces instead of glyph indices for any font if the application is running on Linux. This is probably not a problem of Azul, this should be reported to HarfBuzz developers.

Version / OS

• azul version: efaedc0

• Operating system: Ubuntu 17.04

• Windowing system (X11 or Wayland, Linux only): X11, Unity

Steps to Reproduce

Run the calculator example on Linux and see that the font on the buttons isn't loading

Additional Information

Note that the memory usage for any project that doesn't use fonts is very low (< 20MB versus a the "normal" 40MB). This is an indicator that WebRender uses a huge amount of memory for font rendering (often 10MB per font!). This should be reported and fixed in WebRender.

[tarriel]

I seem to be having the same problem, are there any work arounds?

[fschutt]

No, it's a problem with harfbuzz, has to be reported to the harfbuzz maintainers. Haven't found the time to do so yet.

[Stoeoef]

A call to hb_ot_font_set_funcs(new_hb_font) for a newly created harfbuzz font solves the issue.

Like this (See text_shaping.rs):

        let hb_font = unsafe { hb_font_create(hb_face) };
        unsafe { hb_ot_font_set_funcs(hb_font) };

This indicates that this method should be called by default, but well, I guess it isn't...
I hope that helps to narrow down the problem!