PDF doesn't render Chinese text correctly

[JasonHK]

The font currently used doesn't have the glyphs needed to render Chinese (as well as Japanese, Korean and other languages in the future). Maybe should introduce a fallback font or use a one for all font (e.g. Unifont) instead.

P.S. I forgot to raise the issue before

[eljojo]

Hey @JasonHK , thanks for opening this issue! wow huge oversight, I didn't realize.

Yes, it would be good to do something about this, I wonder what the right option here should be. Some things I'm weighing:

• I'd like the app to support other languages ( مطلوب مترجمون — 翻訳者募集 — अनुवादक चाहिए — Looking for translators! #93 ), I wonder if there's one font that "works for all" or we need to have one font per language
• I don't want to degrade the experience for other languages, I'm thinking it might be good to make these new fonts "kick in" only when necessary

what do you think?

[JasonHK]

There are 2 FOSS fonts that came to my mind:

GNU Unifont will work for all languages out-of-the-box but it's pixelated and not pretty.

Noto Sans and Noto Sans Mono are better looking but I'm not sure the base font (without the regional variants) will work for every languages (probably should but need verification)

[eljojo]

which one would you prefer for Chinese? I'm thinking, the app can have a map of language -> font, as an override when needed for languages like Chinese, that way the others stay unaffected.

If you want to open up a PR I'd be happy to review :)