[spuzvabob]

For a very similar use case I've developed custom text rendering in browser with support for CJK, Thai, Arabic (including bidirectional text with Arabic text within Latin or vice versa) and bitmap emojis.

Tbh all the complex part is handled by: https://github.com/harfbuzz/harfbuzzjs which handles the entire text shaping part (which glyphs to draw and the offset from previous glyph), then all that remains is text layout (linebreaking, kerning, line height, font size etc.) and the actual rendering ofc. Still took about 4 months of full-time work.

[rikroots]

I looked at harfbuzzjs at one point when the work was making me cry. It looks very useful, but in the end I decided against using it. Partly because I'm keen to keep my library free of direct dependencies. But also because I know both Chromium and Firefox use Harfbuzz internally (I wonder what Safari uses instead?) and it annoys me that even with access to that tool, browsers still manage to make a mess of the Canvas Text Metrics interface[1].

People who develop canvas libraries soon learn that they don't get to play with Nice Things like consistency across browser implementations for the standards they've (allegedly) agreed to respect.

[1] - https://developer.mozilla.org/en-US/docs/Web/API/TextMetrics