Comment by lewisjoe
14 hours ago
Quick overview of pretext: if you want to layout text on the web, you have to use canvas.measureText API and implement line-breaking / segmentation / RTL yourself.
Pretext makes this easier. Just pass the text and text properties (font, color, size, etc) into a pure JS API and it layouts the content into given viewport dimension.
Earlier you'll have to either use measureText or ship harbuzz to browser somehow. I guess pretext is not a technical breakthrough, just the right things assembled to make layouting as a pure JS API.
I have one question though: how is this different from Skia-wasm / Canvaskit? Skia already has sophisticated API to layout multiline text and it also is a pure algorithmic API.
> how is this different from Skia-wasm
It’s not wasm?
Skia brings in the world. You’re not wrong, and I understand the subtleties in the Q you asked (i.e. we’re talking Flutter; peer comment saying Skia-wasm is wasm comes across as pedantry to us because wasm vs JS is a compile-time option).
When we’re using flutter, we’re asking for there to be a device-agnostic render-the-world API, i.e. Skia / Impeller.
Here, someone took the time to code with AI a pure Typescript version of glyph rendering.
For us, the difference would sort of be like the difference between having ffmpeg in Dart, and abstractly, having an ffmpeg C library.
It’s been technically possible for years to have a WASM/FFI version with a Dart API, but it hasn’t happened because it’s a lot to take on yourself, and “real companies” would just use a server, because once you’re charging for it, people expect things like backup, download links, their computer not to need to be awake for minutes to complete a transcode, etc
Neatly completing the analogy: now, you or I takes on the grunt work of getting this hammered out and tested via AI over the next two weeks, and sticks it on GitHub. It’s not necessarily the language choice or tool itself that’s fascinating, but it legitimately breaks new ground in client-side media FOSS just to have it possible at all
If the author is right, this is going to be huge for GUI web frameworks and for future rich text editors.