Implementing in WebAssembly

[ThatGuySam]

This may be a dumb and obvious question but how would you implement this in WebAssembly so you can use it with things like Node Serverless Functions and Edge Workers?

[gkrasin]

The simplest way would be to use Emscripten for that: https://emscripten.org/ It can compile C and C++ into WebAssembly. Given that qoi is a simple header-only library, this should be almost as easy as running a hello world for Emscripten.

It helps that no machine assembly / SIMD instructions are used in qoi, which is usually the primary pain when compiling into WebAssembly.

[ThatGuySam]

I would assume I would have to pass in the whole image file into the "wasmed" qoi script as opposed to streaming the file.

Again, forgive my ignorance if these are simple questions.

[gkrasin]

That sounds right. I recommend following this guide: https://developer.mozilla.org/en-US/docs/WebAssembly/existing_C_to_wasm

It shows how to compile libwebp into WebAssembly and get it working in the browser, so it should be very similar in the qoi case, just simpler.

[lifeart]

following this totorial https://emscripten.org/docs/getting_started/Tutorial.html

I got:

error (looks like i neeed to read readme carefully)

Anyway, as mentioned fs related logic shold be different for wasm, it could be array of pixels as input + dimensions

[Robaire]

Rust supports compiling directly to WebAssembly. It should be fairly straight forward to take the Rust clone and create a JavaScript wrapper as an alternative solution.

[ikskuh]

This is also on my bucket list. If i find the time today or tomorrow, i can try creating a "wasm polyfill" for QOI support based on the Zig impl

[farteryhr]

i think this is suitable as an exercise for the readers to handwrite wasm.