Any advice / learnings on using canvas from wasm for this kind of GUI stuff? If I get it right, you just implemented the editor yourself, not using any sort of widget system.

People often recommend not trying to implement editors on top of canvas because of ... reasons [1] [2], but it seems your implementation ended up being pretty simple? (at least in terms of lines of code...).

1: https://www.w3.org/TR/2dcontext/#best-practices

2: https://stackoverflow.com/questions/12425111/creating-canvas...