Really cool to see JSON Canvas getting attention. (Hi, kepano!) It was one of the inspirations for OCIF (Open Canvas Interchange Format), which we've been working on since JSON Canvas came out.

JSON Canvas nails the simplicity-it's easy to read and easy to implement. We wanted to build on that spirit while tackling some of the challenges showing up in this thread: nested canvases, extensibility for custom app data, text styling, coordinate systems, and round-tripping between different canvas apps without data loss.

OCIF v0.7.0 just came out. It's designed to be an interchange format — so different canvas tools (Excalidraw, TLDraw, Obsidian, etc.) can export/import each other's canvases.

Some highlights:

- Extensible: apps can attach their own data via extensions, so nothing gets lost even if the features aren't supported

- Nested canvases via parent-child node relationships

- Local coordinate systems (addresses the pixel positioning concerns raised in another comment here)

- Text styling, viewport control, and more via built-in extensions

If JSON Canvas isn't quite meeting your needs, OCIF[1] might be worth a look.

https://canvasprotocol.org