We use text shadows to create "outlines" around text shapes. These
shadows are rendered on the GPU. In Chrome (and on computers with a
capable GPU) text shadows work pretty well, however on Safari—and in
particular on iOS—they cause massive frame drops.
https://github.com/tldraw/tldraw/assets/23072548/b65cbcaa-6cc3-46f3-b54d-1f9cc07fc499
This PR:
- adds an LOD to text shadows, removing them at < 35% zoom
- removes text shadows entirely on Safari
If we had a "high performance" or "low-end device" mode, then shadows /
text shadows would be the first to go.
### Change Type
- [x] `sdk` — Changes the tldraw SDK
- [x] `improvement` — Improving existing features
### Test Plan
1. Use text shapes on iOS.
2. Use text shapes on Safari.
3. Use text shapes on Chrome.
### Release Notes
- Improves performance of text shapes on iOS / Safari.
2bbab1a790