Font blurring doesn't work on Firefox

[acwooding]

This is reproducible on Firefox with multiple examples (not just cord19). It works fine in tests on chromium and seems to be fine in Safari as well.

Note: I'll add more browsers to the UI tests so we can catch stuff like this.

[lmcinnes]

I working on fixes for this right now, so hopefully I'll have soemthing soon.

[lmcinnes]

I'm having some issues managing to remedy this properly. Essentially the problem is that deck.gl is not loading the font for the TextLayers (at least some of them). I've tried to enforce font loading in javascript prior to creating the text layers but that seems to have limited success. A refresh of the page/plot generally also solves the issue, but is less than desirable.

The only alternative I see right now is backing out the variable weight fonts for labels which is, unfortunately an otherwise quite useful feature. Suggestions are welcome.

[lmcinnes]

I have an issue in visgl/deck.gl#9479 that may help clarify some of the issues here.

[lmcinnes]

This looks like it is going to be hard to fix without something upstream in deck.gl, so I'm going to roll back the PR that added the variable weight fonts.