Need to detect when GL is finished painting after addLayer() is called

[peckjon]

#826 provides a way to detect when a map first finishes loading.

However, there can also be a significant gap between when map.addLayer() is called and when all shapes in that layer are fully rendered, especially for complex/dense shapes.

Can an event or callback be added to detect this?

[peckjon]

Incidentally, I thought I could get at this by waiting for the GL context to finish rendering, but (map.getCanvas().getContext('webgl') || map.getCanvas().getContext('experimental-webgl')).finish(); does not appear to block until the paint is complete.

[jfirebaugh]

Yes, we're tracking this in #1715, with additional discussion in #1904.