Decide on terminology for map loading states

[lucaswoj]

In mapbox/mapbox-gl-native#3318 and mapbox/mapbox-gl-js#1715 we're trying to come up with the right terminology to describe map loading states. So far, we have identified at least 2 states that need unique descriptive names (but I think there are some more interesting ones)

• everything has loaded for the initial map viewport (presently captured by the load event)
• everything has loaded for the current map viewport (presently unnamed)

(NOTE: "everything" = styles, tilejson, tiles, geojson, glyphs, sprites)

[brunoabinader]

I vote for ready instead of loaded because loading a resource does not necessarily indicate that a resource is ready for usage e.g. we can say that a style is ready after all its sources in which at least one visible layer are loaded, which means not all of its sources needs to be loaded.

[jfirebaugh]

• everything has loaded for the initial map viewport (presently captured by the load event)

Let's leave this event named load, for backward compatibility and window.onload precedent.

• everything has loaded for the current map viewport

I vote for naming the event quiesce, and the accessor isQuiescent(). It's an uncommon enough word that we can attach our own domain-specific meaning to it.

qui·es·cent

adjective: in a state or period of inactivity.
"After an animation finishes and all tiles have been loaded, the map becomes quiescent and the frame rate drops to zero."

[tmcw]

-1 for quiesce, on account of spelling difficulty

[lucaswoj]

+1 for quiesce, on account of semantic differentiation from load and it being and uncommon enough word that we can attach our own domain-specific meaning to it.