Update coordinates of image/video sources

[averas]

This fixes #1880 by adding support for updating the coordinates on image- and video sources.

While doing this I noticed this part which I don't really understand how it's supposed to work:

    onAdd: function(map) {
        this.map = map;
        if (this.image) {
            this.setCoordinates();
        }
    }

Won't a call without arguments to setCoordinates (perviously createTile) cause an error on the subsequent coordinates.map() in that function?

[lucaswoj]

This method gets fired when the ImageSource is added to an instance of Map. There are two cases to consider:

• the HTTP request for the image finishes before the ImageSource gets added to the map
• the HTTP request for the image returns after the ImageSource gets added to the map

The code in this method deals with the first case.

I think the lack of an argument to setCoordinates is a mistake. The line should be

this.setCoordinates(this.coordinates)

[averas]

Oh, I am completely with you on why the code exists, it was the intentional or unintentional lack of arguments that got me confused. If it in fact was unintentional everything makes total sense.

[lucaswoj]

Thank you for the PR @averas! Looking forward to the next round of revisions, feedback from some other Mapbox-ers, and then shipping this!

[ansis]

Looks good to me!

Is there a better name than coordinates to use here? I realize the choice to use coordinates happened before this pull request but if we want to rename it now would be a good time.

corners, geometry?

[lucaswoj]

I like coordinates.

Any last words before we 🚢 @jfirebaugh @mourner?

[mourner]

[jfirebaugh]

👍

[lucaswoj]

Merged in e7b551c 🚀

Thanks @averas!