iOS tile source bridge API

[incanus]

Easy to way to use old RMTileSource protocol on iOS.

[fotiDim]

Definitely need that

[incanus]

Related to this, with the recent addition of -[MGLMapView setMapID:], folks will probably expect SDK-style raster layers to work easily.

[incanus]

We are splitting the GL ID's into mapID and styleID. Raster-based sources aren't a priority for b2, but in b3 and later we will be picking this back up.

[incanus]

The main problem here is that the styleID API expects an HTTP or local style URL. While we could generate a style, we can't actually easily host it in a place that GL could consume as a vector style.

Other ideas:

• Auto-parse return of mapbox:// URLs and if TileJSON for rasters, just auto-build a style which shows them. Related: Improve style 404 error #1841
• Add a new protocol (e.g. mapbox-raster://) for this.
• Create a command line tool that helps generate the JSON style around a single raster source for inclusion in an app.

[incanus]

As an example, this is all that's required to use a legacy raster map ID in GL:

{
  "version": 7,
  "name": "Raster",
  "sources": {
    "raster": {
      "type": "raster",
      "url": "mapbox://examples.map-pgygbwdm",
      "tileSize": 256
    }
  },
  "layers": [{
    "id": "raster",
    "type": "raster",
    "source": "raster",
    "paint": {
      "raster-fade-duration": 100
    }
  }]
}

[incanus]

Use like so:

[self.mapView setRasterMapID:@"examples.map-pgygbwdm"];

[incanus]

👉 #1844

[incanus]

Let's push this from b3; it's a nice hack, but let's take the time to do this right.

[datwelk]

Is this work in progress or still waiting to be picked up?

[friedbunny]

So far we've not added a legacy-raster-specific API for setting the map style and, at this point, I don't think that we will.

Have no fear, though, because this example shows how to use a Mapbox-hosted raster tile map with this SDK via a custom GL style.