v4 raster layers load with low-resolution tiles on high-resolution screens

[1ec5]

#916 removed a special case for HiDPI that bumped up the zoom level, the idea being that vector tiles have a sufficiently high resolution that the HiDPI experience wouldn’t suffer. But this same code runs for raster layers. Now the Satellite layer is half as sharp:

[1ec5]

It should be possible to stick a “{ratio}” somewhere in the URL so that TileData::request() will insert @2x. The 2x variant does at least exist for mapbox.satellite – can we depend on its existence in general?

[incanus]

Yes, @2x is supported for any Mapbox-hosted raster tile. If it's a custom tile that's uploaded not from OSM-based stuff, it'll fail silently, but for everything else, it'll work.

[1ec5]

@incanus how silently? Will we need to fall back to a 1× URL or will mapbox just return a 1× tile anyways?

[incanus]

The latter. I'd say supporting non-auto-retina raster tiles in GL is not a major use case so this is fine.

[jfirebaugh]

All Mapbox v4 raster tiles support @2x.

Relevant JS code: 1, 2

[incanus]

I'm talking about such cases as this justin.NACIS2012, which I created in TileMill and uploaded rasters of.

1x:

2x:

So, the sizing is just naively blown up, but the URL works.

I'd be on the creator to create a 2x good-looking version (which I did at justin.NACIS2012Retina).