New styles for use with OpenMapTiles and Stadia

## The files

* `style-microg-normal-openmaptiles.json` is a pure OpenMapTiles schema version of microG's custom style. The sources are set to Stadia but could be modified to be used with another schema-compliant vendor, e.g. MapTiler.

* `style-microg-normal-stadia.json` is a variant with Stadia custom layers.

* `style-microg-normal-mapbox.json` is a historic, unmaintained variant for use with Mapbox.

* `style-microg-sattelite-*.json` is the same, but with a sattelite layer (no openmaptiles variant, because openmaptiles does not specify a sattelite layer). **TODO: create these.**

* `sprite_sources` files can be generated to a single sprite file as found in the app's assets using `spreet` (see below).

* **TODO: remove references to mapbox for fonts.**

## Resources

### For creating styles

* Tool: https://maputnik.github.io/

* Style spec: https://maplibre.org/maplibre-style-spec/

	* https://maplibre.org/maplibre-style-spec/expressions/

* Style schema: **https://openmaptiles.org/schema/**

* Schema tileset explorer (requires maptiler login): https://cloud.maptiler.com/tiles/v3-openmaptiles/

#### Vendor-specific

* Mapbox

    * https://docs.mapbox.com/data/tilesets/reference/mapbox-streets-v8/

* Stadia

    * https://docs.stadiamaps.com/custom-styles/

    * https://docs.stadiamaps.com/tilesets/

### For converting assets

* https://github.com/flother/spreet

* https://github.com/stadiamaps/sdf_font_tools/tree/main/build_pbf_glyphs

Commands:

```

$ spreet sprite_sources/ ../../play-services-maps-core-mapbox/src/main/assets/sprites

$ spreet --retina sprite_sources/ ../../play-services-maps-core-mapbox/src/main/assets/sprites@2x

$ build_pbf_glyphs fonts/ ../../play-services-maps-core-mapbox/src/main/assets/

```

## Legal

* based on Mapbox Basic, part of the Mapbox Open Styles, licensed under

    * Style code: BSD license

    * Style virtual features / design: CC BY 3.0

    * Reference: https://github.com/mapbox/mapbox-gl-styles/blob/master/LICENSE.md

* derivation created by larma

* derivation created by /e/ foundation

* makes use of snippets from [Stadia's variant of OSM Bright](https://docs.stadiamaps.com/map-styles/osm-bright/), also a derivation of Mapbox Open Styles

	* Style code: BSD 3-Clause License

	* Style design: CC-BY 4.0

	* Reference: https://stadiamaps.com/attribution/

* fonts: Roboto family, licensed Apache 2.0, https://fonts.google.com/specimen/Roboto/about

<svg height="3.675mm" viewBox="0 0 3.675 3.675" width="3.675mm" xmlns="http://www.w3.org/2000/svg"><circle cx="1.8375" cy="1.8375" fill="#f1f1f1" r="1.5875" stroke="#000" stroke-linejoin="round" stroke-width=".5"/><circle cx="1.8375" cy="1.8375" r=".8375"/></svg>

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