Merge pull request #102 from uber/add-fitbounds

Add fitBounds

src/fit-bounds.js

@@ -0,0 +1,27 @@
+// NOTE: Transform is not a public API so we should be careful to always lock
+// down mapbox-gl to a specific major, minor, and patch version.
+import Transform from 'mapbox-gl/js/geo/transform';
+import {LngLatBounds, Point} from 'mapbox-gl';
+
+export default function fitBounds(width, height, _bounds, options) {
+  const bounds = new LngLatBounds([_bounds[0].reverse(), _bounds[1].reverse()]);
+  options = options || {};
+  const padding = typeof options.padding === 'undefined' ? 0 : options.padding;
+  const offset = Point.convert([0, 0]);
+  const tr = new Transform();
+  tr.width = width;
+  tr.height = height;
+  const nw = tr.project(bounds.getNorthWest());
+  const se = tr.project(bounds.getSouthEast());
+  const size = se.sub(nw);
+  const scaleX = (tr.width - padding * 2 - Math.abs(offset.x) * 2) / size.x;
+  const scaleY = (tr.height - padding * 2 - Math.abs(offset.y) * 2) / size.y;
+
+  const center = tr.unproject(nw.add(se).div(2));
+  const zoom = tr.scaleZoom(tr.scale * Math.min(scaleX, scaleY));
+  return {
+    latitude: center.lat,
+    longitude: center.lng,
+    zoom
+  };
+}

src/index.js

@@ -20,6 +20,8 @@
 
 import MapGL from './map.react';
 import * as overlays from './overlays';
+import fitBounds from './fit-bounds';
 
 module.exports = MapGL;
+module.exports.fitBounds = fitBounds;
 Object.assign(module.exports, overlays);