From e752a88be1ad24545472a2ad93283741724e3962 Mon Sep 17 00:00:00 2001
From: Young Hahn <young@mapbox.com>
Date: Thu, 21 Jan 2016 15:18:14 -0500
Subject: [PATCH] Allow using tileSize: 512 as a switch to trade retina support
 for 512px raster tiles

---
 js/source/raster_tile_source.js | 2 +-
 js/util/mapbox.js               | 8 ++++++--
 test/js/util/mapbox.test.js     | 8 ++++++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/js/source/raster_tile_source.js b/js/source/raster_tile_source.js
index 03a3b82c8a1..c6cb4acfdd8 100644
--- a/js/source/raster_tile_source.js
+++ b/js/source/raster_tile_source.js
@@ -51,7 +51,7 @@ RasterTileSource.prototype = util.inherit(Evented, {
     getTile: Source._getTile,
 
     _loadTile: function(tile) {
-        var url = normalizeURL(tile.coord.url(this.tiles), this.url);
+        var url = normalizeURL(tile.coord.url(this.tiles), this.url, this.tileSize);
 
         tile.request = ajax.getImage(url, done.bind(this));
 
diff --git a/js/util/mapbox.js b/js/util/mapbox.js
index 367f7c61079..66330f5d010 100644
--- a/js/util/mapbox.js
+++ b/js/util/mapbox.js
@@ -65,11 +65,15 @@ module.exports.normalizeSpriteURL = function(url, format, ext, accessToken) {
     return normalizeURL('mapbox://' + user + '/' + style + draft + '/sprite' + format + ext, '/styles/v1/', accessToken);
 };
 
-module.exports.normalizeTileURL = function(url, sourceUrl) {
+module.exports.normalizeTileURL = function(url, sourceUrl, tileSize) {
     if (!sourceUrl || !sourceUrl.match(/^mapbox:\/\//))
         return url;
 
+    // The v4 mapbox tile API supports 512x512 image tiles only when @2x
+    // is appended to the tile URL. If `tileSize: 512` is specified for
+    // a Mapbox raster source force the @2x suffix even if a non hidpi
+    // device.
     url = url.replace(/([?&]access_token=)tk\.[^&]+/, '$1' + config.ACCESS_TOKEN);
     var extension = browser.supportsWebp ? 'webp' : '$1';
-    return url.replace(/\.((?:png|jpg)\d*)(?=$|\?)/, browser.devicePixelRatio >= 2 ? '@2x.' + extension : '.' + extension);
+    return url.replace(/\.((?:png|jpg)\d*)(?=$|\?)/, browser.devicePixelRatio >= 2 || tileSize === 512 ? '@2x.' + extension : '.' + extension);
 };
diff --git a/test/js/util/mapbox.test.js b/test/js/util/mapbox.test.js
index f2e4d3a6b3b..82ca124586d 100644
--- a/test/js/util/mapbox.test.js
+++ b/test/js/util/mapbox.test.js
@@ -119,6 +119,14 @@ test("mapbox", function(t) {
             t.end();
         });
 
+        t.test('inserts @2x when tileSize == 512', function(t) {
+            t.equal(mapbox.normalizeTileURL('http://path.png/tile.png', mapboxSource, 512), 'http://path.png/tile@2x.png');
+            t.equal(mapbox.normalizeTileURL('http://path.png/tile.png32', mapboxSource, 512), 'http://path.png/tile@2x.png32');
+            t.equal(mapbox.normalizeTileURL('http://path.png/tile.jpg70', mapboxSource, 512), 'http://path.png/tile@2x.jpg70');
+            t.equal(mapbox.normalizeTileURL('http://path.png/tile.png?access_token=foo', mapboxSource, 512), 'http://path.png/tile@2x.png?access_token=foo');
+            t.end();
+        });
+
         t.test('replaces img extension with webp on supporting devices', function(t) {
             browser.supportsWebp = true;
             t.equal(mapbox.normalizeTileURL('http://path.png/tile.png', mapboxSource), 'http://path.png/tile.webp');