Sources may be configured with a projection, tile grids with an extent

An XYZ tile grid is constructed with an extent defining the bounds of the tile grid.

externs/olx.js

@@ -5092,14 +5092,24 @@ olx.tilegrid.WMTSOptions.prototype.tileSizes;
 
 
 /**
- * @typedef {{maxZoom: (number|undefined),
+ * @typedef {{extent: (ol.Extent|undefined),
- *     minZoom: (number|undefined),
+ *     maxZoom: (number|undefined),
- *     projection: (ol.proj.ProjectionLike|undefined)}}
+ *     minZoom: (number|undefined)}}
  * @api
  */
 olx.tilegrid.XYZOptions;
 
 
+/**
+ * Extent for the tile grid.  The origin for an XYZ tile grid is the top-left
+ * corner of the extent.  The zero level of the grid is defined by the
+ * resolution at which one 256 x 256 tile fits in the provided extent.  If not
+ * provided, the extent of the EPSG:3857 projection is used.
+ * @type {ol.Extent|undefined}
+ */
+olx.tilegrid.XYZOptions.prototype.extent;
+
+
 /**
  * Maximum zoom.
  * @type {number|undefined}
@@ -5114,13 +5124,6 @@ olx.tilegrid.XYZOptions.prototype.maxZoom;
 olx.tilegrid.XYZOptions.prototype.minZoom;
 
 
-/**
- * Projection.  Default is `'EPSG:3857'`.
- * @type {ol.proj.ProjectionLike|undefined}
- */
-olx.tilegrid.XYZOptions.prototype.projection;
-
-
 /**
  * @typedef {{resolutions: !Array.<number>}}
  * @api

src/ol/source/bingmapssource.js

@@ -89,7 +89,9 @@ ol.source.BingMaps.prototype.handleImageryMetadataResponse =
   var resource = response.resourceSets[0].resources[0];
 
   goog.asserts.assert(resource.imageWidth == resource.imageHeight);
+  var sourceProjection = this.getProjection();
   var tileGrid = new ol.tilegrid.XYZ({
+    extent: ol.tilegrid.extentFromProjection(sourceProjection),
     minZoom: resource.zoomMin,
     maxZoom: resource.zoomMax,
     tileSize: resource.imageWidth
@@ -97,7 +99,6 @@ ol.source.BingMaps.prototype.handleImageryMetadataResponse =
   this.tileGrid = tileGrid;
 
   var culture = this.culture_;
-  var sourceProjection = this.getProjection();
   this.tileUrlFunction = ol.TileUrlFunction.withTileCoordTransform(
       tileGrid.createTileCoordTransform(),
       ol.TileUrlFunction.createFromTileUrlFunctions(

src/ol/source/tilejsonsource.js

@@ -54,10 +54,11 @@ ol.source.TileJSON.prototype.handleTileJSONResponse = function(tileJSON) {
 
   var epsg4326Projection = ol.proj.get('EPSG:4326');
 
+  var sourceProjection = this.getProjection();
   var extent;
   if (goog.isDef(tileJSON.bounds)) {
     var transform = ol.proj.getTransformFromProjections(
-        epsg4326Projection, this.getProjection());
+        epsg4326Projection, sourceProjection);
     extent = ol.extent.applyTransform(tileJSON.bounds, transform);
   }
 
@@ -67,6 +68,7 @@ ol.source.TileJSON.prototype.handleTileJSONResponse = function(tileJSON) {
   var minZoom = tileJSON.minzoom || 0;
   var maxZoom = tileJSON.maxzoom || 22;
   var tileGrid = new ol.tilegrid.XYZ({
+    extent: ol.tilegrid.extentFromProjection(sourceProjection),
     maxZoom: maxZoom,
     minZoom: minZoom
   });

src/ol/source/xyzsource.js

@@ -17,13 +17,12 @@ goog.require('ol.tilegrid.XYZ');
  * @api
  */
 ol.source.XYZ = function(options) {
-
   var projection = goog.isDef(options.projection) ?
       options.projection : 'EPSG:3857';
 
   var tileGrid = new ol.tilegrid.XYZ({
-    maxZoom: options.maxZoom,
+    extent: ol.tilegrid.extentFromProjection(projection),
-    projection: options.projection
+    maxZoom: options.maxZoom
   });
 
   goog.base(this, {

src/ol/tilegrid/xyztilegrid.js

@@ -7,6 +7,7 @@ goog.require('ol.TileRange');
 goog.require('ol.extent');
 goog.require('ol.extent.Corner');
 goog.require('ol.proj');
+goog.require('ol.proj.EPSG3857');
 goog.require('ol.tilecoord');
 goog.require('ol.tilegrid.TileGrid');
 
@@ -23,19 +24,16 @@ goog.require('ol.tilegrid.TileGrid');
  * @api
  */
 ol.tilegrid.XYZ = function(options) {
-  var projection = goog.isDef(options.projection) ?
+  // TODO: accept a tileSize option
-      options.projection : 'EPSG:3857';
-  var extent = ol.tilegrid.extentFromProjection(projection);
-
   var tileSize = ol.DEFAULT_TILE_SIZE;
+  var extent = goog.isDef(options.extent) ?
+      options.extent : ol.proj.EPSG3857.EXTENT;
   var resolutions = ol.tilegrid.resolutionsFromExtent(
       extent, options.maxZoom, tileSize);
 
-  var origin = ol.extent.getCorner(extent, ol.extent.Corner.TOP_LEFT);
-
   goog.base(this, {
     minZoom: options.minZoom,
-    origin: origin,
+    origin: ol.extent.getCorner(extent, ol.extent.Corner.TOP_LEFT),
     resolutions: resolutions,
     tileSize: tileSize
   });