Merge pull request #1124 from tschaub/xyz

Allow tilegrid creation from projection or extent.

externs/olx.js

@@ -5092,19 +5092,48 @@ olx.tilegrid.WMTSOptions.prototype.tileSizes;
 
 
 /**
- * @typedef {{maxZoom: number}}
+ * @typedef {{extent: (ol.Extent|undefined),
+ *     maxZoom: (number|undefined),
+ *     minZoom: (number|undefined),
+ *     tileSize: (number|undefined)}}
  * @api
  */
 olx.tilegrid.XYZOptions;
 
 
 /**
- * Maximum zoom.
- * @type {number}
+ * 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 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.  The default is `ol.DEFAULT_MAX_ZOOM`.  This determines the
+ * number of levels in the grid set.  For example, a `maxZoom` of 21 means there
+ * are 22 levels in the grid set.
+ * @type {number|undefined}
  */
 olx.tilegrid.XYZOptions.prototype.maxZoom;
 
 
+/**
+ * Minimum zoom. Default is 0.
+ * @type {number|undefined}
+ */
+olx.tilegrid.XYZOptions.prototype.minZoom;
+
+
+/**
+ * Tile size in pixels. Default is 256. (Only square tiles are supported.)
+ * @type {number|undefined}
+ */
+olx.tilegrid.XYZOptions.prototype.tileSize;
+
+
 /**
  * @typedef {{resolutions: !Array.<number>}}
  * @api