Handle attribution visiblity for tile layers

src/ol/tile/bingmaps.js

@@ -5,6 +5,7 @@ goog.require('goog.Uri');
 goog.require('goog.events');
 goog.require('goog.events.EventType');
 goog.require('goog.net.Jsonp');
+goog.require('ol.TileCoverageArea');
 goog.require('ol.TileLayer');
 goog.require('ol.TileStore');
 goog.require('ol.tilegrid.XYZ');
@@ -117,7 +118,8 @@ ol.tilestore.BingMaps.prototype.handleImageryMetadataResponse =
   var zoomMin = resource.zoomMin;
   var zoomMax = resource.zoomMax;
   var tileSize = new ol.Size(resource.imageWidth, resource.imageHeight);
-  this.tileGrid = new ol.tilegrid.XYZ(zoomMax, tileSize);
+  var tileGrid = new ol.tilegrid.XYZ(zoomMax, tileSize);
+  this.tileGrid = tileGrid;
 
   this.tileUrlFunction = ol.TileUrlFunction.withTileCoordTransform(
       function(tileCoord) {
@@ -162,7 +164,7 @@ ol.tilestore.BingMaps.prototype.handleImageryMetadataResponse =
               var extent = new ol.Extent(bbox[1], bbox[0], bbox[3], bbox[2]);
               var minZ = coverageArea.zoomMin;
               var maxZ = coverageArea.zoomMax;
-              return new ol.CoverageArea(extent, minZ, maxZ);
+              return new ol.TileCoverageArea(tileGrid, extent, minZ, maxZ);
             });
         return new ol.Attribution(html, coverageAreas, projection);
       });

src/ol/tile/tilecoveragearea.js

@@ -0,0 +1,59 @@
+goog.provide('ol.TileCoverageArea');
+
+goog.require('ol.CoverageArea');
+goog.require('ol.Extent');
+goog.require('ol.TileGrid');
+
+
+
+/**
+ * @constructor
+ * @extends {ol.CoverageArea}
+ * @param {ol.TileGrid} tileGrid Tile grid.
+ * @param {ol.Extent} extent Extent.
+ * @param {number} minZ Minimum Z.
+ * @param {number} maxZ Maximum Z.
+ */
+ol.TileCoverageArea = function(tileGrid, extent, minZ, maxZ) {
+
+  goog.base(this, extent);
+
+  /**
+   * @private
+   * @type {ol.TileGrid}
+   */
+  this.tileGrid_ = tileGrid;
+
+  /**
+   * @type {number}
+   */
+  this.minZ = minZ;
+
+  /**
+   * @type {number}
+   */
+  this.maxZ = maxZ;
+
+};
+goog.inherits(ol.TileCoverageArea, ol.CoverageArea);
+
+
+/**
+ * @inheritDoc
+ */
+ol.TileCoverageArea.prototype.intersectsExtentAndResolution =
+    function(extent, resolution) {
+  var z = this.tileGrid_.getZForResolution(resolution);
+  return this.minZ <= z && z <= this.maxZ &&
+      goog.base(this, 'intersectsExtentAndResolution', extent, resolution);
+};
+
+
+/**
+ * @param {ol.TransformFunction} transformFn Transform.
+ * @return {ol.TileCoverageArea} Transformed tile coverage area.
+ */
+ol.TileCoverageArea.prototype.transform = function(transformFn) {
+  var extent = this.extent.transform(transformFn);
+  return new ol.TileCoverageArea(this.tileGrid_, extent, this.minZ, this.maxZ);
+};