Allow forEachFeatureAtPixel callback to break out of loop

src/ol/renderer/canvas/canvasvectorlayerrenderer.js

@@ -85,14 +85,16 @@ ol.renderer.canvas.VectorLayer.prototype.composeFrame =
  * @inheritDoc
  */
 ol.renderer.canvas.VectorLayer.prototype.forEachFeatureAtPixel =
-    function(pixel, callback) {
-  if (!goog.isNull(this.replayGroup_)) {
+    function(pixel, callback, opt_obj) {
+  if (goog.isNull(this.replayGroup_)) {
+    return undefined;
+  } else {
     goog.asserts.assert(!ol.extent.isEmpty(this.renderedExtent_));
     goog.asserts.assert(!isNaN(this.renderedResolution_));
     var coordinate = this.getMap().getCoordinateFromPixel(pixel);
     var renderGeometryFunction = this.getRenderGeometryFunction_();
     goog.asserts.assert(goog.isFunction(renderGeometryFunction));
-    this.replayGroup_.forEachGeometryAtCoordinate(this.renderedExtent_,
+    return this.replayGroup_.forEachGeometryAtCoordinate(this.renderedExtent_,
         this.renderedResolution_, coordinate, renderGeometryFunction,
         /**
          * @param {ol.geom.Geometry} geometry Geometry.
@@ -101,7 +103,7 @@ ol.renderer.canvas.VectorLayer.prototype.forEachFeatureAtPixel =
         function(geometry, data) {
           var feature = /** @type {ol.Feature} */ (data);
           goog.asserts.assert(goog.isDef(feature));
-          callback(feature);
+          return callback.call(opt_obj, feature);
         });
   }
 };

src/ol/renderer/layerrenderer.js

@@ -44,7 +44,10 @@ goog.inherits(ol.renderer.Layer, goog.Disposable);
 
 /**
  * @param {ol.Pixel} pixel Pixel.
- * @param {function(ol.Feature)} callback Feature callback.
+ * @param {function(this: S, ol.Feature): T} callback Feature callback.
+ * @param {S=} opt_obj Scope.
+ * @return {T|undefined} Callback result.
+ * @template S,T
  */
 ol.renderer.Layer.prototype.forEachFeatureAtPixel = goog.nullFunction;
 

src/ol/renderer/maprenderer.js

@@ -80,13 +80,30 @@ ol.renderer.Map.prototype.disposeInternal = function() {
 
 /**
  * @param {ol.Pixel} pixel Pixel.
- * @param {function(ol.Feature)} callback Feature callback.
+ * @param {function(this: S, ol.Feature): T} callback Feature callback.
+ * @param {S=} opt_obj Scope.
+ * @return {T|undefined} Callback result.
+ * @template S,T
  */
 ol.renderer.Map.prototype.forEachFeatureAtPixel =
-    function(pixel, callback) {
-  goog.object.forEach(this.layerRenderers_, function(layerRenderer) {
-    layerRenderer.forEachFeatureAtPixel(pixel, callback);
-  });
+    function(pixel, callback, opt_obj) {
+  var layers = this.map_.getLayers();
+  if (goog.isDef(layers)) {
+    var layersArray = layers.getArray();
+    var i;
+    for (i = layersArray.length - 1; i >= 0; --i) {
+      var layer = layersArray[i];
+      if (layer.getVisible()) {
+        var layerRenderer = this.getLayerRenderer(layer);
+        var result =
+            layerRenderer.forEachFeatureAtPixel(pixel, callback, opt_obj);
+        if (result) {
+          return result;
+        }
+      }
+    }
+  }
+  return undefined;
 };