Adding Loc.add method.

src/ol/Loc.js

@@ -120,6 +120,22 @@ ol.Loc.prototype.doTransform = function(proj) {
     return new ol.Loc(point['x'], point['y'], this.z_, proj);
 };
 
+/**
+ * Adds the passed x, y(, z) delta to a new location.
+ *
+ * @param {number} x
+ * @param {number} y
+ * @param {number=} opt_z
+ * @returns {ol.Loc}
+ */
+ol.Loc.prototype.add = function(x, y, opt_z) {
+    var newZ;
+    if (goog.isDef(this.z_)) {
+        newZ = (opt_z || 0) + this.z_;
+    }
+    return new ol.Loc(this.x_ + x, this.y_ + y, newZ, this.projection_);
+};
+
 /**
  * Clean up.
  * @export

src/ol/Map.js

@@ -327,10 +327,9 @@ ol.Map.prototype.setZoom = function(zoom, opt_anchor) {
         var size = this.getSize(),
             anchorLoc = this.getLocForPixel(opt_anchor),
             newRes = this.getResolutionForZoom(newZoom);
-        newCenter = new ol.Loc(
+        newCenter = anchorLoc.add(
-            anchorLoc.getX() + (size.width/2 - opt_anchor.x) * newRes,
+            (size.width/2 - opt_anchor.x) * newRes,
-            anchorLoc.getY() - (size.height/2 - opt_anchor.y) * newRes,
+            (opt_anchor.y - size.height/2) * newRes
-            undefined, this.getProjection()
         );
     } else {
         newCenter = this.center_;

src/ol/renderer/MapRenderer.js

@@ -89,10 +89,9 @@ ol.renderer.MapRenderer.prototype.getLocForPixel = function(pixel) {
     var center = this.renderedCenter_,
         resolution = this.renderedResolution_,
         size = goog.style.getSize(this.container_);
-    return new ol.Loc(
+    return center.add(
-        center.getX() - (size.width/2 - pixel.x)*resolution,
+        (pixel.x - size.width/2) * resolution,
-        center.getY() + (size.height/2 - pixel.y)*resolution,
+        (size.height/2 - pixel.y) * resolution
-        undefined, this.renderedCenter_.getProjection()
     );
 };