Merge pull request #1975 from fredj/rotation-anchor

Rotate around arbitrary coordinate

src/ol/animation.js

@@ -4,6 +4,7 @@ goog.provide('ol.animation');
 
 goog.require('ol.PreRenderFunction');
 goog.require('ol.ViewHint');
+goog.require('ol.coordinate');
 goog.require('ol.easing');
 
 
@@ -87,11 +88,13 @@ ol.animation.pan = function(options) {
  * @todo stability experimental
  */
 ol.animation.rotate = function(options) {
-  var sourceRotation = options.rotation;
+  var sourceRotation = goog.isDef(options.rotation) ? options.rotation : 0;
   var start = goog.isDef(options.start) ? options.start : goog.now();
   var duration = goog.isDef(options.duration) ? options.duration : 1000;
   var easing = goog.isDef(options.easing) ?
       options.easing : ol.easing.inAndOut;
+  var anchor = goog.isDef(options.anchor) ?
+      options.anchor : null;
 
   return (
       /**
@@ -106,9 +109,15 @@ ol.animation.rotate = function(options) {
         } else if (frameState.time < start + duration) {
           var delta = 1 - easing((frameState.time - start) / duration);
           var deltaRotation =
-              sourceRotation - frameState.view2DState.rotation;
+              (sourceRotation - frameState.view2DState.rotation) * delta;
           frameState.animate = true;
-          frameState.view2DState.rotation += delta * deltaRotation;
+          frameState.view2DState.rotation += deltaRotation;
+          if (!goog.isNull(anchor)) {
+            var center = frameState.view2DState.center;
+            ol.coordinate.sub(center, anchor);
+            ol.coordinate.rotate(center, deltaRotation);
+            ol.coordinate.add(center, anchor);
+          }
           frameState.viewHints[ol.ViewHint.ANIMATING] += 1;
           return true;
         } else {

src/ol/coordinate.js

@@ -182,6 +182,18 @@ ol.coordinate.scale = function(coordinate, s) {
 };
 
 
+/**
+ * @param {ol.Coordinate} coordinate Coordinate.
+ * @param {ol.Coordinate} delta Delta.
+ * @return {ol.Coordinate} Coordinate.
+ */
+ol.coordinate.sub = function(coordinate, delta) {
+  coordinate[0] -= delta[0];
+  coordinate[1] -= delta[1];
+  return coordinate;
+};
+
+
 /**
  * @param {ol.Coordinate} coord1 First coordinate.
  * @param {ol.Coordinate} coord2 Second coordinate.

src/ol/interaction/interaction.js

@@ -128,11 +128,7 @@ ol.interaction.Interaction.rotateWithoutConstraints =
       }
     }
     goog.asserts.assertInstanceof(view, ol.View2D);
-    if (goog.isDefAndNotNull(opt_anchor)) {
-      var center = view.calculateCenterRotate(rotation, opt_anchor);
-      view.setCenter(center);
-    }
-    view.setRotation(rotation);
+    view.rotate(rotation, opt_anchor);
   }
 };
 

src/ol/view2d.exports

@@ -7,4 +7,5 @@
 @exportProperty ol.View2D.prototype.centerOn
 @exportProperty ol.View2D.prototype.getView2D
 @exportProperty ol.View2D.prototype.getZoom
+@exportProperty ol.View2D.prototype.rotate
 @exportProperty ol.View2D.prototype.setZoom

src/ol/view2d.js

@@ -534,6 +534,20 @@ ol.View2D.prototype.isDef = function() {
 };
 
 
+/**
+ * Rotate the view around a given coordinate.
+ * @param {number} rotation New rotation value for the view.
+ * @param {ol.Coordinate=} opt_anchor The rotation center.
+ */
+ol.View2D.prototype.rotate = function(rotation, opt_anchor) {
+  if (goog.isDef(opt_anchor)) {
+    var center = this.calculateCenterRotate(rotation, opt_anchor);
+    this.setCenter(center);
+  }
+  this.setRotation(rotation);
+};
+
+
 /**
  * Set the center of the current view.
  * @param {ol.Coordinate|undefined} center Center.