tween array fixes

src/Tween.js

@@ -216,7 +216,7 @@
         _addAttr: function(key, end) {
             var node = this.node,
                 nodeId = node._id,
-                start, diff, tweenId, n, len, trueEnd;
+                start, diff, tweenId, n, len, trueEnd, trueStart;
 
             // remove conflict from tween map if it exists
             tweenId = Konva.Tween.tweens[nodeId][key];
@@ -238,6 +238,7 @@
 
                     if (end.length > start.length) {
                         // so in this case we will increase number of starting points
+                        trueStart = start;
                         start = Konva.Util._prepareArrayForTween(start, end, node.closed());
                     } else {
                         // in this case we will increase number of eding points
@@ -267,7 +268,8 @@
                 start: start,
                 diff: diff,
                 end: end,
-                trueEnd: trueEnd
+                trueEnd: trueEnd,
+                trueStart: trueStart
             };
             Konva.Tween.tweens[nodeId][key] = this._id;
         },
@@ -330,6 +332,13 @@
                 }
             };
             this.tween.onReset = function() {
+                var node = that.node;
+                // after tweening  points of line we need to set original start
+                var attrs = Konva.Tween.attrs[node._id][that._id];
+                if (attrs.points && attrs.points.trueStart) {
+                    node.points(attrs.points.trueStart);
+                }
+
                 if (that.onReset) {
                     that.onReset();
                 }

test/unit/Tween-test.js

@@ -277,6 +277,63 @@ suite('Tween', function() {
                 }
             });
         });
+
+        test('tween array to lower size and go back', function(done) {
+            var stage = addStage();
+
+            var layer = new Konva.Layer();
+            stage.add(layer);
+
+            var line = new Konva.Line({
+                stroke: 'black',
+                points: [100, 100, 200, 100, 200, 200, 100, 200],
+                closed: true
+            });
+            layer.add(line);
+
+            var tween = new Konva.Tween({
+                node: line,
+                points: [100, 100, 200, 100, 200, 200],
+                duration: 0.01,
+                onFinish: function() {
+                    tween.reverse();
+                },
+                onReset: function() {
+                    assert.deepEqual(line.points(), [100, 100, 200, 100, 200, 200, 100, 200]);
+                    done();
+                }
+            });
+            tween.play();
+        });
+
+        test('tween array to bigger size and go back', function(done) {
+            var stage = addStage();
+
+            var layer = new Konva.Layer();
+            stage.add(layer);
+
+            var line = new Konva.Line({
+                stroke: 'black',
+                points: [100, 100, 200, 100, 200, 200],
+                closed: true
+            });
+            layer.add(line);
+
+            var tween = new Konva.Tween({
+                node: line,
+                points: [100, 100, 200, 100, 200, 200, 100, 200],
+                duration: 0.01,
+                onFinish: function() {
+                    tween.reverse();
+                },
+                onReset: function() {
+                    assert.deepEqual(line.points(), [100, 100, 200, 100, 200, 200]);
+                    done();
+                }
+            });
+            tween.play();
+        });
+
     });
 
 });