diff --git a/src/viewer.js b/src/viewer.js
index ab782484..5384cb4f 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -2544,22 +2544,25 @@ function onCanvasDrag( event ) {
 }
 
 function onCanvasDragEnd( event ) {
-    var gestureSettings;
-
-    if ( !event.preventDefaultAction && this.viewport ) {
-        gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
-        if ( gestureSettings.flickEnabled && event.speed >= gestureSettings.flickMinSpeed ) {
-            var amplitudeX = gestureSettings.flickMomentum * ( event.speed * Math.cos( event.direction - (Math.PI / 180 * this.viewport.degrees) ) ),
-                amplitudeY = gestureSettings.flickMomentum * ( event.speed * Math.sin( event.direction - (Math.PI / 180 * this.viewport.degrees) ) ),
-                center = this.viewport.pixelFromPoint( this.viewport.getCenter( true ) ),
-                target = this.viewport.pointFromPixel( new $.Point( center.x - amplitudeX, center.y - amplitudeY ) );
-            if( !this.panHorizontal ) {
-                target.x = center.x;
+    if (!event.preventDefaultAction && this.viewport) {
+        var gestureSettings = this.gestureSettingsByDeviceType(event.pointerType);
+        if (gestureSettings.flickEnabled &&
+            event.speed >= gestureSettings.flickMinSpeed) {
+            var amplitudeX = 0;
+            if (this.panHorizontal) {
+                amplitudeX = gestureSettings.flickMomentum * event.speed *
+                    Math.cos(event.direction);
             }
-            if( !this.panVertical ) {
-                target.y = center.y;
+            var amplitudeY = 0;
+            if (this.panVertical) {
+                amplitudeY = gestureSettings.flickMomentum * event.speed *
+                    Math.sin(event.direction);
             }
-            this.viewport.panTo( target, false );
+            var center = this.viewport.pixelFromPoint(
+                this.viewport.getCenter(true));
+            var target = this.viewport.pointFromPixel(
+                new $.Point(center.x - amplitudeX, center.y - amplitudeY));
+            this.viewport.panTo(target, false);
         }
         this.viewport.applyConstraints();
     }
@@ -2578,7 +2581,7 @@ function onCanvasDragEnd( event ) {
      * @property {Object} originalEvent - The original DOM event.
      * @property {?Object} userData - Arbitrary subscriber-defined object.
      */
-    this.raiseEvent( 'canvas-drag-end', {
+    this.raiseEvent('canvas-drag-end', {
         tracker: event.eventSource,
         position: event.position,
         speed: event.speed,