[CRD iOS] Viewport fling animation

remoting/client/ios/client_gestures.mm

Index: remoting/client/ios/client_gestures.mm
diff --git a/remoting/client/ios/client_gestures.mm b/remoting/client/ios/client_gestures.mm
index f67beac120a2cc9807ceb13a42f3bd796d5dc2e5..5c912020a10d8cce4312fdfb1b3caa074c36a287 100644
--- a/remoting/client/ios/client_gestures.mm
+++ b/remoting/client/ios/client_gestures.mm
@@ -33,6 +33,14 @@
   _panRecognizer.delegate = self;
   [view addGestureRecognizer:_panRecognizer];
 
+  _flingRecognizer = [[UIPanGestureRecognizer alloc]
+      initWithTarget:self
+              action:@selector(flingGestureTriggered:)];
+  _flingRecognizer.minimumNumberOfTouches = 1;
+  _flingRecognizer.maximumNumberOfTouches = 1;
+  _flingRecognizer.delegate = self;
+  [view addGestureRecognizer:_flingRecognizer];
+
   _threeFingerPanRecognizer = [[UIPanGestureRecognizer alloc]
       initWithTarget:self
               action:@selector(threeFingerPanGestureTriggered:)];
@@ -120,12 +128,8 @@
 
 // Change position of scene.  This can occur during a pinch or long press.
 // Or perform a Mouse Wheel Scroll.
-// TODO(yuweih): The comment above doesn't seem right. Non-panning gestures
-//     should be moved out of this method.
 - (IBAction)panGestureTriggered:(UIPanGestureRecognizer*)sender {
-  // TODO(yuweih): Need deceleration animation, probably in another class.
-  if ([sender state] == UIGestureRecognizerStateChanged &&
-      [sender numberOfTouches] == 1) {
+  if ([sender state] == UIGestureRecognizerStateChanged) {

[Yuwei, 2017/05/10 06:53:03]

Removed the |numberOfTouches| check since it seems to work totally fine when the
user makes a pinch-and-pan gesture.

     CGPoint translation = [sender translationInView:_view];
     _client.gestureInterpreter->Pan(translation.x, translation.y);
 
@@ -228,6 +232,15 @@
   //   }
 }
 
+// Do fling on the viewport. This will happen at the end of the one-finger
+// panning.
+- (IBAction)flingGestureTriggered:(UIPanGestureRecognizer*)sender {
+  if ([sender state] == UIGestureRecognizerStateEnded) {
+    CGPoint velocity = [sender velocityInView:_view];
+    _client.gestureInterpreter->OneFingerFling(velocity.x, velocity.y);
+  }
+}
+
 // Click-Drag mouse operation.  This can occur during a Pan.
 - (IBAction)longPressGestureTriggered:(UILongPressGestureRecognizer*)sender {
   CGPoint touchPoint = [sender locationInView:_view];
@@ -332,6 +345,14 @@
     }
   }
 
+  if (gestureRecognizer == _flingRecognizer ||
+      (gestureRecognizer == _panRecognizer)) {
+    if (otherGestureRecognizer == _flingRecognizer ||
+        otherGestureRecognizer == _panRecognizer) {
+      return YES;
+    }
+  }
+
   if (gestureRecognizer == _longPressRecognizer ||
       gestureRecognizer == _panRecognizer) {
     if (otherGestureRecognizer == _longPressRecognizer ||