[CRD iOS] Viewport fling animation

remoting/client/ios/client_gestures.mm

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 #import "remoting/client/ios/client_gestures.h"
 #import "remoting/client/ios/session/remoting_client.h"
@@ skipping 15 matching lines @@
   [view addGestureRecognizer:_longPressRecognizer];
 
   _panRecognizer = [[UIPanGestureRecognizer alloc]
       initWithTarget:self
               action:@selector(panGestureTriggered:)];
   _panRecognizer.minimumNumberOfTouches = 1;
   _panRecognizer.maximumNumberOfTouches = 2;
   _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:)];
   _threeFingerPanRecognizer.minimumNumberOfTouches = 3;
   _threeFingerPanRecognizer.maximumNumberOfTouches = 3;
   _threeFingerPanRecognizer.delegate = self;
   [view addGestureRecognizer:_threeFingerPanRecognizer];
 
   _pinchRecognizer = [[UIPinchGestureRecognizer alloc]
       initWithTarget:self
@@ skipping 67 matching lines @@
   }
 }
 
 - (IBAction)tapGestureTriggered:(UITapGestureRecognizer*)sender {
   CGPoint touchPoint = [sender locationInView:_view];
   _client.gestureInterpreter->Tap(touchPoint.x, touchPoint.y);
 }
 
 // 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);
 
     // Reset translation so next iteration is relative
     [sender setTranslation:CGPointZero inView:_view];
   }
 
   // LOG_TRACE(INFO) << "panGestureTriggered";
   //   CGPoint translation = [sender translationInView:self.view];
   //   // If we start with 2 touches, and the pinch gesture is not in progress
@@ skipping 82 matching lines @@
   //
   //   // Reset translation so next iteration is relative.  Wait until a changed
   //   // event in order to also capture the portion of the translation that
   //   occurred
   //   // between the Began and Changed States.
   //   if ([sender state] == UIGestureRecognizerStateChanged) {
   //     [sender setTranslation:CGPointZero inView:self.view];
   //   }
 }
 
+// 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];
   remoting::GestureInterpreter::GestureState state;
   switch ([sender state]) {
     case UIGestureRecognizerStateBegan:
       state = remoting::GestureInterpreter::GESTURE_BEGAN;
       break;
     case UIGestureRecognizerStateChanged:
       state = remoting::GestureInterpreter::GESTURE_CHANGED;
@@ skipping 84 matching lines @@
     shouldRecognizeSimultaneouslyWithGestureRecognizer:
         (UIGestureRecognizer*)otherGestureRecognizer {
   if (gestureRecognizer == _pinchRecognizer ||
       (gestureRecognizer == _panRecognizer)) {
     if (otherGestureRecognizer == _pinchRecognizer ||
         otherGestureRecognizer == _panRecognizer) {
       return YES;
     }
   }
 
+  if (gestureRecognizer == _flingRecognizer ||
+      (gestureRecognizer == _panRecognizer)) {
+    if (otherGestureRecognizer == _flingRecognizer ||
+        otherGestureRecognizer == _panRecognizer) {
+      return YES;
+    }
+  }
+
   if (gestureRecognizer == _longPressRecognizer ||
       gestureRecognizer == _panRecognizer) {
     if (otherGestureRecognizer == _longPressRecognizer ||
         otherGestureRecognizer == _panRecognizer) {
       return YES;
     }
   }
 
   if (gestureRecognizer == _twoFingerTapRecognizer &&
       otherGestureRecognizer == _longPressRecognizer) {
     return YES;
   }
 
   if (gestureRecognizer == _panRecognizer &&
       otherGestureRecognizer == _edgeGesture) {
     return YES;
   }
   // TODO(nicholss): If we return NO here, it dismisses the other reconizers.
   // As we add more types of reconizers, they need to be accounted for in the
   // above logic.
   return NO;
 }
 
 @end