[CRD iOS] Viewport fling animation

remoting/client/gesture_interpreter.h

 // 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.
 
 #ifndef REMOTING_CLIENT_GESTURE_INTERPRETER_H_
 #define REMOTING_CLIENT_GESTURE_INTERPRETER_H_
 
 #include <memory>
 
 #include "remoting/client/chromoting_session.h"
 #include "remoting/client/desktop_viewport.h"
+#include "remoting/client/fling_animation.h"
 #include "remoting/proto/event.pb.h"
 
 namespace remoting {
 
 class InputStrategy;
 
 // This is a class for interpreting a raw touch input into actions like moving
 // the viewport and injecting mouse clicks.
 class GestureInterpreter {
  public:
   enum GestureState { GESTURE_BEGAN, GESTURE_CHANGED, GESTURE_ENDED };
 
   GestureInterpreter(
       const DesktopViewport::TransformationCallback& on_transformation_changed,
       ChromotingSession* input_stub);
   ~GestureInterpreter();
 
   // Coordinates of the OpenGL view surface will be used.
+
+  // This can happen in conjunction with Pan().
   void Pinch(float pivot_x, float pivot_y, float scale);
+
+  // Called whenever the user did a pan gesture. It can be one-finger pan, no
+  // matter long-press in on or not, or two-finger pan in conjunction with the
+  // pinch gesture. Two-finger pan without pinch is consider a scroll gesture.
   void Pan(float translation_x, float translation_y);
+
+  // Called when the user did a one-finger tap.
   void Tap(float x, float y);
+
   void TwoFingerTap(float x, float y);
 
   // Caller is expected to call both Pan() and LongPress() when long-press is in
   // progress.
   void LongPress(float x, float y, GestureState state);
 
+  // Called when the user has just done a one-finger pan (no long-press or
+  // pinching) and the pan gesture still has some final velocity.
+  void OneFingerFling(float velocity_x, float velocity_y);
+
+  // Called to process one animation frame.
+  void ProcessAnimations();
+
   void OnSurfaceSizeChanged(int width, int height);
   void OnDesktopSizeChanged(int width, int height);
 
  private:
+  void PanWithoutAbortAnimations(float translation_x, float translation_y);
+
+  void AbortAnimations();
+
   void InjectMouseClick(float x,
                         float y,
                         protocol::MouseEvent_MouseButton button);
 
   std::unique_ptr<InputStrategy> input_strategy_;
   DesktopViewport viewport_;
   ChromotingSession* input_stub_;
   bool is_dragging_mode_ = false;
 
+  FlingAnimation pan_animation_;
+
   // GestureInterpreter is neither copyable nor movable.
   GestureInterpreter(const GestureInterpreter&) = delete;
   GestureInterpreter& operator=(const GestureInterpreter&) = delete;
 };
 
 }  // namespace remoting
 #endif  // REMOTING_CLIENT_GESTURE_INTERPRETER_H_