[CRD iOS] Viewport fling animation

remoting/client/gesture_interpreter.cc

 // 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.
 
 #include "remoting/client/gesture_interpreter.h"
-#include "base/logging.h"
+
+#include "base/bind.h"
+#include "base/time/time.h"
 #include "remoting/client/direct_input_strategy.h"
 
+namespace {
+
+const float kOneFingerFlingTimeConstant = 325.f;
+
+}  // namespace
+
 namespace remoting {
-
 GestureInterpreter::GestureInterpreter(
     const DesktopViewport::TransformationCallback& on_transformation_changed,
     ChromotingSession* input_stub)
-    : input_stub_(input_stub) {
+    : input_stub_(input_stub),
+      pan_animation_(kOneFingerFlingTimeConstant,
+                     base::Bind(&GestureInterpreter::PanWithoutAbortAnimations,
+                                base::Unretained(this))) {
   viewport_.RegisterOnTransformationChangedCallback(on_transformation_changed,
                                                     true);
 
   // TODO(yuweih): This should be configurable.
   input_strategy_.reset(new DirectInputStrategy());
 }
 
 GestureInterpreter::~GestureInterpreter() {}
 
 void GestureInterpreter::Pinch(float pivot_x, float pivot_y, float scale) {
+  AbortAnimations();
   input_strategy_->HandlePinch(pivot_x, pivot_y, scale, &viewport_);
 }
 
 void GestureInterpreter::Pan(float translation_x, float translation_y) {
-  // TODO(yuweih): Pan deceleration animation.
-  input_strategy_->HandlePan(translation_x, translation_y, is_dragging_mode_,
-                             &viewport_);
+  AbortAnimations();
+  PanWithoutAbortAnimations(translation_x, translation_y);
 }
 
 void GestureInterpreter::Tap(float x, float y) {
+  AbortAnimations();
   float cursor_x, cursor_y;
   input_strategy_->FindCursorPositions(x, y, viewport_, &cursor_x, &cursor_y);
   InjectMouseClick(cursor_x, cursor_y,
                    protocol::MouseEvent_MouseButton_BUTTON_LEFT);
 }
 
 void GestureInterpreter::TwoFingerTap(float x, float y) {
+  AbortAnimations();
   float cursor_x, cursor_y;
   input_strategy_->FindCursorPositions(x, y, viewport_, &cursor_x, &cursor_y);
   InjectMouseClick(cursor_x, cursor_y,
                    protocol::MouseEvent_MouseButton_BUTTON_RIGHT);
 }
 
 void GestureInterpreter::LongPress(float x, float y, GestureState state) {
+  AbortAnimations();
   float cursor_x, cursor_y;
   input_strategy_->FindCursorPositions(x, y, viewport_, &cursor_x, &cursor_y);
 
   is_dragging_mode_ = state != GESTURE_ENDED;
   input_stub_->SendMouseEvent(cursor_x, cursor_y,
                               protocol::MouseEvent_MouseButton_BUTTON_LEFT,
                               is_dragging_mode_);
 }
 
-void GestureInterpreter::InjectMouseClick(
-    float x,
-    float y,
-    protocol::MouseEvent_MouseButton button) {
-  input_stub_->SendMouseEvent(x, y, button, true);
-  input_stub_->SendMouseEvent(x, y, button, false);
+void GestureInterpreter::OneFingerFling(float velocity_x, float velocity_y) {
+  AbortAnimations();
+  pan_animation_.SetVelocity(velocity_x, velocity_y);
+  pan_animation_.Tick();
+}
+
+void GestureInterpreter::ProcessAnimations() {
+  if (pan_animation_.IsAnimationInProgress()) {
+    pan_animation_.Tick();
+  }
 }
 
 void GestureInterpreter::OnSurfaceSizeChanged(int width, int height) {
   viewport_.SetSurfaceSize(width, height);
 }
 
 void GestureInterpreter::OnDesktopSizeChanged(int width, int height) {
   viewport_.SetDesktopSize(width, height);
 }
 
+void GestureInterpreter::PanWithoutAbortAnimations(float translation_x,
+                                                   float translation_y) {
+  input_strategy_->HandlePan(translation_x, translation_y, is_dragging_mode_,
+                             &viewport_);
+}
+
+void GestureInterpreter::AbortAnimations() {
+  pan_animation_.Abort();
+}
+
+void GestureInterpreter::InjectMouseClick(
+    float x,
+    float y,
+    protocol::MouseEvent_MouseButton button) {
+  input_stub_->SendMouseEvent(x, y, button, true);
+  input_stub_->SendMouseEvent(x, y, button, false);
+}
+
 }  // namespace remoting