Bug 1658169 - Add a SmoothScrollAnimation that matches the main-thread smooth scroll physics. r=tnikkel

Differential Revision: https://phabricator.services.mozilla.com/D89666

gfx/layers/apz/src/AsyncPanZoomAnimation.h

@@ -12,6 +12,7 @@
 #include "mozilla/TimeStamp.h"
 #include "nsISupportsImpl.h"
 #include "nsTArray.h"
+#include "nsThreadUtils.h"
 
 namespace mozilla {
 namespace layers {
@@ -21,6 +22,7 @@ struct FrameMetrics;
 class WheelScrollAnimation;
 class KeyboardScrollAnimation;
 class SmoothMsdScrollAnimation;
+class SmoothScrollAnimation;
 
 class AsyncPanZoomAnimation {
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AsyncPanZoomAnimation)
@@ -75,6 +77,7 @@ class AsyncPanZoomAnimation {
   virtual SmoothMsdScrollAnimation* AsSmoothMsdScrollAnimation() {
     return nullptr;
   }
+  virtual SmoothScrollAnimation* AsSmoothScrollAnimation() { return nullptr; }
 
   virtual bool WantsRepaints() { return true; }
 

gfx/layers/apz/src/SmoothScrollAnimation.cpp

@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "SmoothScrollAnimation.h"
+#include "ScrollAnimationBezierPhysics.h"
+#include "mozilla/layers/APZPublicUtils.h"
+
+namespace mozilla {
+namespace layers {
+
+SmoothScrollAnimation::SmoothScrollAnimation(AsyncPanZoomController& aApzc,
+                                             const nsPoint& aInitialPosition,
+                                             ScrollOrigin aOrigin)
+    : GenericScrollAnimation(
+          aApzc, aInitialPosition,
+          apz::ComputeBezierAnimationSettingsForOrigin(aOrigin)),
+      mOrigin(aOrigin) {}
+
+SmoothScrollAnimation* SmoothScrollAnimation::AsSmoothScrollAnimation() {
+  return this;
+}
+
+ScrollOrigin SmoothScrollAnimation::GetScrollOrigin() const { return mOrigin; }
+
+}  // namespace layers
+}  // namespace mozilla

gfx/layers/apz/src/SmoothScrollAnimation.h

@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_layers_SmoothScrollAnimation_h_
+#define mozilla_layers_SmoothScrollAnimation_h_
+
+#include "GenericScrollAnimation.h"
+#include "mozilla/ScrollOrigin.h"
+
+namespace mozilla {
+namespace layers {
+
+class AsyncPanZoomController;
+
+class SmoothScrollAnimation : public GenericScrollAnimation {
+ public:
+  SmoothScrollAnimation(AsyncPanZoomController& aApzc,
+                        const nsPoint& aInitialPosition,
+                        ScrollOrigin aScrollOrigin);
+
+  SmoothScrollAnimation* AsSmoothScrollAnimation() override;
+  ScrollOrigin GetScrollOrigin() const;
+
+ private:
+  ScrollOrigin mOrigin;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // mozilla_layers_SmoothScrollAnimation_h_

gfx/layers/moz.build

@@ -382,6 +382,7 @@ UNIFIED_SOURCES += [
     'apz/src/SampledAPZCState.cpp',
     'apz/src/SimpleVelocityTracker.cpp',
     'apz/src/SmoothMsdScrollAnimation.cpp',
+    'apz/src/SmoothScrollAnimation.cpp',
     'apz/src/WheelScrollAnimation.cpp',
     'apz/testutil/APZTestData.cpp',
     'apz/util/ActiveElementManager.cpp',