Make scroll animation less "drunk"

Tries to use the new bezier curves to approximate our old smooth
scrolling behavior.

Change-Id: I3b319025fb0339ec95c0a29525f2dde0631866ed
Reviewed-by: Michael Brüning <michael.bruning@theqtcompany.com>

6 files changed, 27 insertions, 11 deletions

diff --git a/chromium/cc/animation/scroll_offset_animation_curve.cc b/chromium/cc/animation/scroll_offset_animation_curve.cc
index 1b4d045c74c..a74a03f1f11 100644
--- a/chromium/cc/animation/scroll_offset_animation_curve.cc
+++ b/chromium/cc/animation/scroll_offset_animation_curve.cc
@@ -56,13 +56,13 @@ static float MaximumDimension(const gfx::Vector2dF& delta) {
 
 static std::unique_ptr<TimingFunction> EaseInOutWithInitialSlope(double slope) {
   // Clamp slope to a sane value.
-  slope = base::ClampToRange(slope, -1000.0, 1000.0);
+  slope = base::ClampToRange(slope, -100.0, 100.0);
 
-  // Based on CubicBezierTimingFunction::EaseType::EASE_IN_OUT preset
+  // Based on CubicBezierTimingFunction::EaseType::EASE_OUT_NATURAL preset
   // with first control point scaled.
-  const double x1 = 0.42;
+  const double x1 = 0.25;
   const double y1 = slope * x1;
-  return CubicBezierTimingFunction::Create(x1, y1, 0.58, 1);
+  return CubicBezierTimingFunction::Create(x1, y1, 0.45, 0.94);
 }
 
 std::unique_ptr<TimingFunction> ImpulseCurveWithInitialSlope(double slope) {
@@ -141,13 +141,17 @@ ScrollOffsetAnimationCurve::ScrollOffsetAnimationCurve(
       duration_behavior_(duration_behavior),
       has_set_initial_value_(false) {
   DCHECK_EQ((animation_type == AnimationType::kEaseInOut ||
-             animation_type == AnimationType::kImpulse),
+             animation_type == AnimationType::kImpulse || animation_type_ == AnimationType::kEaseOutNatural),
             duration_behavior.has_value());
   switch (animation_type) {
     case AnimationType::kEaseInOut:
       timing_function_ = CubicBezierTimingFunction::CreatePreset(
           CubicBezierTimingFunction::EaseType::EASE_IN_OUT);
       break;
+    case AnimationType::kEaseOutNatural:
+      timing_function_ = CubicBezierTimingFunction::CreatePreset(
+          CubicBezierTimingFunction::EaseType::EASE_OUT_NATURAL);
+      break;
     case AnimationType::kLinear:
       timing_function_ = LinearTimingFunction::Create();
       break;
@@ -168,7 +172,7 @@ ScrollOffsetAnimationCurve::ScrollOffsetAnimationCurve(
       duration_behavior_(duration_behavior),
       has_set_initial_value_(false) {
   DCHECK_EQ((animation_type == AnimationType::kEaseInOut ||
-             animation_type == AnimationType::kImpulse),
+             animation_type == AnimationType::kImpulse || animation_type_ == AnimationType::kEaseOutNatural),
             duration_behavior.has_value());
 }
 
@@ -229,6 +233,8 @@ base::TimeDelta ScrollOffsetAnimationCurve::SegmentDuration(
     base::TimeDelta delayed_by,
     absl::optional<double> velocity) {
   switch (animation_type_) {
+    case AnimationType::kEaseOutNatural:
+      // FIXME Check!
     case AnimationType::kEaseInOut:
       DCHECK(duration_behavior_.has_value());
       return EaseInOutSegmentDuration(delta, duration_behavior_.value(),
@@ -389,7 +395,7 @@ void ScrollOffsetAnimationCurve::UpdateTarget(
   base::TimeDelta delayed_by = std::max(base::TimeDelta(), last_retarget_ - t);
   t = std::max(t, last_retarget_);
 
-  if (animation_type_ == AnimationType::kEaseInOut &&
+  if ((animation_type_ == AnimationType::kEaseInOut || animation_type_ == AnimationType::kEaseOutNatural) &&
       std::abs(MaximumDimension(target_value_.DeltaFrom(new_target))) <
           kEpsilon) {
     // Don't update the animation if the new target is the same as the old one.
@@ -439,7 +445,8 @@ void ScrollOffsetAnimationCurve::UpdateTarget(
       velocity * (new_duration.InSecondsF() / MaximumDimension(new_delta));
 
   DCHECK(animation_type_ == AnimationType::kImpulse ||
-         animation_type_ == AnimationType::kEaseInOut);
+         animation_type_ == AnimationType::kEaseInOut ||
+         animation_type_ == AnimationType::kEaseOutNatural);
   if (animation_type_ == AnimationType::kImpulse &&
       IsNewTargetInOppositeDirection(current_position, target_value_,
                                      new_target)) {
diff --git a/chromium/cc/animation/scroll_offset_animation_curve.h b/chromium/cc/animation/scroll_offset_animation_curve.h
index e1ec50fa85e..2b9896e2247 100644
--- a/chromium/cc/animation/scroll_offset_animation_curve.h
+++ b/chromium/cc/animation/scroll_offset_animation_curve.h
@@ -118,7 +118,7 @@ class CC_ANIMATION_EXPORT ScrollOffsetAnimationCurve
   FRIEND_TEST_ALL_PREFIXES(ScrollOffsetAnimationCurveTest,
                            ImpulseUpdateTargetSwitchDirections);
   friend class ScrollOffsetAnimationCurveFactory;
-  enum class AnimationType { kLinear, kEaseInOut, kImpulse };
+  enum class AnimationType { kLinear, kEaseInOut, kImpulse, kEaseOutNatural };
 
   // |duration_behavior| should be provided if (and only if) |animation_type| is
   // kEaseInOut.
diff --git a/chromium/cc/animation/scroll_offset_animation_curve_factory.cc b/chromium/cc/animation/scroll_offset_animation_curve_factory.cc
index 469792b5d83..f893b4b2efb 100644
--- a/chromium/cc/animation/scroll_offset_animation_curve_factory.cc
+++ b/chromium/cc/animation/scroll_offset_animation_curve_factory.cc
@@ -72,7 +72,7 @@ ScrollOffsetAnimationCurveFactory::CreateEaseInOutAnimation(
     const gfx::ScrollOffset& target_value,
     ScrollOffsetAnimationCurve::DurationBehavior duration_behavior) {
   return base::WrapUnique(new ScrollOffsetAnimationCurve(
-      target_value, ScrollOffsetAnimationCurve::AnimationType::kEaseInOut,
+      target_value, ScrollOffsetAnimationCurve::AnimationType::kEaseOutNatural,
       duration_behavior));
 }
 
diff --git a/chromium/third_party/blink/renderer/platform/animation/timing_function.cc b/chromium/third_party/blink/renderer/platform/animation/timing_function.cc
index d61c9fa12c6..35520c8aef3 100644
--- a/chromium/third_party/blink/renderer/platform/animation/timing_function.cc
+++ b/chromium/third_party/blink/renderer/platform/animation/timing_function.cc
@@ -37,6 +37,9 @@ CubicBezierTimingFunction* CubicBezierTimingFunction::Preset(
   DEFINE_STATIC_REF(
       CubicBezierTimingFunction, ease_in_out,
       (base::AdoptRef(new CubicBezierTimingFunction(EaseType::EASE_IN_OUT))));
+  DEFINE_STATIC_REF(
+      CubicBezierTimingFunction, ease_out_natural,
+      (base::AdoptRef(new CubicBezierTimingFunction(EaseType::EASE_OUT_NATURAL))));
 
   switch (ease_type) {
     case EaseType::EASE:
@@ -47,6 +50,8 @@ CubicBezierTimingFunction* CubicBezierTimingFunction::Preset(
       return ease_out;
     case EaseType::EASE_IN_OUT:
       return ease_in_out;
+    case EaseType::EASE_OUT_NATURAL:
+      return ease_out_natural;
     default:
       NOTREACHED();
       return nullptr;
@@ -63,6 +68,7 @@ String CubicBezierTimingFunction::ToString() const {
       return "ease-out";
     case CubicBezierTimingFunction::EaseType::EASE_IN_OUT:
       return "ease-in-out";
+    case CubicBezierTimingFunction::EaseType::EASE_OUT_NATURAL:
     case CubicBezierTimingFunction::EaseType::CUSTOM:
       return "cubic-bezier(" + String::NumberToStringECMAScript(X1()) + ", " +
              String::NumberToStringECMAScript(Y1()) + ", " +
diff --git a/chromium/ui/gfx/animation/keyframe/timing_function.cc b/chromium/ui/gfx/animation/keyframe/timing_function.cc
index 9650a501bd6..2122ddb7432 100644
--- a/chromium/ui/gfx/animation/keyframe/timing_function.cc
+++ b/chromium/ui/gfx/animation/keyframe/timing_function.cc
@@ -34,6 +34,9 @@ CubicBezierTimingFunction::CreatePreset(EaseType ease_type) {
     case EaseType::EASE_IN_OUT:
       return base::WrapUnique(
           new CubicBezierTimingFunction(ease_type, 0.42, 0.0, 0.58, 1));
+    case EaseType::EASE_OUT_NATURAL:
+      return base::WrapUnique(
+          new CubicBezierTimingFunction(ease_type, 0.26, 0.46, 0.45, 0.94));
     default:
       NOTREACHED();
       return nullptr;
diff --git a/chromium/ui/gfx/animation/keyframe/timing_function.h b/chromium/ui/gfx/animation/keyframe/timing_function.h
index 7ce71331dfe..e08faf805e9 100644
--- a/chromium/ui/gfx/animation/keyframe/timing_function.h
+++ b/chromium/ui/gfx/animation/keyframe/timing_function.h
@@ -37,7 +37,7 @@ class GFX_KEYFRAME_ANIMATION_EXPORT TimingFunction {
 class GFX_KEYFRAME_ANIMATION_EXPORT CubicBezierTimingFunction
     : public TimingFunction {
  public:
-  enum class EaseType { EASE, EASE_IN, EASE_OUT, EASE_IN_OUT, CUSTOM };
+  enum class EaseType { EASE, EASE_IN, EASE_OUT, EASE_IN_OUT, EASE_OUT_NATURAL, CUSTOM };
 
   static std::unique_ptr<CubicBezierTimingFunction> CreatePreset(
       EaseType ease_type);