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/* -*- 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
#include "Axis.h"
#include <math.h> // for fabsf, pow, powf
#include <algorithm> // for max
#include "APZCTreeManager.h" // for APZCTreeManager
#include "AsyncPanZoomController.h" // for AsyncPanZoomController
#include "FrameMetrics.h" // for FrameMetrics
#include "SimpleVelocityTracker.h" // for FrameMetrics
#include "mozilla/Attributes.h" // for final
#include "mozilla/Preferences.h" // for Preferences
#include "mozilla/gfx/Rect.h" // for RoundedIn
#include "mozilla/layers/APZThreadUtils.h" // for AssertOnControllerThread
#include "mozilla/mozalloc.h" // for operator new
#include "nsMathUtils.h" // for NS_lround
#include "nsPrintfCString.h" // for nsPrintfCString
#include "nsThreadUtils.h" // for NS_DispatchToMainThread, etc
#include "nscore.h" // for NS_IMETHOD
static mozilla::LazyLogModule sApzAxsLog("apz.axis");
#define AXIS_LOG(...) MOZ_LOG(sApzAxsLog, LogLevel::Debug, (__VA_ARGS__))
namespace mozilla {
namespace layers {
bool FuzzyEqualsCoordinate(CSSCoord aValue1, CSSCoord aValue2) {
return FuzzyEqualsAdditive(aValue1, aValue2, COORDINATE_EPSILON) ||
FuzzyEqualsMultiplicative(aValue1, aValue2);
}
Axis::Axis(AsyncPanZoomController* aAsyncPanZoomController)
: mPos(0),
mVelocity(0.0f, "Axis::mVelocity"),
mAxisLocked(false),
mAsyncPanZoomController(aAsyncPanZoomController),
mOverscroll(0),
mMSDModel(0.0, 0.0, 0.0, StaticPrefs::apz_overscroll_spring_stiffness(),
StaticPrefs::apz_overscroll_damping()),
mVelocityTracker(mAsyncPanZoomController->GetPlatformSpecificState()
->CreateVelocityTracker(this)) {}
float Axis::ToLocalVelocity(float aVelocityInchesPerMs) const {
ScreenPoint velocity =
MakePoint(aVelocityInchesPerMs * mAsyncPanZoomController->GetDPI());
// Use ToScreenCoordinates() to convert a point rather than a vector by
// treating the point as a vector, and using (0, 0) as the anchor.
ScreenPoint panStart = mAsyncPanZoomController->ToScreenCoordinates(
mAsyncPanZoomController->PanStart(), ParentLayerPoint());
ParentLayerPoint localVelocity =
mAsyncPanZoomController->ToParentLayerCoordinates(velocity, panStart);
return localVelocity.Length();
}
void Axis::UpdateWithTouchAtDevicePoint(ParentLayerCoord aPos,
TimeStamp aTimestamp) {
// mVelocityTracker is controller-thread only
APZThreadUtils::AssertOnControllerThread();
mPos = aPos;
AXIS_LOG("%p|%s got position %f\n", mAsyncPanZoomController, Name(),
mPos.value);
if (Maybe<float> newVelocity =
mVelocityTracker->AddPosition(aPos, aTimestamp)) {
DoSetVelocity(mAxisLocked ? 0 : *newVelocity);
AXIS_LOG("%p|%s velocity from tracker is %f%s\n", mAsyncPanZoomController,
Name(), *newVelocity,
mAxisLocked ? ", but we are axis locked" : "");
}
}
void Axis::StartTouch(ParentLayerCoord aPos, TimeStamp aTimestamp) {
mStartPos = aPos;
mPos = aPos;
mVelocityTracker->StartTracking(aPos, aTimestamp);
mAxisLocked = false;
}
bool Axis::AdjustDisplacement(ParentLayerCoord aDisplacement,
ParentLayerCoord& aDisplacementOut,
ParentLayerCoord& aOverscrollAmountOut,
bool aForceOverscroll /* = false */) {
if (mAxisLocked) {
aOverscrollAmountOut = 0;
aDisplacementOut = 0;
return false;
}
if (aForceOverscroll) {
aOverscrollAmountOut = aDisplacement;
aDisplacementOut = 0;
return false;
}
ParentLayerCoord displacement = aDisplacement;
// First consume any overscroll in the opposite direction along this axis.
ParentLayerCoord consumedOverscroll = 0;
if (mOverscroll > 0 && aDisplacement < 0) {
consumedOverscroll = std::min(mOverscroll, -aDisplacement);
} else if (mOverscroll < 0 && aDisplacement > 0) {
consumedOverscroll = 0.f - std::min(-mOverscroll, aDisplacement);
}
mOverscroll -= consumedOverscroll;
displacement += consumedOverscroll;
if (consumedOverscroll != 0.0f) {
AXIS_LOG("%p|%s changed overscroll amount to %f\n", mAsyncPanZoomController,
Name(), mOverscroll.value);
}
// Split the requested displacement into an allowed displacement that does
// not overscroll, and an overscroll amount.
aOverscrollAmountOut = DisplacementWillOverscrollAmount(displacement);
if (aOverscrollAmountOut != 0.0f) {
// No need to have a velocity along this axis anymore; it won't take us
// anywhere, so we're just spinning needlessly.
AXIS_LOG("%p|%s has overscrolled, clearing velocity\n",
mAsyncPanZoomController, Name());
DoSetVelocity(0.0f);
displacement -= aOverscrollAmountOut;
}
aDisplacementOut = displacement;
return fabsf(consumedOverscroll) > EPSILON;
}
ParentLayerCoord Axis::ApplyResistance(
ParentLayerCoord aRequestedOverscroll) const {
// 'resistanceFactor' is a value between 0 and 1/16, which:
// - tends to 1/16 as the existing overscroll tends to 0
// - tends to 0 as the existing overscroll tends to the composition length
// The actual overscroll is the requested overscroll multiplied by this
// factor.
float resistanceFactor =
(1 - fabsf(GetOverscroll()) / GetCompositionLength()) / 16;
float result = resistanceFactor < 0 ? ParentLayerCoord(0)
: aRequestedOverscroll * resistanceFactor;
result = clamped(result, -8.0f, 8.0f);
return result;
}
void Axis::OverscrollBy(ParentLayerCoord aOverscroll) {
MOZ_ASSERT(CanScroll());
// We can get some spurious calls to OverscrollBy() with near-zero values
// due to rounding error. Ignore those (they might trip the asserts below.)
if (mAsyncPanZoomController->IsZero(aOverscroll)) {
return;
}
EndOverscrollAnimation();
aOverscroll = ApplyResistance(aOverscroll);
if (aOverscroll > 0) {
#ifdef DEBUG
if (!IsScrolledToEnd()) {
nsPrintfCString message(
"composition end (%f) is not equal (within error) to page end (%f)\n",
GetCompositionEnd().value, GetPageEnd().value);
NS_ASSERTION(false, message.get());
MOZ_CRASH("GFX: Overscroll issue > 0");
}
#endif
MOZ_ASSERT(mOverscroll >= 0);
} else if (aOverscroll < 0) {
#ifdef DEBUG
if (!IsScrolledToStart()) {
nsPrintfCString message(
"composition origin (%f) is not equal (within error) to page origin "
"(%f)\n",
GetOrigin().value, GetPageStart().value);
NS_ASSERTION(false, message.get());
MOZ_CRASH("GFX: Overscroll issue < 0");
}
#endif
MOZ_ASSERT(mOverscroll <= 0);
}
mOverscroll += aOverscroll;
AXIS_LOG("%p|%s changed overscroll amount to %f\n", mAsyncPanZoomController,
Name(), mOverscroll.value);
}
ParentLayerCoord Axis::GetOverscroll() const { return mOverscroll; }
void Axis::RestoreOverscroll(ParentLayerCoord aOverscroll) {
mOverscroll = aOverscroll;
}
void Axis::StartOverscrollAnimation(float aVelocity) {
const float maxVelocity = StaticPrefs::apz_overscroll_max_velocity();
aVelocity = clamped(aVelocity / 2.0f, -maxVelocity, maxVelocity);
SetVelocity(aVelocity);
mMSDModel.SetPosition(mOverscroll);
// Convert velocity from ParentLayerCoords/millisecond to
// ParentLayerCoords/second.
mMSDModel.SetVelocity(DoGetVelocity() * 1000.0);
AXIS_LOG(
"%p|%s beginning overscroll animation with amount %f and velocity %f\n",
mAsyncPanZoomController, Name(), mOverscroll.value, DoGetVelocity());
}
void Axis::EndOverscrollAnimation() {
mMSDModel.SetPosition(0.0);
mMSDModel.SetVelocity(0.0);
}
bool Axis::SampleOverscrollAnimation(const TimeDuration& aDelta,
SideBits aOverscrollSideBits) {
mMSDModel.Simulate(aDelta);
mOverscroll = mMSDModel.GetPosition();
if (((aOverscrollSideBits & (SideBits::eTop | SideBits::eLeft)) &&
mOverscroll > 0) ||
((aOverscrollSideBits & (SideBits::eBottom | SideBits::eRight)) &&
mOverscroll < 0)) {
// Stop the overscroll model immediately if it's going to get across the
// boundary.
mMSDModel.SetPosition(0.0);
mMSDModel.SetVelocity(0.0);
}
AXIS_LOG("%p|%s changed overscroll amount to %f\n", mAsyncPanZoomController,
Name(), mOverscroll.value);
if (mMSDModel.IsFinished(1.0)) {
// "Jump" to the at-rest state. The jump shouldn't be noticeable as the
// velocity and overscroll are already low.
AXIS_LOG("%p|%s oscillation dropped below threshold, going to rest\n",
mAsyncPanZoomController, Name());
ClearOverscroll();
DoSetVelocity(0);
return false;
}
// Otherwise, continue the animation.
return true;
}
bool Axis::IsOverscrollAnimationRunning() const {
return !mMSDModel.IsFinished(1.0);
}
bool Axis::IsOverscrollAnimationAlive() const {
// Unlike IsOverscrollAnimationRunning, check the position and the velocity to
// be sure that the animation has started but hasn't yet finished.
return mMSDModel.GetPosition() != 0.0 || mMSDModel.GetVelocity() != 0.0;
}
bool Axis::IsOverscrolled() const { return mOverscroll != 0.f; }
bool Axis::IsScrolledToStart() const {
const auto zoom = GetFrameMetrics().GetZoom();
if (zoom == CSSToParentLayerScale(0)) {
return true;
}
return FuzzyEqualsCoordinate(GetOrigin() / zoom, GetPageStart() / zoom);
}
bool Axis::IsScrolledToEnd() const {
const auto zoom = GetFrameMetrics().GetZoom();
if (zoom == CSSToParentLayerScale(0)) {
return true;
}
return FuzzyEqualsCoordinate(GetCompositionEnd() / zoom, GetPageEnd() / zoom);
}
bool Axis::IsInInvalidOverscroll() const {
if (mOverscroll > 0) {
return !IsScrolledToEnd();
} else if (mOverscroll < 0) {
return !IsScrolledToStart();
}
return false;
}
void Axis::ClearOverscroll() {
EndOverscrollAnimation();
mOverscroll = 0;
}
ParentLayerCoord Axis::PanStart() const { return mStartPos; }
ParentLayerCoord Axis::PanDistance() const { return fabs(mPos - mStartPos); }
ParentLayerCoord Axis::PanDistance(ParentLayerCoord aPos) const {
return fabs(aPos - mStartPos);
}
void Axis::EndTouch(TimeStamp aTimestamp, ClearAxisLock aClearAxisLock) {
// mVelocityQueue is controller-thread only
APZThreadUtils::AssertOnControllerThread();
// If the velocity tracker wasn't able to compute a velocity, zero out
// the velocity to make sure we don't get a fling based on some old and
// no-longer-relevant value of mVelocity. Also if the axis is locked then
// just reset the velocity to 0 since we don't need any velocity to carry
// into the fling.
if (mAxisLocked) {
DoSetVelocity(0);
} else if (Maybe<float> velocity =
mVelocityTracker->ComputeVelocity(aTimestamp)) {
DoSetVelocity(*velocity);
} else {
DoSetVelocity(0);
}
if (aClearAxisLock == ClearAxisLock::Yes) {
mAxisLocked = false;
}
AXIS_LOG("%p|%s ending touch, computed velocity %f\n",
mAsyncPanZoomController, Name(), DoGetVelocity());
}
void Axis::CancelGesture() {
// mVelocityQueue is controller-thread only
APZThreadUtils::AssertOnControllerThread();
AXIS_LOG("%p|%s cancelling touch, clearing velocity queue\n",
mAsyncPanZoomController, Name());
DoSetVelocity(0.0f);
mVelocityTracker->Clear();
SetAxisLocked(false);
}
bool Axis::CanScroll() const {
return mAsyncPanZoomController->FuzzyGreater(GetPageLength(),
GetCompositionLength());
}
bool Axis::CanScroll(CSSCoord aDelta) const {
return CanScroll(aDelta * GetFrameMetrics().GetZoom());
}
bool Axis::CanScroll(ParentLayerCoord aDelta) const {
if (!CanScroll()) {
return false;
}
const auto zoom = GetFrameMetrics().GetZoom();
CSSCoord availableToScroll = 0;
if (zoom != CSSToParentLayerScale(0)) {
availableToScroll =
ParentLayerCoord(
fabs(DisplacementWillOverscrollAmount(aDelta) - aDelta)) /
zoom;
}
return availableToScroll > COORDINATE_EPSILON;
}
CSSCoord Axis::ClampOriginToScrollableRect(CSSCoord aOrigin) const {
CSSToParentLayerScale zoom = GetFrameMetrics().GetZoom();
ParentLayerCoord origin = aOrigin * zoom;
ParentLayerCoord result;
if (origin < GetPageStart()) {
result = GetPageStart();
} else if (origin + GetCompositionLength() > GetPageEnd()) {
result = GetPageEnd() - GetCompositionLength();
} else {
return aOrigin;
}
if (zoom == CSSToParentLayerScale(0)) {
return aOrigin;
}
return result / zoom;
}
bool Axis::CanScrollNow() const { return !mAxisLocked && CanScroll(); }
ParentLayerCoord Axis::DisplacementWillOverscrollAmount(
ParentLayerCoord aDisplacement) const {
ParentLayerCoord newOrigin = GetOrigin() + aDisplacement;
ParentLayerCoord newCompositionEnd = GetCompositionEnd() + aDisplacement;
// If the current pan plus a displacement takes the window to the left of or
// above the current page rect.
bool minus = newOrigin < GetPageStart();
// If the current pan plus a displacement takes the window to the right of or
// below the current page rect.
bool plus = newCompositionEnd > GetPageEnd();
if (minus && plus) {
// Don't handle overscrolled in both directions; a displacement can't cause
// this, it must have already been zoomed out too far.
return 0;
}
if (minus) {
return newOrigin - GetPageStart();
}
if (plus) {
return newCompositionEnd - GetPageEnd();
}
return 0;
}
CSSCoord Axis::ScaleWillOverscrollAmount(float aScale, CSSCoord aFocus) const {
// Internally, do computations in ParentLayer coordinates *before* the scale
// is applied.
CSSToParentLayerScale zoom = GetFrameMetrics().GetZoom();
ParentLayerCoord focus = aFocus * zoom;
ParentLayerCoord originAfterScale = (GetOrigin() + focus) - (focus / aScale);
bool both = ScaleWillOverscrollBothSides(aScale);
bool minus = GetPageStart() - originAfterScale > COORDINATE_EPSILON;
bool plus =
(originAfterScale + (GetCompositionLength() / aScale)) - GetPageEnd() >
COORDINATE_EPSILON;
if ((minus && plus) || both) {
// If we ever reach here it's a bug in the client code.
MOZ_ASSERT(false,
"In an OVERSCROLL_BOTH condition in ScaleWillOverscrollAmount");
return 0;
}
if (minus && zoom != CSSToParentLayerScale(0)) {
return (originAfterScale - GetPageStart()) / zoom;
}
if (plus && zoom != CSSToParentLayerScale(0)) {
return (originAfterScale + (GetCompositionLength() / aScale) -
GetPageEnd()) /
zoom;
}
return 0;
}
bool Axis::IsAxisLocked() const { return mAxisLocked; }
float Axis::GetVelocity() const { return mAxisLocked ? 0 : DoGetVelocity(); }
void Axis::SetVelocity(float aVelocity) {
AXIS_LOG("%p|%s direct-setting velocity to %f\n", mAsyncPanZoomController,
Name(), aVelocity);
DoSetVelocity(aVelocity);
}
ParentLayerCoord Axis::GetCompositionEnd() const {
return GetOrigin() + GetCompositionLength();
}
ParentLayerCoord Axis::GetPageEnd() const {
return GetPageStart() + GetPageLength();
}
ParentLayerCoord Axis::GetScrollRangeEnd() const {
return GetPageEnd() - GetCompositionLength();
}
ParentLayerCoord Axis::GetOrigin() const {
ParentLayerPoint origin =
GetFrameMetrics().GetVisualScrollOffset() * GetFrameMetrics().GetZoom();
return GetPointOffset(origin);
}
ParentLayerCoord Axis::GetCompositionLength() const {
return GetRectLength(GetFrameMetrics().GetCompositionBounds());
}
ParentLayerCoord Axis::GetPageStart() const {
ParentLayerRect pageRect = GetFrameMetrics().GetExpandedScrollableRect() *
GetFrameMetrics().GetZoom();
return GetRectOffset(pageRect);
}
ParentLayerCoord Axis::GetPageLength() const {
ParentLayerRect pageRect = GetFrameMetrics().GetExpandedScrollableRect() *
GetFrameMetrics().GetZoom();
return GetRectLength(pageRect);
}
bool Axis::ScaleWillOverscrollBothSides(float aScale) const {
const FrameMetrics& metrics = GetFrameMetrics();
ParentLayerRect screenCompositionBounds =
metrics.GetCompositionBounds() / ParentLayerToParentLayerScale(aScale);
return GetRectLength(screenCompositionBounds) - GetPageLength() >
COORDINATE_EPSILON;
}
float Axis::DoGetVelocity() const {
auto velocity = mVelocity.Lock();
return velocity.ref();
}
void Axis::DoSetVelocity(float aVelocity) {
auto velocity = mVelocity.Lock();
velocity.ref() = aVelocity;
}
const FrameMetrics& Axis::GetFrameMetrics() const {
return mAsyncPanZoomController->GetFrameMetrics();
}
const ScrollMetadata& Axis::GetScrollMetadata() const {
return mAsyncPanZoomController->GetScrollMetadata();
}
bool Axis::OverscrollBehaviorAllowsHandoff() const {
// Scroll handoff is a "non-local" overscroll behavior, so it's allowed
// with "auto" and disallowed with "contain" and "none".
return GetOverscrollBehavior() == OverscrollBehavior::Auto;
}
bool Axis::OverscrollBehaviorAllowsOverscrollEffect() const {
// An overscroll effect is a "local" overscroll behavior, so it's allowed
// with "auto" and "contain" and disallowed with "none".
return GetOverscrollBehavior() != OverscrollBehavior::None;
}
AxisX::AxisX(AsyncPanZoomController* aAsyncPanZoomController)
: Axis(aAsyncPanZoomController) {}
CSSCoord AxisX::GetPointOffset(const CSSPoint& aPoint) const {
return aPoint.x;
}
OuterCSSCoord AxisX::GetPointOffset(const OuterCSSPoint& aPoint) const {
return aPoint.x;
}
ParentLayerCoord AxisX::GetPointOffset(const ParentLayerPoint& aPoint) const {
return aPoint.x;
}
CSSToParentLayerScale AxisX::GetAxisScale(
const CSSToParentLayerScale2D& aScale) const {
return CSSToParentLayerScale(aScale.xScale);
}
ParentLayerCoord AxisX::GetRectLength(const ParentLayerRect& aRect) const {
return aRect.Width();
}
CSSCoord AxisX::GetRectLength(const CSSRect& aRect) const {
return aRect.Width();
}
ParentLayerCoord AxisX::GetRectOffset(const ParentLayerRect& aRect) const {
return aRect.X();
}
CSSCoord AxisX::GetRectOffset(const CSSRect& aRect) const { return aRect.X(); }
float AxisX::GetTransformScale(
const AsyncTransformComponentMatrix& aMatrix) const {
return aMatrix._11;
}
ParentLayerCoord AxisX::GetTransformTranslation(
const AsyncTransformComponentMatrix& aMatrix) const {
return aMatrix._41;
}
void AxisX::PostScale(AsyncTransformComponentMatrix& aMatrix,
float aScale) const {
aMatrix.PostScale(aScale, 1.f, 1.f);
}
void AxisX::PostTranslate(AsyncTransformComponentMatrix& aMatrix,
ParentLayerCoord aTranslation) const {
aMatrix.PostTranslate(aTranslation, 0, 0);
}
ScreenPoint AxisX::MakePoint(ScreenCoord aCoord) const {
return ScreenPoint(aCoord, 0);
}
const char* AxisX::Name() const { return "X"; }
bool AxisX::CanScrollTo(Side aSide) const {
switch (aSide) {
case eSideLeft:
return CanScroll(CSSCoord(-COORDINATE_EPSILON * 2));
case eSideRight:
return CanScroll(CSSCoord(COORDINATE_EPSILON * 2));
default:
MOZ_ASSERT_UNREACHABLE("aSide is out of valid values");
return false;
}
}
SideBits AxisX::ScrollableDirections() const {
SideBits directions = SideBits::eNone;
if (CanScrollTo(eSideLeft)) {
directions |= SideBits::eLeft;
}
if (CanScrollTo(eSideRight)) {
directions |= SideBits::eRight;
}
return directions;
}
OverscrollBehavior AxisX::GetOverscrollBehavior() const {
return GetScrollMetadata().GetOverscrollBehavior().mBehaviorX;
}
AxisY::AxisY(AsyncPanZoomController* aAsyncPanZoomController)
: Axis(aAsyncPanZoomController) {}
CSSCoord AxisY::GetPointOffset(const CSSPoint& aPoint) const {
return aPoint.y;
}
OuterCSSCoord AxisY::GetPointOffset(const OuterCSSPoint& aPoint) const {
return aPoint.y;
}
ParentLayerCoord AxisY::GetPointOffset(const ParentLayerPoint& aPoint) const {
return aPoint.y;
}
CSSToParentLayerScale AxisY::GetAxisScale(
const CSSToParentLayerScale2D& aScale) const {
return CSSToParentLayerScale(aScale.yScale);
}
ParentLayerCoord AxisY::GetRectLength(const ParentLayerRect& aRect) const {
return aRect.Height();
}
CSSCoord AxisY::GetRectLength(const CSSRect& aRect) const {
return aRect.Height();
}
ParentLayerCoord AxisY::GetRectOffset(const ParentLayerRect& aRect) const {
return aRect.Y();
}
CSSCoord AxisY::GetRectOffset(const CSSRect& aRect) const { return aRect.Y(); }
float AxisY::GetTransformScale(
const AsyncTransformComponentMatrix& aMatrix) const {
return aMatrix._22;
}
ParentLayerCoord AxisY::GetTransformTranslation(
const AsyncTransformComponentMatrix& aMatrix) const {
return aMatrix._42;
}
void AxisY::PostScale(AsyncTransformComponentMatrix& aMatrix,
float aScale) const {
aMatrix.PostScale(1.f, aScale, 1.f);
}
void AxisY::PostTranslate(AsyncTransformComponentMatrix& aMatrix,
ParentLayerCoord aTranslation) const {
aMatrix.PostTranslate(0, aTranslation, 0);
}
ScreenPoint AxisY::MakePoint(ScreenCoord aCoord) const {
return ScreenPoint(0, aCoord);
}
const char* AxisY::Name() const { return "Y"; }
bool AxisY::CanScrollTo(Side aSide) const {
switch (aSide) {
case eSideTop:
return CanScroll(CSSCoord(-COORDINATE_EPSILON * 2));
case eSideBottom:
return CanScroll(CSSCoord(COORDINATE_EPSILON * 2));
default:
MOZ_ASSERT_UNREACHABLE("aSide is out of valid values");
return false;
}
}
SideBits AxisY::ScrollableDirections() const {
SideBits directions = SideBits::eNone;
if (CanScrollTo(eSideTop)) {
directions |= SideBits::eTop;
}
if (CanScrollTo(eSideBottom)) {
directions |= SideBits::eBottom;
}
return directions;
}
bool AxisY::HasDynamicToolbar() const {
return GetCompositionLengthWithoutDynamicToolbar() != ParentLayerCoord(0);
}
SideBits AxisY::ScrollableDirectionsWithDynamicToolbar(
const ScreenMargin& aFixedLayerMargins) const {
MOZ_ASSERT(mAsyncPanZoomController->IsRootContent());
SideBits directions = ScrollableDirections();
if (HasDynamicToolbar()) {
ParentLayerCoord toolbarHeight =
GetCompositionLength() - GetCompositionLengthWithoutDynamicToolbar();
ParentLayerMargin fixedLayerMargins = ViewAs<ParentLayerPixel>(
aFixedLayerMargins, PixelCastJustification::ScreenIsParentLayerForRoot);
if (!mAsyncPanZoomController->IsZero(fixedLayerMargins.bottom)) {
directions |= SideBits::eTop;
}
if (mAsyncPanZoomController->FuzzyGreater(
fixedLayerMargins.bottom + toolbarHeight, 0)) {
directions |= SideBits::eBottom;
}
}
return directions;
}
bool AxisY::CanVerticalScrollWithDynamicToolbar() const {
return !HasDynamicToolbar()
? CanScroll()
: mAsyncPanZoomController->FuzzyGreater(
GetPageLength(),
GetCompositionLengthWithoutDynamicToolbar());
}
OverscrollBehavior AxisY::GetOverscrollBehavior() const {
return GetScrollMetadata().GetOverscrollBehavior().mBehaviorY;
}
ParentLayerCoord AxisY::GetCompositionLengthWithoutDynamicToolbar() const {
return GetFrameMetrics().GetCompositionSizeWithoutDynamicToolbar().Height();
}
} // namespace layers
} // namespace mozilla