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Diffstat (limited to 'dom/events/WheelHandlingHelper.cpp')
| -rw-r--r-- | dom/events/WheelHandlingHelper.cpp | 872 |
1 files changed, 872 insertions, 0 deletions
diff --git a/dom/events/WheelHandlingHelper.cpp b/dom/events/WheelHandlingHelper.cpp new file mode 100644 index 0000000000..3b5653c50e --- /dev/null +++ b/dom/events/WheelHandlingHelper.cpp @@ -0,0 +1,872 @@ +/* -*- 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 "WheelHandlingHelper.h" + +#include <utility> // for std::swap + +#include "mozilla/EventDispatcher.h" +#include "mozilla/EventStateManager.h" +#include "mozilla/MouseEvents.h" +#include "mozilla/Preferences.h" +#include "mozilla/PresShell.h" +#include "mozilla/StaticPrefs_mousewheel.h" +#include "mozilla/StaticPrefs_test.h" +#include "mozilla/TextControlElement.h" +#include "mozilla/dom/WheelEventBinding.h" +#include "nsCOMPtr.h" +#include "nsContentUtils.h" +#include "nsIContent.h" +#include "nsIContentInlines.h" +#include "mozilla/dom/Document.h" +#include "DocumentInlines.h" // for Document and HTMLBodyElement +#include "nsIScrollableFrame.h" +#include "nsITimer.h" +#include "nsPresContext.h" +#include "prtime.h" +#include "Units.h" +#include "ScrollAnimationPhysics.h" + +namespace mozilla { + +/******************************************************************/ +/* mozilla::DeltaValues */ +/******************************************************************/ + +DeltaValues::DeltaValues(WidgetWheelEvent* aEvent) + : deltaX(aEvent->mDeltaX), deltaY(aEvent->mDeltaY) {} + +/******************************************************************/ +/* mozilla::WheelHandlingUtils */ +/******************************************************************/ + +/* static */ +bool WheelHandlingUtils::CanScrollInRange(nscoord aMin, nscoord aValue, + nscoord aMax, double aDirection) { + return aDirection > 0.0 ? aValue < static_cast<double>(aMax) + : static_cast<double>(aMin) < aValue; +} + +/* static */ +bool WheelHandlingUtils::CanScrollOn(nsIFrame* aFrame, double aDirectionX, + double aDirectionY) { + nsIScrollableFrame* scrollableFrame = do_QueryFrame(aFrame); + if (!scrollableFrame) { + return false; + } + return CanScrollOn(scrollableFrame, aDirectionX, aDirectionY); +} + +/* static */ +bool WheelHandlingUtils::CanScrollOn(nsIScrollableFrame* aScrollFrame, + double aDirectionX, double aDirectionY) { + MOZ_ASSERT(aScrollFrame); + NS_ASSERTION(aDirectionX || aDirectionY, + "One of the delta values must be non-zero at least"); + + nsPoint scrollPt = aScrollFrame->GetVisualViewportOffset(); + nsRect scrollRange = aScrollFrame->GetScrollRangeForUserInputEvents(); + layers::ScrollDirections directions = + aScrollFrame->GetAvailableScrollingDirectionsForUserInputEvents(); + + return ((aDirectionX != 0.0) && + (directions.contains(layers::ScrollDirection::eHorizontal)) && + CanScrollInRange(scrollRange.x, scrollPt.x, scrollRange.XMost(), + aDirectionX)) || + ((aDirectionY != 0.0) && + (directions.contains(layers::ScrollDirection::eVertical)) && + CanScrollInRange(scrollRange.y, scrollPt.y, scrollRange.YMost(), + aDirectionY)); +} + +/*static*/ Maybe<layers::ScrollDirection> +WheelHandlingUtils::GetDisregardedWheelScrollDirection(const nsIFrame* aFrame) { + nsIContent* content = aFrame->GetContent(); + if (!content) { + return Nothing(); + } + TextControlElement* textControlElement = TextControlElement::FromNodeOrNull( + content->IsInNativeAnonymousSubtree() + ? content->GetClosestNativeAnonymousSubtreeRootParentOrHost() + : content); + if (!textControlElement || !textControlElement->IsSingleLineTextControl()) { + return Nothing(); + } + // Disregard scroll in the block-flow direction by mouse wheel on a + // single-line text control. For instance, in tranditional Chinese writing + // system, a single-line text control cannot be scrolled horizontally with + // mouse wheel even if they overflow at the right and left edges; Whereas in + // latin-based writing system, a single-line text control cannot be scrolled + // vertically with mouse wheel even if they overflow at the top and bottom + // edges + return Some(aFrame->GetWritingMode().IsVertical() + ? layers::ScrollDirection::eHorizontal + : layers::ScrollDirection::eVertical); +} + +/******************************************************************/ +/* mozilla::WheelTransaction */ +/******************************************************************/ + +AutoWeakFrame WheelTransaction::sScrollTargetFrame(nullptr); +AutoWeakFrame WheelTransaction::sEventTargetFrame(nullptr); +bool WheelTransaction::sHandledByApz(false); +uint32_t WheelTransaction::sTime = 0; +uint32_t WheelTransaction::sMouseMoved = 0; +nsITimer* WheelTransaction::sTimer = nullptr; +int32_t WheelTransaction::sScrollSeriesCounter = 0; +bool WheelTransaction::sOwnScrollbars = false; + +/* static */ +bool WheelTransaction::OutOfTime(uint32_t aBaseTime, uint32_t aThreshold) { + uint32_t now = PR_IntervalToMilliseconds(PR_IntervalNow()); + return (now - aBaseTime > aThreshold); +} + +/* static */ +void WheelTransaction::OwnScrollbars(bool aOwn) { sOwnScrollbars = aOwn; } + +/* static */ +void WheelTransaction::BeginTransaction(nsIFrame* aScrollTargetFrame, + nsIFrame* aEventTargetFrame, + const WidgetWheelEvent* aEvent) { + NS_ASSERTION(!sScrollTargetFrame && !sEventTargetFrame, + "previous transaction is not finished!"); + MOZ_ASSERT(aEvent->mMessage == eWheel, + "Transaction must be started with a wheel event"); + + ScrollbarsForWheel::OwnWheelTransaction(false); + sScrollTargetFrame = aScrollTargetFrame; + + // Only set the static event target if wheel event groups are enabled. + if (StaticPrefs::dom_event_wheel_event_groups_enabled()) { + // Set a static event target for the wheel transaction. This will be used + // to override the event target frame when computing the event target from + // input coordinates. When this preference is not set or there is no stored + // event target for the current wheel transaction, the event target will + // not be overridden by the current wheel transaction, but will be computed + // from the input coordinates. + sEventTargetFrame = aEventTargetFrame; + // If the wheel events will be handled by APZ, set a flag here. We can use + // this later to determine if we need to scroll snap at the end of the + // wheel operation. + sHandledByApz = aEvent->mFlags.mHandledByAPZ; + } + + sScrollSeriesCounter = 0; + if (!UpdateTransaction(aEvent)) { + NS_ERROR("BeginTransaction is called even cannot scroll the frame"); + EndTransaction(); + } +} + +/* static */ +bool WheelTransaction::UpdateTransaction(const WidgetWheelEvent* aEvent) { + nsIFrame* scrollToFrame = GetScrollTargetFrame(); + nsIScrollableFrame* scrollableFrame = scrollToFrame->GetScrollTargetFrame(); + if (scrollableFrame) { + scrollToFrame = do_QueryFrame(scrollableFrame); + } + + if (!WheelHandlingUtils::CanScrollOn(scrollToFrame, aEvent->mDeltaX, + aEvent->mDeltaY)) { + OnFailToScrollTarget(); + // We should not modify the transaction state when the view will not be + // scrolled actually. + return false; + } + + SetTimeout(); + + if (sScrollSeriesCounter != 0 && + OutOfTime(sTime, StaticPrefs::mousewheel_scroll_series_timeout())) { + sScrollSeriesCounter = 0; + } + sScrollSeriesCounter++; + + // We should use current time instead of WidgetEvent.time. + // 1. Some events doesn't have the correct creation time. + // 2. If the computer runs slowly by other processes eating the CPU resource, + // the event creation time doesn't keep real time. + sTime = PR_IntervalToMilliseconds(PR_IntervalNow()); + sMouseMoved = 0; + return true; +} + +/* static */ +void WheelTransaction::MayEndTransaction() { + if (!sOwnScrollbars && ScrollbarsForWheel::IsActive()) { + ScrollbarsForWheel::OwnWheelTransaction(true); + } else { + EndTransaction(); + } +} + +/* static */ +void WheelTransaction::EndTransaction() { + if (sTimer) { + sTimer->Cancel(); + } + sScrollTargetFrame = nullptr; + sEventTargetFrame = nullptr; + sScrollSeriesCounter = 0; + sHandledByApz = false; + if (sOwnScrollbars) { + sOwnScrollbars = false; + ScrollbarsForWheel::OwnWheelTransaction(false); + ScrollbarsForWheel::Inactivate(); + } +} + +/* static */ +bool WheelTransaction::WillHandleDefaultAction( + WidgetWheelEvent* aWheelEvent, AutoWeakFrame& aScrollTargetWeakFrame, + AutoWeakFrame& aEventTargetWeakFrame) { + nsIFrame* lastTargetFrame = GetScrollTargetFrame(); + if (!lastTargetFrame) { + BeginTransaction(aScrollTargetWeakFrame.GetFrame(), + aEventTargetWeakFrame.GetFrame(), aWheelEvent); + } else if (lastTargetFrame != aScrollTargetWeakFrame.GetFrame()) { + EndTransaction(); + BeginTransaction(aScrollTargetWeakFrame.GetFrame(), + aEventTargetWeakFrame.GetFrame(), aWheelEvent); + } else { + UpdateTransaction(aWheelEvent); + } + + // When the wheel event will not be handled with any frames, + // UpdateTransaction() fires MozMouseScrollFailed event which is for + // automated testing. In the event handler, the target frame might be + // destroyed. Then, the caller shouldn't try to handle the default action. + if (!aScrollTargetWeakFrame.IsAlive()) { + EndTransaction(); + return false; + } + + return true; +} + +/* static */ +void WheelTransaction::OnEvent(WidgetEvent* aEvent) { + if (!sScrollTargetFrame) { + return; + } + + if (OutOfTime(sTime, StaticPrefs::mousewheel_transaction_timeout())) { + // Even if the scroll event which is handled after timeout, but onTimeout + // was not fired by timer, then the scroll event will scroll old frame, + // therefore, we should call OnTimeout here and ensure to finish the old + // transaction. + OnTimeout(nullptr, nullptr); + return; + } + + switch (aEvent->mMessage) { + case eWheel: + if (sMouseMoved != 0 && + OutOfTime(sMouseMoved, + StaticPrefs::mousewheel_transaction_ignoremovedelay())) { + // Terminate the current mousewheel transaction if the mouse moved more + // than ignoremovedelay milliseconds ago + EndTransaction(); + } + return; + case eMouseMove: + case eDragOver: { + WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent(); + if (mouseEvent->IsReal()) { + // If the cursor is moving to be outside the frame, + // terminate the scrollwheel transaction. + LayoutDeviceIntPoint pt = GetScreenPoint(mouseEvent); + auto r = LayoutDeviceIntRect::FromAppUnitsToNearest( + sScrollTargetFrame->GetScreenRectInAppUnits(), + sScrollTargetFrame->PresContext()->AppUnitsPerDevPixel()); + if (!r.Contains(pt)) { + EndTransaction(); + return; + } + + // For mouse move events where the wheel transaction is still valid, the + // stored event target should be reset. + sEventTargetFrame = nullptr; + + // If the cursor is moving inside the frame, and it is less than + // ignoremovedelay milliseconds since the last scroll operation, ignore + // the mouse move; otherwise, record the current mouse move time to be + // checked later + if (!sMouseMoved && + OutOfTime(sTime, + StaticPrefs::mousewheel_transaction_ignoremovedelay())) { + sMouseMoved = PR_IntervalToMilliseconds(PR_IntervalNow()); + } + } + return; + } + case eKeyPress: + case eKeyUp: + case eKeyDown: + case eMouseUp: + case eMouseDown: + case eMouseDoubleClick: + case eMouseAuxClick: + case eMouseClick: + case eContextMenu: + case eDrop: + EndTransaction(); + return; + default: + break; + } +} + +/* static */ +void WheelTransaction::OnRemoveElement(nsIContent* aContent) { + // If dom.event.wheel-event-groups.enabled is not set or we have no current + // wheel event transaction there is no internal state to be updated. + if (!sEventTargetFrame) { + return; + } + + if (sEventTargetFrame->GetContent() == aContent) { + // Only invalidate the wheel transaction event target frame when the + // remove target is the event target of the wheel event group. The + // scroll target frame of the wheel event group may still be valid. + // + // With the stored event target unset, the target for any following + // events will be the frame found using the input coordinates. + sEventTargetFrame = nullptr; + } +} + +/* static */ +void WheelTransaction::Shutdown() { NS_IF_RELEASE(sTimer); } + +/* static */ +void WheelTransaction::OnFailToScrollTarget() { + MOZ_ASSERT(sScrollTargetFrame, "We don't have mouse scrolling transaction"); + + if (StaticPrefs::test_mousescroll()) { + // This event is used for automated tests, see bug 442774. + nsContentUtils::DispatchEventOnlyToChrome( + sScrollTargetFrame->GetContent()->OwnerDoc(), + sScrollTargetFrame->GetContent(), u"MozMouseScrollFailed"_ns, + CanBubble::eYes, Cancelable::eYes); + } + // The target frame might be destroyed in the event handler, at that time, + // we need to finish the current transaction + if (!sScrollTargetFrame) { + EndTransaction(); + } +} + +/* static */ +void WheelTransaction::OnTimeout(nsITimer* aTimer, void* aClosure) { + if (!sScrollTargetFrame) { + // The transaction target was destroyed already + EndTransaction(); + return; + } + // Store the sScrollTargetFrame, the variable becomes null in EndTransaction. + nsIFrame* frame = sScrollTargetFrame; + // We need to finish current transaction before DOM event firing. Because + // the next DOM event might create strange situation for us. + MayEndTransaction(); + + if (StaticPrefs::test_mousescroll()) { + // This event is used for automated tests, see bug 442774. + nsContentUtils::DispatchEventOnlyToChrome( + frame->GetContent()->OwnerDoc(), frame->GetContent(), + u"MozMouseScrollTransactionTimeout"_ns, CanBubble::eYes, + Cancelable::eYes); + } +} + +/* static */ +void WheelTransaction::SetTimeout() { + if (!sTimer) { + sTimer = NS_NewTimer().take(); + if (!sTimer) { + return; + } + } + sTimer->Cancel(); + DebugOnly<nsresult> rv = sTimer->InitWithNamedFuncCallback( + OnTimeout, nullptr, StaticPrefs::mousewheel_transaction_timeout(), + nsITimer::TYPE_ONE_SHOT, "WheelTransaction::SetTimeout"); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "nsITimer::InitWithFuncCallback failed"); +} + +/* static */ +LayoutDeviceIntPoint WheelTransaction::GetScreenPoint(WidgetGUIEvent* aEvent) { + NS_ASSERTION(aEvent, "aEvent is null"); + NS_ASSERTION(aEvent->mWidget, "aEvent-mWidget is null"); + return aEvent->mRefPoint + aEvent->mWidget->WidgetToScreenOffset(); +} + +/* static */ +DeltaValues WheelTransaction::AccelerateWheelDelta(WidgetWheelEvent* aEvent) { + DeltaValues result = OverrideSystemScrollSpeed(aEvent); + + // Don't accelerate the delta values if the event isn't line scrolling. + if (aEvent->mDeltaMode != dom::WheelEvent_Binding::DOM_DELTA_LINE) { + return result; + } + + // Accelerate by the sScrollSeriesCounter + int32_t start = StaticPrefs::mousewheel_acceleration_start(); + if (start >= 0 && sScrollSeriesCounter >= start) { + int32_t factor = StaticPrefs::mousewheel_acceleration_factor(); + if (factor > 0) { + result.deltaX = ComputeAcceleratedWheelDelta(result.deltaX, factor); + result.deltaY = ComputeAcceleratedWheelDelta(result.deltaY, factor); + } + } + + return result; +} + +/* static */ +double WheelTransaction::ComputeAcceleratedWheelDelta(double aDelta, + int32_t aFactor) { + return mozilla::ComputeAcceleratedWheelDelta(aDelta, sScrollSeriesCounter, + aFactor); +} + +/* static */ +DeltaValues WheelTransaction::OverrideSystemScrollSpeed( + WidgetWheelEvent* aEvent) { + MOZ_ASSERT(sScrollTargetFrame, "We don't have mouse scrolling transaction"); + + // If the event doesn't scroll to both X and Y, we don't need to do anything + // here. + if (!aEvent->mDeltaX && !aEvent->mDeltaY) { + return DeltaValues(aEvent); + } + + return DeltaValues(aEvent->OverriddenDeltaX(), aEvent->OverriddenDeltaY()); +} + +/******************************************************************/ +/* mozilla::ScrollbarsForWheel */ +/******************************************************************/ + +const DeltaValues ScrollbarsForWheel::directions[kNumberOfTargets] = { + DeltaValues(-1, 0), DeltaValues(+1, 0), DeltaValues(0, -1), + DeltaValues(0, +1)}; + +AutoWeakFrame ScrollbarsForWheel::sActiveOwner = nullptr; +AutoWeakFrame ScrollbarsForWheel::sActivatedScrollTargets[kNumberOfTargets] = { + nullptr, nullptr, nullptr, nullptr}; + +bool ScrollbarsForWheel::sHadWheelStart = false; +bool ScrollbarsForWheel::sOwnWheelTransaction = false; + +/* static */ +void ScrollbarsForWheel::PrepareToScrollText(EventStateManager* aESM, + nsIFrame* aTargetFrame, + WidgetWheelEvent* aEvent) { + if (aEvent->mMessage == eWheelOperationStart) { + WheelTransaction::OwnScrollbars(false); + if (!IsActive()) { + TemporarilyActivateAllPossibleScrollTargets(aESM, aTargetFrame, aEvent); + sHadWheelStart = true; + } + } else { + DeactivateAllTemporarilyActivatedScrollTargets(); + } +} + +/* static */ +void ScrollbarsForWheel::SetActiveScrollTarget( + nsIScrollableFrame* aScrollTarget) { + if (!sHadWheelStart) { + return; + } + nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(aScrollTarget); + if (!scrollbarMediator) { + return; + } + sHadWheelStart = false; + sActiveOwner = do_QueryFrame(aScrollTarget); + scrollbarMediator->ScrollbarActivityStarted(); +} + +/* static */ +void ScrollbarsForWheel::MayInactivate() { + if (!sOwnWheelTransaction && WheelTransaction::GetScrollTargetFrame()) { + WheelTransaction::OwnScrollbars(true); + } else { + Inactivate(); + } +} + +/* static */ +void ScrollbarsForWheel::Inactivate() { + nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(sActiveOwner); + if (scrollbarMediator) { + scrollbarMediator->ScrollbarActivityStopped(); + } + sActiveOwner = nullptr; + DeactivateAllTemporarilyActivatedScrollTargets(); + if (sOwnWheelTransaction) { + sOwnWheelTransaction = false; + WheelTransaction::OwnScrollbars(false); + WheelTransaction::EndTransaction(); + } +} + +/* static */ +bool ScrollbarsForWheel::IsActive() { + if (sActiveOwner) { + return true; + } + for (size_t i = 0; i < kNumberOfTargets; ++i) { + if (sActivatedScrollTargets[i]) { + return true; + } + } + return false; +} + +/* static */ +void ScrollbarsForWheel::OwnWheelTransaction(bool aOwn) { + sOwnWheelTransaction = aOwn; +} + +/* static */ +void ScrollbarsForWheel::TemporarilyActivateAllPossibleScrollTargets( + EventStateManager* aESM, nsIFrame* aTargetFrame, WidgetWheelEvent* aEvent) { + for (size_t i = 0; i < kNumberOfTargets; i++) { + const DeltaValues* dir = &directions[i]; + AutoWeakFrame* scrollTarget = &sActivatedScrollTargets[i]; + MOZ_ASSERT(!*scrollTarget, "scroll target still temporarily activated!"); + nsIScrollableFrame* target = do_QueryFrame(aESM->ComputeScrollTarget( + aTargetFrame, dir->deltaX, dir->deltaY, aEvent, + EventStateManager::COMPUTE_DEFAULT_ACTION_TARGET)); + nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(target); + if (scrollbarMediator) { + nsIFrame* targetFrame = do_QueryFrame(target); + *scrollTarget = targetFrame; + scrollbarMediator->ScrollbarActivityStarted(); + } + } +} + +/* static */ +void ScrollbarsForWheel::DeactivateAllTemporarilyActivatedScrollTargets() { + for (size_t i = 0; i < kNumberOfTargets; i++) { + AutoWeakFrame* scrollTarget = &sActivatedScrollTargets[i]; + if (*scrollTarget) { + nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(*scrollTarget); + if (scrollbarMediator) { + scrollbarMediator->ScrollbarActivityStopped(); + } + *scrollTarget = nullptr; + } + } +} + +/******************************************************************/ +/* mozilla::WheelDeltaHorizontalizer */ +/******************************************************************/ + +void WheelDeltaHorizontalizer::Horizontalize() { + MOZ_ASSERT(!mWheelEvent.mDeltaValuesHorizontalizedForDefaultHandler, + "Wheel delta values in one wheel scroll event are being adjusted " + "a second time"); + + // Log the old values. + mOldDeltaX = mWheelEvent.mDeltaX; + mOldDeltaZ = mWheelEvent.mDeltaZ; + mOldOverflowDeltaX = mWheelEvent.mOverflowDeltaX; + mOldLineOrPageDeltaX = mWheelEvent.mLineOrPageDeltaX; + + // Move deltaY values to deltaX and set both deltaY and deltaZ to 0. + mWheelEvent.mDeltaX = mWheelEvent.mDeltaY; + mWheelEvent.mDeltaY = 0.0; + mWheelEvent.mDeltaZ = 0.0; + mWheelEvent.mOverflowDeltaX = mWheelEvent.mOverflowDeltaY; + mWheelEvent.mOverflowDeltaY = 0.0; + mWheelEvent.mLineOrPageDeltaX = mWheelEvent.mLineOrPageDeltaY; + mWheelEvent.mLineOrPageDeltaY = 0; + + // Mark it horizontalized in order to restore the delta values when this + // instance is being destroyed. + mWheelEvent.mDeltaValuesHorizontalizedForDefaultHandler = true; + mHorizontalized = true; +} + +void WheelDeltaHorizontalizer::CancelHorizontalization() { + // Restore the horizontalized delta. + if (mHorizontalized && + mWheelEvent.mDeltaValuesHorizontalizedForDefaultHandler) { + mWheelEvent.mDeltaY = mWheelEvent.mDeltaX; + mWheelEvent.mDeltaX = mOldDeltaX; + mWheelEvent.mDeltaZ = mOldDeltaZ; + mWheelEvent.mOverflowDeltaY = mWheelEvent.mOverflowDeltaX; + mWheelEvent.mOverflowDeltaX = mOldOverflowDeltaX; + mWheelEvent.mLineOrPageDeltaY = mWheelEvent.mLineOrPageDeltaX; + mWheelEvent.mLineOrPageDeltaX = mOldLineOrPageDeltaX; + mWheelEvent.mDeltaValuesHorizontalizedForDefaultHandler = false; + mHorizontalized = false; + } +} + +WheelDeltaHorizontalizer::~WheelDeltaHorizontalizer() { + CancelHorizontalization(); +} + +/******************************************************************/ +/* mozilla::AutoDirWheelDeltaAdjuster */ +/******************************************************************/ + +bool AutoDirWheelDeltaAdjuster::ShouldBeAdjusted() { + // Sometimes, this function can be called more than one time. If we have + // already checked if the scroll should be adjusted, there's no need to check + // it again. + if (mCheckedIfShouldBeAdjusted) { + return mShouldBeAdjusted; + } + mCheckedIfShouldBeAdjusted = true; + + // For an auto-dir wheel scroll, if all the following conditions are met, we + // should adjust X and Y values: + // 1. There is only one non-zero value between DeltaX and DeltaY. + // 2. There is only one direction for the target that overflows and is + // scrollable with wheel. + // 3. The direction described in Condition 1 is orthogonal to the one + // described in Condition 2. + if ((mDeltaX && mDeltaY) || (!mDeltaX && !mDeltaY)) { + return false; + } + if (mDeltaX) { + if (CanScrollAlongXAxis()) { + return false; + } + if (IsHorizontalContentRightToLeft()) { + mShouldBeAdjusted = + mDeltaX > 0 ? CanScrollUpwards() : CanScrollDownwards(); + } else { + mShouldBeAdjusted = + mDeltaX < 0 ? CanScrollUpwards() : CanScrollDownwards(); + } + return mShouldBeAdjusted; + } + MOZ_ASSERT(0 != mDeltaY); + if (CanScrollAlongYAxis()) { + return false; + } + if (IsHorizontalContentRightToLeft()) { + mShouldBeAdjusted = + mDeltaY > 0 ? CanScrollLeftwards() : CanScrollRightwards(); + } else { + mShouldBeAdjusted = + mDeltaY < 0 ? CanScrollLeftwards() : CanScrollRightwards(); + } + return mShouldBeAdjusted; +} + +void AutoDirWheelDeltaAdjuster::Adjust() { + if (!ShouldBeAdjusted()) { + return; + } + std::swap(mDeltaX, mDeltaY); + if (IsHorizontalContentRightToLeft()) { + mDeltaX *= -1; + mDeltaY *= -1; + } + mShouldBeAdjusted = false; + OnAdjusted(); +} + +/******************************************************************/ +/* mozilla::ESMAutoDirWheelDeltaAdjuster */ +/******************************************************************/ + +ESMAutoDirWheelDeltaAdjuster::ESMAutoDirWheelDeltaAdjuster( + WidgetWheelEvent& aEvent, nsIFrame& aScrollFrame, bool aHonoursRoot) + : AutoDirWheelDeltaAdjuster(aEvent.mDeltaX, aEvent.mDeltaY), + mLineOrPageDeltaX(aEvent.mLineOrPageDeltaX), + mLineOrPageDeltaY(aEvent.mLineOrPageDeltaY), + mOverflowDeltaX(aEvent.mOverflowDeltaX), + mOverflowDeltaY(aEvent.mOverflowDeltaY) { + mScrollTargetFrame = aScrollFrame.GetScrollTargetFrame(); + MOZ_ASSERT(mScrollTargetFrame); + + nsIFrame* honouredFrame = nullptr; + if (aHonoursRoot) { + // If we are going to honour root, first try to get the frame for <body> as + // the honoured root, because <body> is in preference to <html> if the + // current document is an HTML document. + dom::Document* document = aScrollFrame.PresShell()->GetDocument(); + if (document) { + dom::Element* bodyElement = document->GetBodyElement(); + if (bodyElement) { + honouredFrame = bodyElement->GetPrimaryFrame(); + } + } + + if (!honouredFrame) { + // If there is no <body> frame, fall back to the real root frame. + honouredFrame = aScrollFrame.PresShell()->GetRootScrollFrame(); + } + + if (!honouredFrame) { + // If there is no root scroll frame, fall back to the current scrolling + // frame. + honouredFrame = &aScrollFrame; + } + } else { + honouredFrame = &aScrollFrame; + } + + WritingMode writingMode = honouredFrame->GetWritingMode(); + WritingMode::BlockDir blockDir = writingMode.GetBlockDir(); + WritingMode::InlineDir inlineDir = writingMode.GetInlineDir(); + // Get whether the honoured frame's content in the horizontal direction starts + // from right to left(E.g. it's true either if "writing-mode: vertical-rl", or + // if "writing-mode: horizontal-tb; direction: rtl;" in CSS). + mIsHorizontalContentRightToLeft = + (blockDir == WritingMode::BlockDir::eBlockRL || + (blockDir == WritingMode::BlockDir::eBlockTB && + inlineDir == WritingMode::InlineDir::eInlineRTL)); +} + +void ESMAutoDirWheelDeltaAdjuster::OnAdjusted() { + // Adjust() only adjusted basic deltaX and deltaY, which are not enough for + // ESM, we should continue to adjust line-or-page and overflow values. + if (mDeltaX) { + // A vertical scroll was adjusted to be horizontal. + MOZ_ASSERT(0 == mDeltaY); + + mLineOrPageDeltaX = mLineOrPageDeltaY; + mLineOrPageDeltaY = 0; + mOverflowDeltaX = mOverflowDeltaY; + mOverflowDeltaY = 0; + } else { + // A horizontal scroll was adjusted to be vertical. + MOZ_ASSERT(0 != mDeltaY); + + mLineOrPageDeltaY = mLineOrPageDeltaX; + mLineOrPageDeltaX = 0; + mOverflowDeltaY = mOverflowDeltaX; + mOverflowDeltaX = 0; + } + if (mIsHorizontalContentRightToLeft) { + // If in RTL writing mode, reverse the side the scroll will go towards. + mLineOrPageDeltaX *= -1; + mLineOrPageDeltaY *= -1; + mOverflowDeltaX *= -1; + mOverflowDeltaY *= -1; + } +} + +bool ESMAutoDirWheelDeltaAdjuster::CanScrollAlongXAxis() const { + return mScrollTargetFrame->GetAvailableScrollingDirections().contains( + layers::ScrollDirection::eHorizontal); +} + +bool ESMAutoDirWheelDeltaAdjuster::CanScrollAlongYAxis() const { + return mScrollTargetFrame->GetAvailableScrollingDirections().contains( + layers::ScrollDirection::eVertical); +} + +bool ESMAutoDirWheelDeltaAdjuster::CanScrollUpwards() const { + nsPoint scrollPt = mScrollTargetFrame->GetScrollPosition(); + nsRect scrollRange = mScrollTargetFrame->GetScrollRange(); + return static_cast<double>(scrollRange.y) < scrollPt.y; +} + +bool ESMAutoDirWheelDeltaAdjuster::CanScrollDownwards() const { + nsPoint scrollPt = mScrollTargetFrame->GetScrollPosition(); + nsRect scrollRange = mScrollTargetFrame->GetScrollRange(); + return static_cast<double>(scrollRange.YMost()) > scrollPt.y; +} + +bool ESMAutoDirWheelDeltaAdjuster::CanScrollLeftwards() const { + nsPoint scrollPt = mScrollTargetFrame->GetScrollPosition(); + nsRect scrollRange = mScrollTargetFrame->GetScrollRange(); + return static_cast<double>(scrollRange.x) < scrollPt.x; +} + +bool ESMAutoDirWheelDeltaAdjuster::CanScrollRightwards() const { + nsPoint scrollPt = mScrollTargetFrame->GetScrollPosition(); + nsRect scrollRange = mScrollTargetFrame->GetScrollRange(); + return static_cast<double>(scrollRange.XMost()) > scrollPt.x; +} + +bool ESMAutoDirWheelDeltaAdjuster::IsHorizontalContentRightToLeft() const { + return mIsHorizontalContentRightToLeft; +} + +/******************************************************************/ +/* mozilla::ESMAutoDirWheelDeltaRestorer */ +/******************************************************************/ + +/*explicit*/ +ESMAutoDirWheelDeltaRestorer::ESMAutoDirWheelDeltaRestorer( + WidgetWheelEvent& aEvent) + : mEvent(aEvent), + mOldDeltaX(aEvent.mDeltaX), + mOldDeltaY(aEvent.mDeltaY), + mOldLineOrPageDeltaX(aEvent.mLineOrPageDeltaX), + mOldLineOrPageDeltaY(aEvent.mLineOrPageDeltaY), + mOldOverflowDeltaX(aEvent.mOverflowDeltaX), + mOldOverflowDeltaY(aEvent.mOverflowDeltaY) {} + +ESMAutoDirWheelDeltaRestorer::~ESMAutoDirWheelDeltaRestorer() { + if (mOldDeltaX == mEvent.mDeltaX || mOldDeltaY == mEvent.mDeltaY) { + // The delta of the event wasn't adjusted during the lifetime of this + // |ESMAutoDirWheelDeltaRestorer| instance. No need to restore it. + return; + } + + bool forRTL = false; + + // First, restore the basic deltaX and deltaY. + std::swap(mEvent.mDeltaX, mEvent.mDeltaY); + if (mOldDeltaX != mEvent.mDeltaX || mOldDeltaY != mEvent.mDeltaY) { + // If X and Y still don't equal to their original values after being + // swapped, then it must be because they were adjusted for RTL. + forRTL = true; + mEvent.mDeltaX *= -1; + mEvent.mDeltaY *= -1; + MOZ_ASSERT(mOldDeltaX == mEvent.mDeltaX && mOldDeltaY == mEvent.mDeltaY); + } + + if (mEvent.mDeltaX) { + // A horizontal scroll was adjusted to be vertical during the lifetime of + // this instance. + MOZ_ASSERT(0 == mEvent.mDeltaY); + + // Restore the line-or-page and overflow values to be horizontal. + mEvent.mOverflowDeltaX = mEvent.mOverflowDeltaY; + mEvent.mLineOrPageDeltaX = mEvent.mLineOrPageDeltaY; + if (forRTL) { + mEvent.mOverflowDeltaX *= -1; + mEvent.mLineOrPageDeltaX *= -1; + } + mEvent.mOverflowDeltaY = mOldOverflowDeltaY; + mEvent.mLineOrPageDeltaY = mOldLineOrPageDeltaY; + } else { + // A vertical scroll was adjusted to be horizontal during the lifetime of + // this instance. + MOZ_ASSERT(0 != mEvent.mDeltaY); + + // Restore the line-or-page and overflow values to be vertical. + mEvent.mOverflowDeltaY = mEvent.mOverflowDeltaX; + mEvent.mLineOrPageDeltaY = mEvent.mLineOrPageDeltaX; + if (forRTL) { + mEvent.mOverflowDeltaY *= -1; + mEvent.mLineOrPageDeltaY *= -1; + } + mEvent.mOverflowDeltaX = mOldOverflowDeltaX; + mEvent.mLineOrPageDeltaX = mOldLineOrPageDeltaX; + } +} + +} // namespace mozilla |