tor-browser

WheelEvent.cpp (7287B)

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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 file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "WheelEvent.h"

#include "mozilla/MouseEvents.h"
#include "mozilla/dom/MouseEventBinding.h"

namespace mozilla::dom {

WheelEvent::WheelEvent(EventTarget* aOwner, nsPresContext* aPresContext,
                      WidgetWheelEvent* aWheelEvent)
   : MouseEvent(aOwner, aPresContext,
                aWheelEvent
                    ? aWheelEvent
                    : new WidgetWheelEvent(false, eVoidEvent, nullptr)),
     mAppUnitsPerDevPixel(0) {
 if (aWheelEvent) {
   mEventIsInternal = false;
   // If the delta mode is pixel, the WidgetWheelEvent's delta values are in
   // device pixels.  However, JS contents need the delta values in CSS pixels.
   // We should store the value of mAppUnitsPerDevPixel here because
   // it might be changed by changing zoom or something.
   if (aWheelEvent->mDeltaMode == WheelEvent_Binding::DOM_DELTA_PIXEL) {
     mAppUnitsPerDevPixel = aPresContext->AppUnitsPerDevPixel();
   }
 } else {
   mEventIsInternal = true;
   mEvent->mRefPoint = LayoutDeviceIntPoint(0, 0);
   mEvent->AsWheelEvent()->mInputSource =
       MouseEvent_Binding::MOZ_SOURCE_UNKNOWN;
 }
}

void WheelEvent::InitWheelEventInternal(
   const nsAString& aType, bool aCanBubble, bool aCancelable,
   nsGlobalWindowInner* aView, int32_t aDetail, double aScreenX,
   double aScreenY, double aClientX, double aClientY, uint16_t aButton,
   EventTarget* aRelatedTarget, const nsAString& aModifiersList,
   double aDeltaX, double aDeltaY, double aDeltaZ, uint32_t aDeltaMode) {
 NS_ENSURE_TRUE_VOID(!mEvent->mFlags.mIsBeingDispatched);

 MouseEvent::InitMouseEventInternal(
     aType, aCanBubble, aCancelable, aView, aDetail, aScreenX, aScreenY,
     aClientX, aClientY, aButton, aRelatedTarget, aModifiersList);

 WidgetWheelEvent* wheelEvent = mEvent->AsWheelEvent();
 // When specified by the caller (for JS-created events), don't mess with the
 // delta mode.
 wheelEvent->mDeltaModeCheckingState =
     WidgetWheelEvent::DeltaModeCheckingState::Checked;
 wheelEvent->mDeltaX = aDeltaX;
 wheelEvent->mDeltaY = aDeltaY;
 wheelEvent->mDeltaZ = aDeltaZ;
 wheelEvent->mDeltaMode = aDeltaMode;
 wheelEvent->mAllowToOverrideSystemScrollSpeed = false;
}

int32_t WheelEvent::WheelDeltaX(CallerType aCallerType) {
 WidgetWheelEvent* ev = mEvent->AsWheelEvent();
 if (ev->mWheelTicksX != 0.0) {
   return int32_t(-ev->mWheelTicksX * kNativeTicksToWheelDelta);
 }
 if (IsTrusted()) {
   // We always return pixels regardless of the checking-state.
   double pixelDelta =
       ev->mDeltaMode == WheelEvent_Binding::DOM_DELTA_PIXEL
           ? CSSCoord(DevToCssPixels(ev->OverriddenDeltaX()))
           : ev->OverriddenDeltaX() *
                 CSSPixel::FromAppUnits(ev->mScrollAmount.width).Rounded();
   return int32_t(-std::round(pixelDelta * kTrustedDeltaToWheelDelta));
 }
 return int32_t(-std::round(DeltaX(aCallerType)));  // This matches Safari.
}

int32_t WheelEvent::WheelDeltaY(CallerType aCallerType) {
 WidgetWheelEvent* ev = mEvent->AsWheelEvent();
 if (ev->mWheelTicksY != 0.0) {
   return int32_t(-ev->mWheelTicksY * kNativeTicksToWheelDelta);
 }

 if (IsTrusted()) {
   double pixelDelta =
       ev->mDeltaMode == WheelEvent_Binding::DOM_DELTA_PIXEL
           ? CSSCoord(DevToCssPixels(ev->OverriddenDeltaY()))
           : ev->OverriddenDeltaY() *
                 CSSPixel::FromAppUnits(ev->mScrollAmount.height).Rounded();
   return int32_t(-std::round(pixelDelta * kTrustedDeltaToWheelDelta));
 }
 return int32_t(-std::round(DeltaY(aCallerType)));  // This matches Safari.
}

double WheelEvent::ToWebExposedDelta(WidgetWheelEvent& aWidgetEvent,
                                    double aDelta, nscoord aLineOrPageAmount,
                                    CallerType aCallerType) {
 using DeltaModeCheckingState = WidgetWheelEvent::DeltaModeCheckingState;
 if (aCallerType != CallerType::System) {
   if (aWidgetEvent.mDeltaModeCheckingState ==
       DeltaModeCheckingState::Unknown) {
     aWidgetEvent.mDeltaModeCheckingState = DeltaModeCheckingState::Unchecked;
   }
   if (aWidgetEvent.mDeltaModeCheckingState ==
           DeltaModeCheckingState::Unchecked &&
       aWidgetEvent.mDeltaMode == WheelEvent_Binding::DOM_DELTA_LINE) {
     return aDelta * CSSPixel::FromAppUnits(aLineOrPageAmount).Rounded();
   }
 }
 return DevToCssPixels(aDelta);
}

double WheelEvent::DeltaX(CallerType aCallerType) {
 WidgetWheelEvent* ev = mEvent->AsWheelEvent();
 return ToWebExposedDelta(*ev, ev->OverriddenDeltaX(), ev->mScrollAmount.width,
                          aCallerType);
}

double WheelEvent::DeltaY(CallerType aCallerType) {
 WidgetWheelEvent* ev = mEvent->AsWheelEvent();
 return ToWebExposedDelta(*ev, ev->OverriddenDeltaY(),
                          ev->mScrollAmount.height, aCallerType);
}

double WheelEvent::DeltaZ(CallerType aCallerType) {
 WidgetWheelEvent* ev = mEvent->AsWheelEvent();
 // XXX Unclear what scroll amount we should use for deltaZ...
 auto amount = std::max(ev->mScrollAmount.width, ev->mScrollAmount.height);
 return ToWebExposedDelta(*ev, ev->mDeltaZ, amount, aCallerType);
}

uint32_t WheelEvent::DeltaMode(CallerType aCallerType) {
 using DeltaModeCheckingState = WidgetWheelEvent::DeltaModeCheckingState;

 WidgetWheelEvent* ev = mEvent->AsWheelEvent();
 uint32_t mode = ev->mDeltaMode;
 if (aCallerType != CallerType::System) {
   if (ev->mDeltaModeCheckingState == DeltaModeCheckingState::Unknown) {
     ev->mDeltaModeCheckingState = DeltaModeCheckingState::Checked;
   } else if (ev->mDeltaModeCheckingState ==
                  DeltaModeCheckingState::Unchecked &&
              mode == WheelEvent_Binding::DOM_DELTA_LINE) {
     return WheelEvent_Binding::DOM_DELTA_PIXEL;
   }
 }

 return mode;
}

already_AddRefed<WheelEvent> WheelEvent::Constructor(
   const GlobalObject& aGlobal, const nsAString& aType,
   const WheelEventInit& aParam) {
 nsCOMPtr<EventTarget> t = do_QueryInterface(aGlobal.GetAsSupports());
 RefPtr<WheelEvent> e = new WheelEvent(t, nullptr, nullptr);
 bool trusted = e->Init(t);
 e->InitWheelEventInternal(
     aType, aParam.mBubbles, aParam.mCancelable, aParam.mView, aParam.mDetail,
     aParam.mScreenX, aParam.mScreenY, aParam.mClientX, aParam.mClientY,
     aParam.mButton, aParam.mRelatedTarget, u""_ns, aParam.mDeltaX,
     aParam.mDeltaY, aParam.mDeltaZ, aParam.mDeltaMode);
 e->InitializeExtraMouseEventDictionaryMembers(aParam);
 e->SetTrusted(trusted);
 e->SetComposed(aParam.mComposed);
 return e.forget();
}

}  // namespace mozilla::dom

using namespace mozilla;
using namespace mozilla::dom;

already_AddRefed<WheelEvent> NS_NewDOMWheelEvent(EventTarget* aOwner,
                                                nsPresContext* aPresContext,
                                                WidgetWheelEvent* aEvent) {
 RefPtr<WheelEvent> it = new WheelEvent(aOwner, aPresContext, aEvent);
 return it.forget();
}