dom/events/WheelEvent.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_WheelEvent_h_
   8 #define mozilla_dom_WheelEvent_h_
   9
  10 #include "mozilla/dom/MouseEvent.h"
  11 #include "mozilla/dom/WheelEventBinding.h"
  12 #include "mozilla/EventForwards.h"
  13
  14 namespace mozilla::dom {
  15
  16 class WheelEvent : public MouseEvent {
  17  public:
  18   WheelEvent(EventTarget* aOwner, nsPresContext* aPresContext,
  19              WidgetWheelEvent* aWheelEvent);
  20
  21   NS_INLINE_DECL_REFCOUNTING_INHERITED(WheelEvent, MouseEvent)
  22
  23   static already_AddRefed<WheelEvent> Constructor(const GlobalObject& aGlobal,
  24                                                   const nsAString& aType,
  25                                                   const WheelEventInit& aParam);
  26
  27   virtual JSObject* WrapObjectInternal(
  28       JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override {
  29     return WheelEvent_Binding::Wrap(aCx, this, aGivenProto);
  30   }
  31
  32   double DevToCssPixels(double aDevPxValue) const {
  33     if (!mAppUnitsPerDevPixel) {
  34       return aDevPxValue;
  35     }
  36     return aDevPxValue * mAppUnitsPerDevPixel / AppUnitsPerCSSPixel();
  37   }
  38
  39   // NOTE: DeltaX(), DeltaY() and DeltaZ() return CSS pixels when deltaMode is
  40   //       DOM_DELTA_PIXEL. (The internal event's delta values are device pixels
  41   //       if it's dispatched by widget)
  42   double DeltaX(CallerType);
  43   double DeltaY(CallerType);
  44   double DeltaZ(CallerType);
  45   uint32_t DeltaMode(CallerType);
  46
  47   int32_t WheelDelta(CallerType aCallerType) {
  48     int32_t y = WheelDeltaY(aCallerType);
  49     return y ? y : WheelDeltaX(aCallerType);
  50   }
  51
  52   static constexpr int32_t kNativeTicksToWheelDelta = 120;
  53   static constexpr double kTrustedDeltaToWheelDelta = 3.0;
  54
  55   int32_t WheelDeltaX(CallerType);
  56   int32_t WheelDeltaY(CallerType);
  57
  58   void InitWheelEvent(const nsAString& aType, bool aCanBubble, bool aCancelable,
  59                       nsGlobalWindowInner* aView, int32_t aDetail,
  60                       int32_t aScreenX, int32_t aScreenY, int32_t aClientX,
  61                       int32_t aClientY, uint16_t aButton,
  62                       EventTarget* aRelatedTarget,
  63                       const nsAString& aModifiersList, double aDeltaX,
  64                       double aDeltaY, double aDeltaZ, uint32_t aDeltaMode);
  65
  66  protected:
  67   ~WheelEvent() = default;
  68
  69   double ToWebExposedDelta(WidgetWheelEvent&, double aDelta,
  70                            nscoord aLineOrPageAmount, CallerType);
  71
  72  private:
  73   int32_t mAppUnitsPerDevPixel;
  74 };
  75
  76 }  // namespace mozilla::dom
  77
  78 already_AddRefed<mozilla::dom::WheelEvent> NS_NewDOMWheelEvent(
  79     mozilla::dom::EventTarget* aOwner, nsPresContext* aPresContext,
  80     mozilla::WidgetWheelEvent* aEvent);
  81
  82 #endif  // mozilla_dom_WheelEvent_h_