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 {
  15 namespace dom {
  16
  17 class WheelEvent : public MouseEvent {
  18  public:
  19   WheelEvent(EventTarget* aOwner, nsPresContext* aPresContext,
  20              WidgetWheelEvent* aWheelEvent);
  21
  22   NS_INLINE_DECL_REFCOUNTING_INHERITED(WheelEvent, MouseEvent)
  23
  24   static already_AddRefed<WheelEvent> Constructor(const GlobalObject& aGlobal,
  25                                                   const nsAString& aType,
  26                                                   const WheelEventInit& aParam);
  27
  28   virtual JSObject* WrapObjectInternal(
  29       JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override {
  30     return WheelEvent_Binding::Wrap(aCx, this, aGivenProto);
  31   }
  32
  33   double DevToCssPixels(double aDevPxValue) const {
  34     if (!mAppUnitsPerDevPixel) {
  35       return aDevPxValue;
  36     }
  37     return aDevPxValue * mAppUnitsPerDevPixel / AppUnitsPerCSSPixel();
  38   }
  39
  40   // NOTE: DeltaX(), DeltaY() and DeltaZ() return CSS pixels when deltaMode is
  41   //       DOM_DELTA_PIXEL. (The internal event's delta values are device pixels
  42   //       if it's dispatched by widget)
  43   double DeltaX(CallerType);
  44   double DeltaY(CallerType);
  45   double DeltaZ(CallerType);
  46   uint32_t DeltaMode(CallerType);
  47
  48   int32_t WheelDelta(CallerType aCallerType) {
  49     int32_t y = WheelDeltaY(aCallerType);
  50     return y ? y : WheelDeltaX(aCallerType);
  51   }
  52
  53   static constexpr int32_t kNativeTicksToWheelDelta = 120;
  54   static constexpr double kTrustedDeltaToWheelDelta = 3.0;
  55
  56   int32_t WheelDeltaX(CallerType);
  57   int32_t WheelDeltaY(CallerType);
  58
  59   void InitWheelEvent(const nsAString& aType, bool aCanBubble, bool aCancelable,
  60                       nsGlobalWindowInner* aView, int32_t aDetail,
  61                       int32_t aScreenX, int32_t aScreenY, int32_t aClientX,
  62                       int32_t aClientY, uint16_t aButton,
  63                       EventTarget* aRelatedTarget,
  64                       const nsAString& aModifiersList, double aDeltaX,
  65                       double aDeltaY, double aDeltaZ, uint32_t aDeltaMode);
  66
  67  protected:
  68   ~WheelEvent() = default;
  69
  70   double ToWebExposedDelta(WidgetWheelEvent&, double aDelta,
  71                            nscoord aLineOrPageAmount, CallerType);
  72
  73  private:
  74   int32_t mAppUnitsPerDevPixel;
  75 };
  76
  77 }  // namespace dom
  78 }  // namespace mozilla
  79
  80 already_AddRefed<mozilla::dom::WheelEvent> NS_NewDOMWheelEvent(
  81     mozilla::dom::EventTarget* aOwner, nsPresContext* aPresContext,
  82     mozilla::WidgetWheelEvent* aEvent);
  83
  84 #endif  // mozilla_dom_WheelEvent_h_