1 files changed, 82 insertions, 0 deletions
diff --git a/dom/events/WheelEvent.h b/dom/events/WheelEvent.h
new file mode 100644
index 0000000000..c69764bd57
--- /dev/null
+++ b/dom/events/WheelEvent.h
@@ -0,0 +1,82 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_WheelEvent_h_
+#define mozilla_dom_WheelEvent_h_
+
+#include "mozilla/dom/MouseEvent.h"
+#include "mozilla/dom/WheelEventBinding.h"
+#include "mozilla/EventForwards.h"
+
+namespace mozilla::dom {
+
+class WheelEvent : public MouseEvent {
+ public:
+  WheelEvent(EventTarget* aOwner, nsPresContext* aPresContext,
+             WidgetWheelEvent* aWheelEvent);
+
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(WheelEvent, MouseEvent)
+
+  static already_AddRefed<WheelEvent> Constructor(const GlobalObject& aGlobal,
+                                                  const nsAString& aType,
+                                                  const WheelEventInit& aParam);
+
+  virtual JSObject* WrapObjectInternal(
+      JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override {
+    return WheelEvent_Binding::Wrap(aCx, this, aGivenProto);
+  }
+
+  double DevToCssPixels(double aDevPxValue) const {
+    if (!mAppUnitsPerDevPixel) {
+      return aDevPxValue;
+    }
+    return aDevPxValue * mAppUnitsPerDevPixel / AppUnitsPerCSSPixel();
+  }
+
+  // NOTE: DeltaX(), DeltaY() and DeltaZ() return CSS pixels when deltaMode is
+  //       DOM_DELTA_PIXEL. (The internal event's delta values are device pixels
+  //       if it's dispatched by widget)
+  double DeltaX(CallerType);
+  double DeltaY(CallerType);
+  double DeltaZ(CallerType);
+  uint32_t DeltaMode(CallerType);
+
+  int32_t WheelDelta(CallerType aCallerType) {
+    int32_t y = WheelDeltaY(aCallerType);
+    return y ? y : WheelDeltaX(aCallerType);
+  }
+
+  static constexpr int32_t kNativeTicksToWheelDelta = 120;
+  static constexpr double kTrustedDeltaToWheelDelta = 3.0;
+
+  int32_t WheelDeltaX(CallerType);
+  int32_t WheelDeltaY(CallerType);
+
+  void InitWheelEvent(const nsAString& aType, bool aCanBubble, bool aCancelable,
+                      nsGlobalWindowInner* aView, int32_t aDetail,
+                      int32_t aScreenX, int32_t aScreenY, int32_t aClientX,
+                      int32_t aClientY, uint16_t aButton,
+                      EventTarget* aRelatedTarget,
+                      const nsAString& aModifiersList, double aDeltaX,
+                      double aDeltaY, double aDeltaZ, uint32_t aDeltaMode);
+
+ protected:
+  ~WheelEvent() = default;
+
+  double ToWebExposedDelta(WidgetWheelEvent&, double aDelta,
+                           nscoord aLineOrPageAmount, CallerType);
+
+ private:
+  int32_t mAppUnitsPerDevPixel;
+};
+
+}  // namespace mozilla::dom
+
+already_AddRefed<mozilla::dom::WheelEvent> NS_NewDOMWheelEvent(
+    mozilla::dom::EventTarget* aOwner, nsPresContext* aPresContext,
+    mozilla::WidgetWheelEvent* aEvent);
+
+#endif  // mozilla_dom_WheelEvent_h_