Source/core/platform/PlatformWheelEvent.h

/*
 * Copyright (C) 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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#ifndef PlatformWheelEvent_h
#define PlatformWheelEvent_h

#include "core/platform/PlatformEvent.h"
#include "core/platform/graphics/IntPoint.h"

namespace WebCore {

    class FloatPoint;
    class FloatSize;

    // Wheel events come in two flavors:
    // The ScrollByPixelWheelEvent is a fine-grained event that specifies the precise number of pixels to scroll.  It is sent directly by MacBook touchpads on OS X,
    // and synthesized in other cases where platforms generate line-by-line scrolling events.
    // The ScrollByPageWheelEvent indicates that the wheel event should scroll an entire page.  In this case WebCore's built in paging behavior is used to page
    // up and down (you get the same behavior as if the user was clicking in a scrollbar track to page up or page down).
    enum PlatformWheelEventGranularity {
        ScrollByPageWheelEvent,
        ScrollByPixelWheelEvent,
    };

#if OS(MACOSX)
    enum PlatformWheelEventPhase {
        PlatformWheelEventPhaseNone        = 0,
        PlatformWheelEventPhaseBegan       = 1 << 0,
        PlatformWheelEventPhaseStationary  = 1 << 1,
        PlatformWheelEventPhaseChanged     = 1 << 2,
        PlatformWheelEventPhaseEnded       = 1 << 3,
        PlatformWheelEventPhaseCancelled   = 1 << 4,
        PlatformWheelEventPhaseMayBegin    = 1 << 5,
    };
#endif

    class PlatformWheelEvent : public PlatformEvent {
    public:
        PlatformWheelEvent()
            : PlatformEvent(PlatformEvent::Wheel)
            , m_deltaX(0)
            , m_deltaY(0)
            , m_wheelTicksX(0)
            , m_wheelTicksY(0)
            , m_granularity(ScrollByPixelWheelEvent)
            , m_directionInvertedFromDevice(false)
            , m_hasPreciseScrollingDeltas(false)
#if OS(MACOSX)
            , m_phase(PlatformWheelEventPhaseNone)
            , m_momentumPhase(PlatformWheelEventPhaseNone)
            , m_scrollCount(0)
            , m_unacceleratedScrollingDeltaX(0)
            , m_unacceleratedScrollingDeltaY(0)
#endif
        {
        }

        PlatformWheelEvent(IntPoint position, IntPoint globalPosition, float deltaX, float deltaY, float wheelTicksX, float wheelTicksY, PlatformWheelEventGranularity granularity, bool shiftKey, bool ctrlKey, bool altKey, bool metaKey)
            : PlatformEvent(PlatformEvent::Wheel, shiftKey, ctrlKey, altKey, metaKey, 0)
            , m_position(position)
            , m_globalPosition(globalPosition)
            , m_deltaX(deltaX)
            , m_deltaY(deltaY)
            , m_wheelTicksX(wheelTicksX)
            , m_wheelTicksY(wheelTicksY)
            , m_granularity(granularity)
            , m_directionInvertedFromDevice(false)
            , m_hasPreciseScrollingDeltas(false)
#if OS(MACOSX)
            , m_phase(PlatformWheelEventPhaseNone)
            , m_momentumPhase(PlatformWheelEventPhaseNone)
            , m_scrollCount(0)
            , m_unacceleratedScrollingDeltaX(0)
            , m_unacceleratedScrollingDeltaY(0)
#endif
        {
        }

        PlatformWheelEvent copyTurningVerticalTicksIntoHorizontalTicks() const
        {
            PlatformWheelEvent copy = *this;

            copy.m_deltaX = copy.m_deltaY;
            copy.m_deltaY = 0;
            copy.m_wheelTicksX = copy.m_wheelTicksY;
            copy.m_wheelTicksY = 0;

            return copy;
        }

        const IntPoint& position() const { return m_position; } // PlatformWindow coordinates.
        const IntPoint& globalPosition() const { return m_globalPosition; } // Screen coordinates.

        float deltaX() const { return m_deltaX; }
        float deltaY() const { return m_deltaY; }

        float wheelTicksX() const { return m_wheelTicksX; }
        float wheelTicksY() const { return m_wheelTicksY; }

        PlatformWheelEventGranularity granularity() const { return m_granularity; }

        bool directionInvertedFromDevice() const { return m_directionInvertedFromDevice; }

        bool hasPreciseScrollingDeltas() const { return m_hasPreciseScrollingDeltas; }
        void setHasPreciseScrollingDeltas(bool b) { m_hasPreciseScrollingDeltas = b; }
#if OS(MACOSX)
        PlatformWheelEventPhase phase() const { return m_phase; }
        PlatformWheelEventPhase momentumPhase() const { return m_momentumPhase; }
        unsigned scrollCount() const { return m_scrollCount; }
        float unacceleratedScrollingDeltaX() const { return m_unacceleratedScrollingDeltaX; }
        float unacceleratedScrollingDeltaY() const { return m_unacceleratedScrollingDeltaY; }
        bool useLatchedEventNode() const { return m_momentumPhase == PlatformWheelEventPhaseBegan || m_momentumPhase == PlatformWheelEventPhaseChanged; }
#else
        bool useLatchedEventNode() const { return false; }
#endif

    protected:
        IntPoint m_position;
        IntPoint m_globalPosition;
        float m_deltaX;
        float m_deltaY;
        float m_wheelTicksX;
        float m_wheelTicksY;
        PlatformWheelEventGranularity m_granularity;
        bool m_directionInvertedFromDevice;
        bool m_hasPreciseScrollingDeltas;
#if OS(MACOSX)
        PlatformWheelEventPhase m_phase;
        PlatformWheelEventPhase m_momentumPhase;
        unsigned m_scrollCount;
        float m_unacceleratedScrollingDeltaX;
        float m_unacceleratedScrollingDeltaY;
#endif
    };

} // namespace WebCore

#endif // PlatformWheelEvent_h