Add QQuickPointerScrollEvent as a wrapper for QWheelEvent

We'll use this for delivery of QWheelEvents to both Items and
Pointer Handlers.  Later we can perhaps use it for QScrollEvent too.

Task-number: QTBUG-68119
Change-Id: I04cbbc85fe1a86cf5fd0374d353876f7e6140b70
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

2 files changed, 110 insertions, 0 deletions

diff --git a/src/quick/items/qquickevents.cpp b/src/quick/items/qquickevents.cpp
index ece6c3f07c..fc25de38b1 100644
--- a/src/quick/items/qquickevents.cpp
+++ b/src/quick/items/qquickevents.cpp
@@ -1424,6 +1424,36 @@ QQuickEventPoint *QQuickSinglePointEvent::point(int i) const
     return nullptr;
 }
 
+QQuickPointerEvent *QQuickPointerScrollEvent::reset(QEvent *event)
+{
+    m_event = static_cast<QInputEvent*>(event);
+    if (!event)
+        return this;
+#if QT_CONFIG(wheelevent)
+    if (event->type() == QEvent::Wheel) {
+        auto ev = static_cast<QWheelEvent*>(event);
+        m_device = QQuickPointerDevice::genericMouseDevice();
+        m_device->eventDeliveryTargets().clear();
+        // m_button = Qt::NoButton;
+        m_pressedButtons = ev->buttons();
+        m_angleDelta = QVector2D(ev->angleDelta());
+        m_pixelDelta = QVector2D(ev->pixelDelta());
+        m_phase = ev->phase();
+        m_synthSource = ev->source();
+        m_inverted = ev->inverted();
+
+        m_point->reset(Qt::TouchPointMoved, ev->posF(), quint64(1) << 24, ev->timestamp()); // mouse has device ID 1
+    }
+#endif
+    // TODO else if (event->type() == QEvent::Scroll) ...
+    return this;
+}
+
+void QQuickPointerScrollEvent::localize(QQuickItem *target)
+{
+    m_point->localizePosition(target);
+}
+
 QQuickEventPoint *QQuickPointerTouchEvent::point(int i) const
 {
     if (i >= 0 && i < m_pointCount)
@@ -1698,6 +1728,39 @@ qreal QQuickPointerNativeGestureEvent::value() const
 #endif // QT_CONFIG(gestures)
 
 /*!
+    Returns whether the scroll event has Qt::ScrollBegin phase. On touchpads
+    which provide phase information, this is true when the fingers are placed
+    on the touchpad and scrolling begins. On other devices where this
+    information is not available, it remains false.
+*/
+bool QQuickPointerScrollEvent::isPressEvent() const
+{
+    return phase() == Qt::ScrollBegin;
+}
+
+/*!
+    Returns true when the scroll event has Qt::ScrollUpdate phase, or when the
+    phase is unknown. Some multi-touch-capable touchpads and trackpads provide
+    phase information; whereas ordinary mouse wheels and other types of
+    trackpads do not, and in such cases this is always true.
+*/
+bool QQuickPointerScrollEvent::isUpdateEvent() const
+{
+    return phase() == Qt::ScrollUpdate || phase() == Qt::NoScrollPhase;
+}
+
+/*!
+    Returns whether the scroll event has Qt::ScrollBegin phase. On touchpads
+    which provide phase information, this is true when the fingers are lifted
+    from the touchpad. On other devices where this information is not
+    available, it remains false.
+*/
+bool QQuickPointerScrollEvent::isReleaseEvent() const
+{
+    return phase() == Qt::ScrollEnd;
+}
+
+/*!
     \internal
     Returns a pointer to the QQuickEventPoint which has the \a pointId as
     \l {QQuickEventPoint::pointId}{pointId}.
diff --git a/src/quick/items/qquickevents_p_p.h b/src/quick/items/qquickevents_p_p.h
index 1f6abdec84..2439193ef1 100644
--- a/src/quick/items/qquickevents_p_p.h
+++ b/src/quick/items/qquickevents_p_p.h
@@ -69,6 +69,7 @@ class QQuickPointerMouseEvent;
 #if QT_CONFIG(gestures)
 class QQuickPointerNativeGestureEvent;
 #endif
+class QQuickPointerScrollEvent;
 class QQuickPointerTabletEvent;
 class QQuickPointerTouchEvent;
 class QQuickPointerHandler;
@@ -419,12 +420,14 @@ public: // helpers for C++ only (during event delivery)
 #if QT_CONFIG(gestures)
     virtual QQuickPointerNativeGestureEvent *asPointerNativeGestureEvent() { return nullptr; }
 #endif
+    virtual QQuickPointerScrollEvent *asPointerScrollEvent() { return nullptr; }
     virtual const QQuickPointerMouseEvent *asPointerMouseEvent() const { return nullptr; }
     virtual const QQuickPointerTouchEvent *asPointerTouchEvent() const { return nullptr; }
     virtual const QQuickPointerTabletEvent *asPointerTabletEvent() const { return nullptr; }
 #if QT_CONFIG(gestures)
     virtual const QQuickPointerNativeGestureEvent *asPointerNativeGestureEvent() const { return nullptr; }
 #endif
+    virtual const QQuickPointerScrollEvent *asPointerScrollEvent() const { return nullptr; }
     virtual bool allPointsAccepted() const = 0;
     virtual bool allUpdatedPointsAccepted() const = 0;
     virtual bool allPointsGrabbed() const = 0;
@@ -560,6 +563,50 @@ public:
 };
 #endif // QT_CONFIG(gestures)
 
+class Q_QUICK_PRIVATE_EXPORT QQuickPointerScrollEvent : public QQuickSinglePointEvent
+{
+    Q_OBJECT
+    Q_PROPERTY(QVector2D angleDelta READ angleDelta CONSTANT)
+    Q_PROPERTY(QVector2D pixelDelta READ pixelDelta CONSTANT)
+    Q_PROPERTY(bool hasAngleDelta READ hasAngleDelta CONSTANT)
+    Q_PROPERTY(bool hasPixelDelta READ hasPixelDelta CONSTANT)
+    Q_PROPERTY(bool inverted READ isInverted CONSTANT)
+
+public:
+    QQuickPointerScrollEvent(QObject *parent = nullptr, QQuickPointerDevice *device = nullptr)
+        : QQuickSinglePointEvent(parent, device) { }
+
+    QQuickPointerEvent *reset(QEvent *) override;
+    void localize(QQuickItem *target) override;
+    bool isPressEvent() const override;
+    bool isUpdateEvent() const override;
+    bool isReleaseEvent() const override;
+    QQuickPointerScrollEvent *asPointerScrollEvent() override { return this; }
+    const QQuickPointerScrollEvent *asPointerScrollEvent() const override { return this; }
+    QVector2D angleDelta() const { return m_angleDelta; }
+    QVector2D pixelDelta() const { return m_pixelDelta; }
+    bool hasAngleDelta() const { return !angleDelta().isNull(); }
+    bool hasPixelDelta() const { return !pixelDelta().isNull(); }
+    bool isInverted() const { return m_inverted; }
+    Qt::ScrollPhase phase() const { return m_phase; }
+
+private:
+    // TODO add QQuickPointerDevice source() whenever QInputEvent is extended to have a source device
+    // then maybe Qt::MouseEventSource synthSource() will be obsolete... that's why it's not public now
+    Qt::MouseEventSource synthSource() const { return m_synthSource; }
+
+private:
+    QVector2D m_angleDelta;
+    QVector2D m_pixelDelta;
+    Qt::ScrollPhase m_phase = Qt::NoScrollPhase;
+    Qt::MouseEventSource m_synthSource = Qt::MouseEventNotSynthesized;
+    bool m_inverted = false;
+
+    friend class QQuickWindowPrivate;
+
+    Q_DISABLE_COPY(QQuickPointerScrollEvent)
+};
+
 
 // ### Qt 6: move this to qtbase, replace QTouchDevice and the enums in QTabletEvent
 class Q_QUICK_PRIVATE_EXPORT QQuickPointerDevice : public QObject