Deliver QTabletEvents to pointer handlersv5.15.0-alpha1

At this time, there are not yet any specialized handlers to
do anything specifically with tablet events; but we demonstrate
how to use HoverHandler to detect the type of stylus in use,
and how to use PointHandler to draw on a Canvas.

Unfortunately, events of types TabletEnterProximity and
TabletLeaveProximity are not delivered to the window, only to
QGuiApplication.  So HoverHandler can detect when the stylus is moved
out of its parent Item (as long as it's still hovering over the tablet
surface), but cannot detect when the stylus leaves the tablet completely.
In Qt 5 that would require a custom application subclass
(see qtbase/examples/widgets/widgets/tablet/tabletapplication.cpp).

Fixes: QTBUG-79660
Change-Id: I81fdb99082dc41c0455085e6b6d3952402bf8742
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

1 files changed, 157 insertions, 5 deletions

diff --git a/src/quick/items/qquickevents.cpp b/src/quick/items/qquickevents.cpp
index 0a6faf04af..0a9abb3322 100644
--- a/src/quick/items/qquickevents.cpp
+++ b/src/quick/items/qquickevents.cpp
@@ -658,14 +658,73 @@ QQuickPointerDevice *QQuickPointerDevice::genericMouseDevice()
     return g_genericMouseDevice;
 }
 
-QQuickPointerDevice *QQuickPointerDevice::tabletDevice(qint64 id)
-{
-    auto it = g_tabletDevices->find(id);
+QQuickPointerDevice *QQuickPointerDevice::tabletDevice(const QTabletEvent *event)
+{
+    // QTabletEvent::uniqueId() is the same for the pointy end and the eraser end of the stylus.
+    // We need to make those unique. QTabletEvent::PointerType only needs 2 bits' worth of storage.
+    // The key into g_tabletDevices just needs to be unique; we don't need to extract uniqueId
+    // back out of it, because QQuickPointerDevice stores that separately anyway.
+    // So the shift-and-add can be thought of as a sort of hash function, even though
+    // most of the time the result will be recognizable because the uniqueId MSBs are often 0.
+    qint64 key = event->uniqueId() + (qint64(event->pointerType()) << 60);
+    auto it = g_tabletDevices->find(key);
     if (it != g_tabletDevices->end())
         return it.value();
 
-    // ### Figure out how to populate the tablet devices
-    return nullptr;
+    DeviceType type = UnknownDevice;
+    int buttonCount = 0;
+    Capabilities caps = Position | Pressure | Hover;
+    // TODO Qt 6: we can't know for sure about XTilt or YTilt until we have a
+    // QTabletDevice populated with capabilities provided by QPA plugins
+
+    switch (event->device()) {
+    case QTabletEvent::Stylus:
+        type = QQuickPointerDevice::Stylus;
+        buttonCount = 3;
+        break;
+    case QTabletEvent::RotationStylus:
+        type = QQuickPointerDevice::Stylus;
+        caps |= QQuickPointerDevice::Rotation;
+        buttonCount = 1;
+        break;
+    case QTabletEvent::Airbrush:
+        type = QQuickPointerDevice::Airbrush;
+        buttonCount = 2;
+        break;
+    case QTabletEvent::Puck:
+        type = QQuickPointerDevice::Puck;
+        buttonCount = 3;
+        break;
+    case QTabletEvent::FourDMouse:
+        type = QQuickPointerDevice::Mouse;
+        caps |= QQuickPointerDevice::Rotation;
+        buttonCount = 3;
+        break;
+    default:
+        type = QQuickPointerDevice::UnknownDevice;
+        break;
+    }
+
+    PointerType ptype = GenericPointer;
+    switch (event->pointerType()) {
+    case QTabletEvent::Pen:
+        ptype = Pen;
+        break;
+    case QTabletEvent::Eraser:
+        ptype = Eraser;
+        break;
+    case QTabletEvent::Cursor:
+        ptype = Cursor;
+        break;
+    case QTabletEvent::UnknownPointer:
+        break;
+    }
+
+    QQuickPointerDevice *device = new QQuickPointerDevice(type, ptype, caps, 1, buttonCount,
+        QLatin1String("tablet tool ") + QString::number(event->uniqueId()), event->uniqueId());
+
+    g_tabletDevices->insert(key, device);
+    return device;
 }
 
 /*!
@@ -1284,6 +1343,12 @@ QVector2D QQuickEventPoint::estimatedVelocity() const
 QQuickPointerEvent::~QQuickPointerEvent()
 {}
 
+QQuickPointerMouseEvent::QQuickPointerMouseEvent(QObject *parent, QQuickPointerDevice *device)
+    : QQuickSinglePointEvent(parent, device)
+{
+    m_point = new QQuickEventPoint(this);
+}
+
 QQuickPointerEvent *QQuickPointerMouseEvent::reset(QEvent *event)
 {
     auto ev = static_cast<QMouseEvent*>(event);
@@ -1398,6 +1463,12 @@ void QQuickPointerTouchEvent::localize(QQuickItem *target)
 }
 
 #if QT_CONFIG(gestures)
+QQuickPointerNativeGestureEvent::QQuickPointerNativeGestureEvent(QObject *parent, QQuickPointerDevice *device)
+    : QQuickSinglePointEvent(parent, device)
+{
+    m_point = new QQuickEventPoint(this);
+}
+
 QQuickPointerEvent *QQuickPointerNativeGestureEvent::reset(QEvent *event)
 {
     auto ev = static_cast<QNativeGestureEvent*>(event);
@@ -1560,6 +1631,12 @@ QQuickEventPoint *QQuickSinglePointEvent::point(int i) const
     \note Many platforms provide no such information. On such platforms,
     \c inverted always returns false.
 */
+QQuickPointerScrollEvent::QQuickPointerScrollEvent(QObject *parent, QQuickPointerDevice *device)
+    : QQuickSinglePointEvent(parent, device)
+{
+    m_point = new QQuickEventPoint(this);
+}
+
 QQuickPointerEvent *QQuickPointerScrollEvent::reset(QEvent *event)
 {
     m_event = static_cast<QInputEvent*>(event);
@@ -1832,6 +1909,81 @@ QMouseEvent *QQuickPointerTouchEvent::syntheticMouseEvent(int pointID, QQuickIte
     return &m_synthMouseEvent;
 }
 
+#if QT_CONFIG(tabletevent)
+QQuickPointerTabletEvent::QQuickPointerTabletEvent(QObject *parent, QQuickPointerDevice *device)
+    : QQuickSinglePointEvent(parent, device)
+{
+    m_point = new QQuickEventTabletPoint(this);
+}
+
+QQuickPointerEvent *QQuickPointerTabletEvent::reset(QEvent *event)
+{
+    auto ev = static_cast<QTabletEvent*>(event);
+    m_event = ev;
+    if (!event)
+        return this;
+
+    Q_ASSERT(m_device == QQuickPointerDevice::tabletDevice(ev));
+    m_device->eventDeliveryTargets().clear();
+    m_button = ev->button();
+    m_pressedButtons = ev->buttons();
+    static_cast<QQuickEventTabletPoint *>(m_point)->reset(ev);
+    return this;
+}
+
+QQuickEventTabletPoint::QQuickEventTabletPoint(QQuickPointerTabletEvent *parent)
+  : QQuickEventPoint(parent)
+{
+}
+
+void QQuickEventTabletPoint::reset(const QTabletEvent *ev)
+{
+    Qt::TouchPointState state = Qt::TouchPointStationary;
+    switch (ev->type()) {
+    case QEvent::TabletPress:
+        state = Qt::TouchPointPressed;
+        clearPassiveGrabbers();
+        break;
+    case QEvent::TabletRelease:
+        state = Qt::TouchPointReleased;
+        break;
+    case QEvent::TabletMove:
+        state = Qt::TouchPointMoved;
+        break;
+    default:
+        break;
+    }
+    QQuickEventPoint::reset(state, ev->posF(), 1, ev->timestamp());
+    m_rotation = ev->rotation();
+    m_pressure = ev->pressure();
+    m_tangentialPressure = ev->tangentialPressure();
+    m_tilt = QVector2D(ev->xTilt(), ev->yTilt());
+}
+
+bool QQuickPointerTabletEvent::isPressEvent() const
+{
+    auto me = static_cast<QTabletEvent *>(m_event);
+    return me->type() == QEvent::TabletPress;
+}
+
+bool QQuickPointerTabletEvent::isUpdateEvent() const
+{
+    auto me = static_cast<QTabletEvent *>(m_event);
+    return me->type() == QEvent::TabletMove;
+}
+
+bool QQuickPointerTabletEvent::isReleaseEvent() const
+{
+    auto me = static_cast<QTabletEvent *>(m_event);
+    return me->type() == QEvent::TabletRelease;
+}
+
+QTabletEvent *QQuickPointerTabletEvent::asTabletEvent() const
+{
+    return static_cast<QTabletEvent *>(m_event);
+}
+#endif // QT_CONFIG(tabletevent)
+
 #if QT_CONFIG(gestures)
 bool QQuickPointerNativeGestureEvent::isPressEvent() const
 {