QTouchEvent: add uniqueId and rotation; TUIO: support fiducial tokens

TUIO supports tracking tagged physical objects on touchscreens by
various means (QR codes, RFIDs etc.)  It can detect both position
and rotation.  Likewise, it may be possible for some touchscreens or
drivers to detect orientation of the fingers.  So, just as QTabletEvent
has rotation, each touchpoint needs to include the rotation value.

When using tokens, each object has a permanent unique ID, whereas
QTouchEvent::TouchPoint::id() is a transient ID which usually auto-
increments each time a finger is pressed to the device.  So we need to
make that available too, to identify each token.  Different platforms
may use different kinds of IDs (int, UUID, QR code etc.); however for
TUIO 1.x, the unique IDs are just 32-bit integers.  QPointerUniqueId
is added, storing only a qint64 for now (like QTabletEvent::uniqueId())
but able to be expanded as necessary later on.

Task-number: QTBUG-51844
Change-Id: I04182042f47fa2954728079139a4664a31184b54
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/gui/kernel/qwindowsysteminterface.h b/src/gui/kernel/qwindowsysteminterface.h
index eff3986788..cde70a1102 100644
--- a/src/gui/kernel/qwindowsysteminterface.h
+++ b/src/gui/kernel/qwindowsysteminterface.h
@@ -117,11 +117,14 @@ public:
     static void handleWheelEvent(QWindow *w, ulong timestamp, const QPointF & local, const QPointF & global, int d, Qt::Orientation o, Qt::KeyboardModifiers mods = Qt::NoModifier);
 
     struct TouchPoint {
-        TouchPoint() : id(0), pressure(0), state(Qt::TouchPointStationary), flags(0) { }
+        TouchPoint() : id(0), uniqueId(-1), pressure(0), rotation(0), state(Qt::TouchPointStationary), flags(0) { }
         int id;                 // for application use
+        qint64 uniqueId;        // for TUIO: object/token ID; otherwise empty
+                                // TODO for TUIO 2.0: add registerPointerUniqueID(QPointerUniqueId)
         QPointF normalPosition; // touch device coordinates, (0 to 1, 0 to 1)
         QRectF area;            // the touched area, centered at position in screen coordinates
         qreal pressure;         // 0 to 1
+        qreal rotation;         // 0 means pointing straight up; 0 if unknown (like QTabletEvent::rotation)
         Qt::TouchPointState state; //Qt::TouchPoint{Pressed|Moved|Stationary|Released}
         QVector2D velocity;     // in screen coordinate system, pixels / seconds
         QTouchEvent::TouchPoint::InfoFlags flags;