5 files changed, 51 insertions, 6 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index d8457bc0418..76386a30a00 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -84,6 +84,7 @@
 #include "private/qcursor_p.h"
 #include "private/qopenglcontext_p.h"
 #include "private/qinputdevicemanager_p.h"
+#include "private/qtouchdevice_p.h"

 #include "private/qdnd_p.h"
 #include <qpa/qplatformthemefactory_p.h>
@@ -1944,7 +1945,8 @@ void QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::Mo
 points << point;

 QEvent::Type type;
- QList<QTouchEvent::TouchPoint> touchPoints = QWindowSystemInterfacePrivate::fromNativeTouchPoints(points, window, &type);
+ QList<QTouchEvent::TouchPoint> touchPoints =
+ QWindowSystemInterfacePrivate::fromNativeTouchPoints(points, window, QTouchDevicePrivate::get(m_fakeTouchDevice)->id, &type);

 QWindowSystemInterfacePrivate::TouchEvent fake(window, e->timestamp, type, m_fakeTouchDevice, touchPoints, e->modifiers);
 fake.flags |= QWindowSystemInterfacePrivate::WindowSystemEvent::Synthetic;
diff --git a/src/gui/kernel/qtouchdevice.h b/src/gui/kernel/qtouchdevice.h
index 0fb24e47bf4..c98aa692369 100644
--- a/src/gui/kernel/qtouchdevice.h
+++ b/src/gui/kernel/qtouchdevice.h
@@ -87,6 +87,7 @@ public:

 private:
 QTouchDevicePrivate *d;
+ friend class QTouchDevicePrivate;
 };

 Q_DECLARE_OPERATORS_FOR_FLAGS(QTouchDevice::Capabilities)
diff --git a/src/gui/kernel/qtouchdevice_p.h b/src/gui/kernel/qtouchdevice_p.h
index 203d9fca742..18d2af46a7d 100644
--- a/src/gui/kernel/qtouchdevice_p.h
+++ b/src/gui/kernel/qtouchdevice_p.h
@@ -64,16 +64,21 @@ public:
 : type(QTouchDevice::TouchScreen),
 caps(QTouchDevice::Position),
 maxTouchPoints(1)
- { }
+ {
+ static quint8 nextId = 2; // device 0 is not used, device 1 is for mouse device
+ id = nextId++;
+ }

 QTouchDevice::DeviceType type;
 QTouchDevice::Capabilities caps;
 QString name;
 int maxTouchPoints;
+ quint8 id;

 static void registerDevice(const QTouchDevice *dev);
 static void unregisterDevice(const QTouchDevice *dev);
 static bool isRegistered(const QTouchDevice *dev);
+ static QTouchDevicePrivate *get(QTouchDevice *q) { return q->d; }
 };

 QT_END_NAMESPACE
diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index bb778bc5fc7..ecc84e73d74 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -460,9 +460,40 @@ void QWindowSystemInterface::handleTouchEvent(QWindow *w, QTouchDevice *device,
 handleTouchEvent(w, time, device, points, mods);
 }

+static int g_nextPointId = 1;
+
+// map from device-independent point id (arbitrary) to "Qt point" ids
+typedef QMap<quint64, int> PointIdMap;
+Q_GLOBAL_STATIC(PointIdMap, g_pointIdMap)
+
+/*!
+ This function maps potentially arbitrary point ids \a pointId in the 32 bit
+ value space to start from 1 and increase incrementally for each touch point
+ held down. If all touch points are released it will reset the id back to 1
+ for the following touch point.
+
+ We can then assume that the touch points ids will never become too large,
+ and it will then put the device identifier \a deviceId in the upper 8 bits.
+ This leaves us with max 255 devices, and 16.7M taps without full release
+ before we run out of value space.
+*/
+static int acquireCombinedPointId(quint8 deviceId, int pointId)
+{
+ quint64 combinedId64 = (quint64(deviceId) << 32) + pointId;
+ auto it = g_pointIdMap->constFind(combinedId64);
+ int uid;
+ if (it == g_pointIdMap->constEnd()) {
+ uid = g_nextPointId++;
+ g_pointIdMap->insert(combinedId64, uid);
+ } else {
+ uid = *it;
+ }
+ return (deviceId << 24) + uid;
+}
+
 QList<QTouchEvent::TouchPoint>
 QWindowSystemInterfacePrivate::fromNativeTouchPoints(const QList<QWindowSystemInterface::TouchPoint> &points,
- const QWindow *window,
+ const QWindow *window, quint8 deviceId,
 QEvent::Type *type)
 {
 QList<QTouchEvent::TouchPoint> touchPoints;
@@ -473,7 +504,7 @@ QList<QTouchEvent::TouchPoint>
 QList<QWindowSystemInterface::TouchPoint>::const_iterator point = points.constBegin();
 QList<QWindowSystemInterface::TouchPoint>::const_iterator end = points.constEnd();
 while (point != end) {
- p.setId(point->id);
+ p.setId(acquireCombinedPointId(deviceId, point->id));
 if (point->uniqueId >= 0)
 p.setUniqueId(point->uniqueId);
 p.setPressure(point->pressure);
@@ -506,6 +537,11 @@ QList<QTouchEvent::TouchPoint>
 *type = QEvent::TouchEnd;
 }

+ if (states == Qt::TouchPointReleased) {
+ g_nextPointId = 1;
+ g_pointIdMap->clear();
+ }
+
 return touchPoints;
 }

@@ -540,7 +576,8 @@ void QWindowSystemInterface::handleTouchEvent(QWindow *tlw, ulong timestamp, QTo
 return;

 QEvent::Type type;
- QList<QTouchEvent::TouchPoint> touchPoints = QWindowSystemInterfacePrivate::fromNativeTouchPoints(points, tlw, &type);
+ QList<QTouchEvent::TouchPoint> touchPoints =
+ QWindowSystemInterfacePrivate::fromNativeTouchPoints(points, tlw, QTouchDevicePrivate::get(device)->id, &type);

 QWindowSystemInterfacePrivate::TouchEvent *e =
 new QWindowSystemInterfacePrivate::TouchEvent(tlw, timestamp, type, device, touchPoints, mods);
diff --git a/src/gui/kernel/qwindowsysteminterface_p.h b/src/gui/kernel/qwindowsysteminterface_p.h
index f471e1f550c..e48a77a8ea9 100644
--- a/src/gui/kernel/qwindowsysteminterface_p.h
+++ b/src/gui/kernel/qwindowsysteminterface_p.h
@@ -503,7 +503,7 @@ public:

 static QList<QTouchEvent::TouchPoint>
 fromNativeTouchPoints(const QList<QWindowSystemInterface::TouchPoint> &points,
- const QWindow *window, QEvent::Type *type = Q_NULLPTR);
+ const QWindow *window, quint8 deviceId, QEvent::Type *type = Q_NULLPTR);
 static QList<QWindowSystemInterface::TouchPoint>
 toNativeTouchPoints(const QList<QTouchEvent::TouchPoint>& pointList,
 const QWindow *window);