Forward touchEvents to children inside QGraphicsProxyWidget

Just sending the event to the embedded widget is not enough, we
have to perform hit-testing for the different touch points, and
send the event to the child widget under the point. Fortunately,
QApplicationPrivate::translateRawTouchEvent provides the logic
that generates multiple events for groups of touch points.

Since that helper always sent events spontaneously, add an
optional parameter to allow sending of non-spontaneous events.

Add a test case that simulates touch events to different widget
configurations inside a QGraphicsProxyWidget.

Fixes: QTBUG-67819
Task-number: QTBUG-45737
Change-Id: Iffd5c84c64ee2ceadc7e31863675fdf227582c81
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
(cherry picked from commit 1ecf2212fae176b78c9951a37df9e33eb24d4f2d)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

3 files changed, 19 insertions, 12 deletions

diff --git a/src/widgets/graphicsview/qgraphicsproxywidget.cpp b/src/widgets/graphicsview/qgraphicsproxywidget.cpp
index aaddaa894f..2641e24b9a 100644
--- a/src/widgets/graphicsview/qgraphicsproxywidget.cpp
+++ b/src/widgets/graphicsview/qgraphicsproxywidget.cpp
@@ -916,16 +916,17 @@ bool QGraphicsProxyWidget::event(QEvent *event)
     case QEvent::TouchBegin:
     case QEvent::TouchUpdate:
     case QEvent::TouchEnd: {
-        if (event->spontaneous())
-            qt_sendSpontaneousEvent(d->widget, event);
-        else
-            QCoreApplication::sendEvent(d->widget, event);
-
-        if (event->isAccepted())
+        QTouchEvent *touchEvent = static_cast<QTouchEvent *>(event);
+        auto touchPoints = touchEvent->points();
+        bool res = QApplicationPrivate::translateRawTouchEvent(d->widget, touchEvent->pointingDevice(),
+                                                               touchPoints, touchEvent->timestamp(),
+                                                               event->spontaneous());
+        if (res) {
+            event->accept();
             return true;
-
+        }
         break;
-   }
+    }
     default:
         break;
     }
diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index 0daa0cfcb6..b73db6d583 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -3928,7 +3928,8 @@ void QApplicationPrivate::activateImplicitTouchGrab(QWidget *widget, QTouchEvent
 bool QApplicationPrivate::translateRawTouchEvent(QWidget *window,
                                                  const QPointingDevice *device,
                                                  QList<QEventPoint> &touchPoints,
-                                                 ulong timestamp)
+                                                 ulong timestamp,
+                                                 bool spontaneous)
 {
     QApplicationPrivate *d = self;
     // TODO get rid of this QPair
@@ -4030,7 +4031,9 @@ bool QApplicationPrivate::translateRawTouchEvent(QWidget *window,
         {
             // if the TouchBegin handler recurses, we assume that means the event
             // has been implicitly accepted and continue to send touch events
-            if (QApplication::sendSpontaneousEvent(widget, &touchEvent) && touchEvent.isAccepted()) {
+            bool res = spontaneous ? QApplication::sendSpontaneousEvent(widget, &touchEvent)
+                                   : QApplication::sendEvent(widget, &touchEvent);
+            if (res && touchEvent.isAccepted()) {
                 accepted = true;
                 if (!widget.isNull())
                     widget->setAttribute(Qt::WA_WState_AcceptedTouchBeginEvent);
@@ -4043,7 +4046,9 @@ bool QApplicationPrivate::translateRawTouchEvent(QWidget *window,
                 || QGestureManager::gesturePending(widget)
 #endif
                 ) {
-                if (QApplication::sendSpontaneousEvent(widget, &touchEvent) && touchEvent.isAccepted())
+                bool res = spontaneous ? QApplication::sendSpontaneousEvent(widget, &touchEvent)
+                                       : QApplication::sendEvent(widget, &touchEvent);
+                if (res && touchEvent.isAccepted())
                     accepted = true;
                 // widget can be deleted on TouchEnd
                 if (touchEvent.type() == QEvent::TouchEnd && !widget.isNull())
diff --git a/src/widgets/kernel/qapplication_p.h b/src/widgets/kernel/qapplication_p.h
index f690b07924..31dde00dd9 100644
--- a/src/widgets/kernel/qapplication_p.h
+++ b/src/widgets/kernel/qapplication_p.h
@@ -253,7 +253,8 @@ public:
     static bool translateRawTouchEvent(QWidget *widget,
                                        const QPointingDevice *device,
                                        QList<QEventPoint> &touchPoints,
-                                       ulong timestamp);
+                                       ulong timestamp,
+                                       bool spontaneous = true);
     static void translateTouchCancel(const QPointingDevice *device, ulong timestamp);
 
     QPixmap applyQIconStyleHelper(QIcon::Mode mode, const QPixmap& base) const override;