QGuiApplication: send TouchCancel when touch is interrupted by popup

QQuickWindow depends on maintaining state of known touch points
between events, so it needs to be notified when it will not be
receiving the corresponding release event for one or more.
This temporary fix needs to be reverted when we have a proper
event forwarding solution.

Task-number: QTBUG-37371

Change-Id: I5dc40af6feac425be8103c1586f8ebe3a6aad20d
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index c6376b2647..a19eebfb7c 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -2294,6 +2294,18 @@ void QGuiApplicationPrivate::processTouchEvent(QWindowSystemInterfacePrivate::To
 
         if (w->d_func()->blockedByModalWindow) {
             // a modal window is blocking this window, don't allow touch events through
+
+            // QTBUG-37371 temporary fix; TODO: revisit in 5.4 when we have a forwarding solution
+            if (eventType == QEvent::TouchEnd) {
+                // but don't leave dangling state: e.g.
+                // QQuickWindowPrivate::itemForTouchPointId needs to be cleared.
+                QTouchEvent touchEvent(QEvent::TouchCancel,
+                                       e->device,
+                                       e->modifiers);
+                touchEvent.setTimestamp(e->timestamp);
+                touchEvent.setWindow(w);
+                QGuiApplication::sendSpontaneousEvent(w, &touchEvent);
+            }
             continue;
         }