1 files changed, 16 insertions, 13 deletions
diff --git a/src/plugins/platforms/ios/quiview.mm b/src/plugins/platforms/ios/quiview.mm
index 444017f4c7..4e720941f9 100644
--- a/src/plugins/platforms/ios/quiview.mm
+++ b/src/plugins/platforms/ios/quiview.mm
@@ -223,26 +223,29 @@
 
 - (void)updateTouchList:(NSSet *)touches withState:(Qt::TouchPointState)state
 {
-    // We deliver touch events in global coordinates. But global in this respect
-    // means the same coordinate system that we use for describing the geometry
-    // of the top level QWindow we're inside. And that would be the coordinate
-    // system of the superview of the UIView that backs that window:
-    QPlatformWindow *topLevel = m_qioswindow;
-    while (QPlatformWindow *topLevelParent = topLevel->parent())
-        topLevel = topLevelParent;
-    UIView *rootView = reinterpret_cast<UIView *>(topLevel->winId()).superview;
-    CGSize rootViewSize = rootView.frame.size;
-
     foreach (UITouch *uiTouch, m_activeTouches.keys()) {
         QWindowSystemInterface::TouchPoint &touchPoint = m_activeTouches[uiTouch];
         if (![touches containsObject:uiTouch]) {
             touchPoint.state = Qt::TouchPointStationary;
         } else {
             touchPoint.state = state;
+
+            // Touch positions are expected to be in QScreen global coordinates, and
+            // as we already have the QWindow positioned at the right place, we can
+            // just map from the local view position to global coordinates.
+            QPoint localViewPosition = fromCGPoint([uiTouch locationInView:self]).toPoint();
+            QPoint globalScreenPosition = m_qioswindow->mapToGlobal(localViewPosition);
+
+            touchPoint.area = QRectF(globalScreenPosition, QSize(0, 0));
+
+            // FIXME: Do we really need to support QTouchDevice::NormalizedPosition?
+            QSize screenSize = m_qioswindow->screen()->geometry().size();
+            touchPoint.normalPosition = QPointF(globalScreenPosition.x() / screenSize.width(),
+                                                globalScreenPosition.y() / screenSize.height());
+
+            // We don't claim that our touch device supports QTouchDevice::Pressure,
+            // but fill in a meaningfull value in case clients use it anyways.
             touchPoint.pressure = (state == Qt::TouchPointReleased) ? 0.0 : 1.0;
-            QPoint touchPos = fromCGPoint([uiTouch locationInView:rootView]).toPoint();
-            touchPoint.area = QRectF(touchPos, QSize(0, 0));
-            touchPoint.normalPosition = QPointF(touchPos.x() / rootViewSize.width, touchPos.y() / rootViewSize.height);
         }
     }
 }