OS X: Fix pan gestures.

The QPanGesture recognizer requires single-point touch events. The touch
implementation in Qt 4 would test Qt::WA_TouchPadAcceptSingleTouchEvents
and forward single touch events if set.

Making this work in Qt 5 is a little bit more involved since the platform
plugins don't know about widgets.

Change the Cocoa touch implementation to send single-point touch events
to QWidgetWindow windows only. Make QApplication forward single-point
touch events only if the target widget has the
Qt::WA_TouchPadAcceptSingleTouchEvents attribute set.

Task-number: QTBUG-35893
Change-Id: I68712a5e3efb4ece7a81ca42f49c412e525eeb3a
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index 4818dd7eaa..42a1c0259d 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -4343,7 +4343,16 @@ bool QApplicationPrivate::translateRawTouchEvent(QWidget *window,
         }
         Q_ASSERT(target.data() != 0);
 
-        StatesAndTouchPoints &maskAndPoints = widgetsNeedingEvents[static_cast<QWidget *>(target.data())];
+        QWidget *targetWidget = static_cast<QWidget *>(target.data());
+
+#ifdef Q_OS_OSX
+        // Single-touch events are normally not sent unless WA_TouchPadAcceptSingleTouchEvents is set.
+        // In Qt 4 this check was in OS X-only coode. That behavior is preserved here by the #ifdef.
+        if (touchPoints.count() == 1 && !targetWidget->testAttribute(Qt::WA_TouchPadAcceptSingleTouchEvents))
+            continue;
+#endif
+
+        StatesAndTouchPoints &maskAndPoints = widgetsNeedingEvents[targetWidget];
         maskAndPoints.first |= touchPoint.state();
         maskAndPoints.second.append(touchPoint);
     }