Add QWheelEvent::inverted()

Some consumers of wheel events need to know if the
scrolling direction is inverted in order to provide
consistent behavior.

For example, the scrolling direction of a horizontal
slider should not change when the user toggles the
"natural scrolling" setting on OS X. In this case
the inverted bit will change state and the slider
can compensate.

This change adds a bit to QWheelEvent and sets it
on OS X.

Task-number: QTBUG-35972
Change-Id: I221435dea45d436d570b113bd0e24ee6f6832211
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index 39bc161a7c..7547e58346 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -315,7 +315,8 @@ void QWindowSystemInterface::handleWheelEvent(QWindow *w, const QPointF & local,
     handleWheelEvent(w, time, local, global, pixelDelta, angleDelta, mods, phase, source);
 }
 
-void QWindowSystemInterface::handleWheelEvent(QWindow *tlw, ulong timestamp, const QPointF & local, const QPointF & global, QPoint pixelDelta, QPoint angleDelta, Qt::KeyboardModifiers mods, Qt::ScrollPhase phase, Qt::MouseEventSource source)
+void QWindowSystemInterface::handleWheelEvent(QWindow *tlw, ulong timestamp, const QPointF & local, const QPointF & global, QPoint pixelDelta, QPoint angleDelta, Qt::KeyboardModifiers mods, Qt::ScrollPhase phase,
+                                              Qt::MouseEventSource source, bool invertedScrolling)
 {
     // Qt 4 sends two separate wheel events for horizontal and vertical
     // deltas. For Qt 5 we want to send the deltas in one event, but at the
@@ -333,14 +334,15 @@ void QWindowSystemInterface::handleWheelEvent(QWindow *tlw, ulong timestamp, con
 
     // Simple case: vertical deltas only:
     if (angleDelta.y() != 0 && angleDelta.x() == 0) {
-        e = new QWindowSystemInterfacePrivate::WheelEvent(tlw, timestamp, QHighDpi::fromNativeLocalPosition(local, tlw), QHighDpi::fromNativePixels(global, tlw), pixelDelta, angleDelta, angleDelta.y(), Qt::Vertical, mods, phase, source);
+        e = new QWindowSystemInterfacePrivate::WheelEvent(tlw, timestamp, QHighDpi::fromNativeLocalPosition(local, tlw), QHighDpi::fromNativePixels(global, tlw), pixelDelta, angleDelta, angleDelta.y(), Qt::Vertical,
+                                                          mods, phase, source, invertedScrolling);
         QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
         return;
     }
 
     // Simple case: horizontal deltas only:
     if (angleDelta.y() == 0 && angleDelta.x() != 0) {
-        e = new QWindowSystemInterfacePrivate::WheelEvent(tlw, timestamp, QHighDpi::fromNativeLocalPosition(local, tlw), QHighDpi::fromNativePixels(global, tlw), pixelDelta, angleDelta, angleDelta.x(), Qt::Horizontal, mods, phase, source);
+        e = new QWindowSystemInterfacePrivate::WheelEvent(tlw, timestamp, QHighDpi::fromNativeLocalPosition(local, tlw), QHighDpi::fromNativePixels(global, tlw), pixelDelta, angleDelta, angleDelta.x(), Qt::Horizontal, mods, phase, source, invertedScrolling);
         QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
         return;
     }
@@ -348,12 +350,12 @@ void QWindowSystemInterface::handleWheelEvent(QWindow *tlw, ulong timestamp, con
     // Both horizontal and vertical deltas: Send two wheel events.
     // The first event contains the Qt 5 pixel and angle delta as points,
     // and in addition the Qt 4 compatibility vertical angle delta.
-    e = new QWindowSystemInterfacePrivate::WheelEvent(tlw, timestamp, QHighDpi::fromNativeLocalPosition(local, tlw), QHighDpi::fromNativePixels(global, tlw), pixelDelta, angleDelta, angleDelta.y(), Qt::Vertical, mods, phase, source);
+    e = new QWindowSystemInterfacePrivate::WheelEvent(tlw, timestamp, QHighDpi::fromNativeLocalPosition(local, tlw), QHighDpi::fromNativePixels(global, tlw), pixelDelta, angleDelta, angleDelta.y(), Qt::Vertical, mods, phase, source, invertedScrolling);
     QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
 
     // The second event contains null pixel and angle points and the
     // Qt 4 compatibility horizontal angle delta.
-    e = new QWindowSystemInterfacePrivate::WheelEvent(tlw, timestamp, QHighDpi::fromNativeLocalPosition(local, tlw), QHighDpi::fromNativePixels(global, tlw), QPoint(), QPoint(), angleDelta.x(), Qt::Horizontal, mods, phase, source);
+    e = new QWindowSystemInterfacePrivate::WheelEvent(tlw, timestamp, QHighDpi::fromNativeLocalPosition(local, tlw), QHighDpi::fromNativePixels(global, tlw), QPoint(), QPoint(), angleDelta.x(), Qt::Horizontal, mods, phase, source, invertedScrolling);
     QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
 }