Cocoa: disable scroll optimization for certain cases

No reason to use the optimization when only scrolling in one
direction. In those cases we are better off scrolling immidiatly
when requested to minimize the shuffling of
scrolls and repaints done by the application

1 files changed, 6 insertions, 4 deletions

diff --git a/src/gui/kernel/qcocoaview_mac.mm b/src/gui/kernel/qcocoaview_mac.mm
index 1b81699..f0ae886 100644
--- a/src/gui/kernel/qcocoaview_mac.mm
+++ b/src/gui/kernel/qcocoaview_mac.mm
@@ -581,26 +581,28 @@ static int qCocoaViewCount = 0;
 #ifndef QT_NO_WHEELEVENT
     // ### Qt 5: Send one QWheelEvent with dx, dy and dz
 
-    QMacScrollOptimization::initNewScroll();
+    if (deltaX != 0 && deltaY != 0)
+        QMacScrollOptimization::initDelayedScroll();
 
     if (deltaX != 0) {
         QWheelEvent qwe(qlocal, qglobal, deltaX, buttons, keyMods, Qt::Horizontal);
         qt_sendSpontaneousEvent(widgetToGetMouse, &qwe);
     }
 
-    if (deltaY) {
+    if (deltaY != 0) {
         QWheelEvent qwe(qlocal, qglobal, deltaY, buttons, keyMods, Qt::Vertical);
         qt_sendSpontaneousEvent(widgetToGetMouse, &qwe);
     }
 
-    if (deltaZ) {
+    if (deltaZ != 0) {
         // Qt doesn't explicitly support wheels with a Z component. In a misguided attempt to
         // try to be ahead of the pack, I'm adding this extra value.
         QWheelEvent qwe(qlocal, qglobal, deltaZ, buttons, keyMods, (Qt::Orientation)3);
         qt_sendSpontaneousEvent(widgetToGetMouse, &qwe);
     }
 
-    QMacScrollOptimization::performDelayedScroll();
+    if (deltaX != 0 && deltaY != 0)
+        QMacScrollOptimization::performDelayedScroll();
 #endif //QT_NO_WHEELEVENT
 }