OSX: WindowTransparentForInput QNSView pass events to next responder

The default implementation (in the super class) passes the event
to the next responder.  This seems to be one valid way to handle
the Qt::WindowTransparentForInput flag.  So if a non-alien widget
for which a native NSView is created has the flag
WA_TransparentForMouseEvents, that means the window will have
Qt::WindowTransparentForInput, and the NSView which is created
on its behalf will pass on each event so that other NSViews have
a chance to handle it.  (It will also try to reject becoming
first responder, but that doesn't seem to be enough for the following
events to be passed on.)  This is a followup to
I979be9f72f7d225d7b960fc5db4c3956d2749982 which purported to
obey the WindowTransparentForInput flag, but actually doesn't.

Change-Id: Ia72a3573c2e3cbfa7ede70bee41ac36df6924598
Task-number: QTBUG-28816
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>

src/plugins/platforms/cocoa/qnsview.mm

@@ -410,6 +410,8 @@ static QTouchDevice *touchDevice = 0;
 
 - (BOOL)becomeFirstResponder
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return NO;
     QWindow *focusWindow = m_window;
 
     // For widgets we need to do a bit of trickery as the window
@@ -427,6 +429,8 @@ static QTouchDevice *touchDevice = 0;
 {
     if (m_window->flags() & Qt::WindowDoesNotAcceptFocus)
         return NO;
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return NO;
     if ((m_window->flags() & Qt::ToolTip) == Qt::ToolTip)
         return NO;
     return YES;
@@ -434,7 +438,9 @@ static QTouchDevice *touchDevice = 0;
 
 - (BOOL)acceptsFirstMouse:(NSEvent *)theEvent
 {
-    Q_UNUSED(theEvent);
+    Q_UNUSED(theEvent)
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return NO;
     return YES;
 }
 
@@ -539,6 +545,8 @@ static QTouchDevice *touchDevice = 0;
 
 - (void)mouseDown:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super mouseDown:theEvent];
     m_sendUpAsRightButton = false;
     if (m_platformWindow->m_activePopupWindow) {
         QWindowSystemInterface::handleCloseEvent(m_platformWindow->m_activePopupWindow);
@@ -563,6 +571,8 @@ static QTouchDevice *touchDevice = 0;
 
 - (void)mouseDragged:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super mouseDragged:theEvent];
     if (!(m_buttons & Qt::LeftButton))
         qWarning("QNSView mouseDragged: Internal mouse button tracking invalid (missing Qt::LeftButton)");
     [self handleMouseEvent:theEvent];
@@ -570,6 +580,8 @@ static QTouchDevice *touchDevice = 0;
 
 - (void)mouseUp:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super mouseUp:theEvent];
     if (m_sendUpAsRightButton) {
         m_buttons &= ~Qt::RightButton;
         m_sendUpAsRightButton = false;
@@ -614,11 +626,15 @@ static QTouchDevice *touchDevice = 0;
 
 - (void)mouseMoved:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super mouseMoved:theEvent];
     [self handleMouseEvent:theEvent];
 }
 
 - (void)mouseEntered:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super mouseEntered:theEvent];
     QPoint windowPoint, screenPoint;
     [self convertFromEvent:theEvent toWindowPoint:&windowPoint andScreenPoint:&screenPoint];
     QWindowSystemInterface::handleEnterEvent(m_window, windowPoint, screenPoint);
@@ -626,18 +642,23 @@ static QTouchDevice *touchDevice = 0;
 
 - (void)mouseExited:(NSEvent *)theEvent
 {
-    Q_UNUSED(theEvent);
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super mouseExited:theEvent];
     QWindowSystemInterface::handleLeaveEvent(m_window);
 }
 
 - (void)rightMouseDown:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super rightMouseDown:theEvent];
     m_buttons |= Qt::RightButton;
     [self handleMouseEvent:theEvent];
 }
 
 - (void)rightMouseDragged:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super rightMouseDragged:theEvent];
     if (!(m_buttons & Qt::RightButton))
         qWarning("QNSView rightMouseDragged: Internal mouse button tracking invalid (missing Qt::RightButton)");
     [self handleMouseEvent:theEvent];
@@ -645,18 +666,24 @@ static QTouchDevice *touchDevice = 0;
 
 - (void)rightMouseUp:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super rightMouseUp:theEvent];
     m_buttons &= ~Qt::RightButton;
     [self handleMouseEvent:theEvent];
 }
 
 - (void)otherMouseDown:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super otherMouseDown:theEvent];
     m_buttons |= cocoaButton2QtButton([theEvent buttonNumber]);
     [self handleMouseEvent:theEvent];
 }
 
 - (void)otherMouseDragged:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super otherMouseDragged:theEvent];
     if (!(m_buttons & ~(Qt::LeftButton | Qt::RightButton)))
         qWarning("QNSView otherMouseDragged: Internal mouse button tracking invalid (missing Qt::MiddleButton or Qt::ExtraButton*)");
     [self handleMouseEvent:theEvent];
@@ -664,6 +691,8 @@ static QTouchDevice *touchDevice = 0;
 
 - (void)otherMouseUp:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super otherMouseUp:theEvent];
     m_buttons &= ~cocoaButton2QtButton([theEvent buttonNumber]);
     [self handleMouseEvent:theEvent];
 }
@@ -699,6 +728,8 @@ static QTouchDevice *touchDevice = 0;
 #ifndef QT_NO_WHEELEVENT
 - (void)scrollWheel:(NSEvent *)theEvent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super scrollWheel:theEvent];
     const EventRef carbonEvent = (EventRef)[theEvent eventRef];
     const UInt32 carbonEventKind = carbonEvent ? ::GetEventKind(carbonEvent) : 0;
     const bool scrollEvent = carbonEventKind == kEventMouseScroll;
@@ -864,11 +895,15 @@ static QTouchDevice *touchDevice = 0;
 
 - (void)keyDown:(NSEvent *)nsevent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super keyDown:nsevent];
     [self handleKeyEvent:nsevent eventType:int(QEvent::KeyPress)];
 }
 
 - (void)keyUp:(NSEvent *)nsevent
 {
+    if (m_window->flags() & Qt::WindowTransparentForInput)
+        return [super keyUp:nsevent];
     [self handleKeyEvent:nsevent eventType:int(QEvent::KeyRelease)];
 }
 

src/widgets/kernel/qwidget.cpp

@@ -1083,7 +1083,8 @@ void QWidgetPrivate::adjustFlags(Qt::WindowFlags &flags, QWidget *w)
     else
         flags |= Qt::WindowTitleHint | Qt::WindowSystemMenuHint | Qt::WindowMinimizeButtonHint |
                 Qt::WindowMaximizeButtonHint | Qt::WindowCloseButtonHint | Qt::WindowFullscreenButtonHint;
-
+    if (w->testAttribute(Qt::WA_TransparentForMouseEvents))
+        flags |= Qt::WindowTransparentForInput;
 }
 
 void QWidgetPrivate::init(QWidget *parentWidget, Qt::WindowFlags f)