Implement [QNSView isOpaque]

Re-use the QCocoaWindow implementation.

This gives a small performance boost since NSWindow
can skip drawing the background if it knows that the
content view will fill with opaque pixels.

Change-Id: I4a9a14135d890e9132dd1cb0af5a1c1a769d7e2f
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

src/plugins/platforms/cocoa/qcocoawindow.h

@@ -109,6 +109,7 @@ public:
     void raise();
     void lower();
     bool isExposed() const;
+    bool isOpaque() const;
     void propagateSizeHints();
     void setOpacity(qreal level);
     void setMask(const QRegion &region);
@@ -161,8 +162,6 @@ protected:
     QCocoaWindow *parentCocoaWindow() const;
     void syncWindowState(Qt::WindowState newState);
 
-    void updateOpaque();
-
 // private:
 public: // for QNSView
     friend class QCocoaBackingStore;

src/plugins/platforms/cocoa/qcocoawindow.mm

@@ -505,6 +505,14 @@ bool QCocoaWindow::isExposed() const
     return m_isExposed;
 }
 
+bool QCocoaWindow::isOpaque() const
+{
+    bool translucent = (window()->format().alphaBufferSize() > 0
+                        || window()->opacity() < 1
+                        || (m_contentView && [m_contentView hasMask]));
+    return !translucent;
+}
+
 void QCocoaWindow::propagateSizeHints()
 {
     QCocoaAutoReleasePool pool;
@@ -543,20 +551,11 @@ void QCocoaWindow::propagateSizeHints()
     }
 }
 
-void QCocoaWindow::updateOpaque()
-{
-    bool translucent = window()->format().alphaBufferSize() > 0
-            || window()->opacity() < 1
-            || (m_contentView && [m_contentView hasMask]);
-    [m_nsWindow setOpaque:!translucent];
-}
-
-
 void QCocoaWindow::setOpacity(qreal level)
 {
     if (m_nsWindow) {
         [m_nsWindow setAlphaValue:level];
-        updateOpaque();
+        [m_nsWindow setOpaque: isOpaque()];
     }
 }
 
@@ -566,7 +565,7 @@ void QCocoaWindow::setMask(const QRegion &region)
         [m_nsWindow setBackgroundColor:[NSColor clearColor]];
 
     [m_qtView setMaskRegion:&region];
-    updateOpaque();
+    [m_nsWindow setOpaque: isOpaque()];
 }
 
 bool QCocoaWindow::setKeyboardGrabEnabled(bool grab)

src/plugins/platforms/cocoa/qnsview.h

@@ -88,6 +88,7 @@ QT_END_NAMESPACE
 - (BOOL)acceptsFirstResponder;
 - (BOOL)becomeFirstResponder;
 - (BOOL)hasMask;
+- (BOOL)isOpaque;
 
 - (void)resetMouseButtons;
 

src/plugins/platforms/cocoa/qnsview.mm

@@ -310,6 +310,11 @@ static QTouchDevice *touchDevice = 0;
     return m_maskData != 0;
 }
 
+- (BOOL) isOpaque
+{
+    return m_platformWindow->isOpaque();
+}
+
 - (void) setMaskRegion:(const QRegion *)region
 {
     m_shouldInvalidateWindowShadow = true;