Mac: Implement unified toolbar look for QTabBar

Extend the unified title and toolbar gradient to 
tabs in document mode that are adjacent unified
tool bars.

Change the updateMacBorderMetrics() function to
register the tab bar geometry and visibility status
with the Cocoa platform plugin. The Cocoa platform
plugin will then merge this area with other registered
areas if possible.

Add QCocoaNativeInterface::testContentBorderPosition(). 
This function tests whether the given point is within 
the unified title and toolbar area.

Use testContentBorderPosition() in QMacStyle to enable 
code paths that skips drawing the QToolBar bottom 
separator line and paints the active tab background 
with transparent pixels to make the background gradient 
visible.

Change-Id: I2b70f9bb0c2c59af053a691a7df538f958783dab
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

1 files changed, 43 insertions, 28 deletions

diff --git a/src/widgets/widgets/qtabbar.cpp b/src/widgets/widgets/qtabbar.cpp
index b47d65f561..789ec2f6fd 100644
--- a/src/widgets/widgets/qtabbar.cpp
+++ b/src/widgets/widgets/qtabbar.cpp
@@ -56,6 +56,9 @@
 #ifndef QT_NO_ACCESSIBILITY
 #include "qaccessible.h"
 #endif
+#ifdef Q_OS_OSX
+#include <qpa/qplatformnativeinterface.h>
+#endif
 
 #include "qdebug.h"
 #include "private/qtabbar_p.h"
@@ -80,35 +83,44 @@ inline static bool verticalTabs(QTabBar::Shape shape)
 
 void QTabBarPrivate::updateMacBorderMetrics()
 {
-#if defined(Q_WS_MAC)
-    if (QSysInfo::MacintoshVersion >= QSysInfo::MV_10_5) {
-        Q_Q(QTabBar);
-        ::HIContentBorderMetrics metrics;
-
-        // TODO: get metrics to preserve the bottom value
-        // TODO: test tab bar position
-
-        OSWindowRef window = qt_mac_window_for(q);
-
-        // push base line separator down to the client are so we can paint over it (Carbon)
-        metrics.top = (documentMode && q->isVisible()) ? 1 : 0;
-        metrics.bottom = 0;
-        metrics.left = 0;
-        metrics.right = 0;
-        qt_mac_updateContentBorderMetricts(window, metrics);
-        // In Cocoa we need to keep track of the drawRect method.
-        // If documentMode is enabled we need to change it, unless
-        // a toolbar is present.
-        // Notice that all the information is kept in the window,
-        // that's why we get the private widget for it instead of
-        // the private widget for this widget.
-        QWidgetPrivate *privateWidget = qt_widget_private(q->window());
-        if(privateWidget)
-            privateWidget->changeMethods = documentMode;
-        // Since in Cocoa there is no simple way to remove the baseline, so we just ask the
-        // top level to do the magic for us.
-        privateWidget->syncUnifiedMode();
+#if defined(Q_OS_OSX)
+    Q_Q(QTabBar);
+    // Extend the unified title and toolbar area to cover the tab bar iff
+    // 1) the tab bar is in document mode
+    // 2) the tab bar is directly below an "unified" area.
+    // The extending itself is done in the Cocoa platform plugin and Mac style,
+    // this function registers geometry and visibility state for the tab bar.
+
+    // Calculate geometry
+    int upper, lower;
+    if (documentMode) {
+        QPoint windowPos = q->mapTo(q->window(), QPoint(0,0));
+        upper = windowPos.y();
+        int tabStripHeight = q->tabSizeHint(0).height();
+        int pixelTweak = -3;
+        lower = upper + tabStripHeight + pixelTweak;
+    } else {
+        upper = 0;
+        lower = 0;
     }
+
+    QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
+    quintptr identifier = reinterpret_cast<quintptr>(q);
+
+    // Set geometry
+    QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
+        nativeInterface->nativeResourceFunctionForIntegration("registerContentBorderArea");
+    if (!function)
+        return; // Not Cocoa platform plugin.
+    typedef void (*RegisterContentBorderAreaFunction)(QWindow *window, quintptr identifier, int upper, int lower);
+    (reinterpret_cast<RegisterContentBorderAreaFunction>(function))(q->window()->windowHandle(), identifier, upper, lower);
+
+    // Set visibility state
+    function = nativeInterface->nativeResourceFunctionForIntegration("setContentBorderAreaEnabled");
+    if (!function)
+        return;
+    typedef void (*SetContentBorderAreaEnabledFunction)(QWindow *window, quintptr identifier, bool enable);
+    (reinterpret_cast<SetContentBorderAreaEnabledFunction>(function))(q->window()->windowHandle(), identifier, q->isVisible());
 #endif
 }
 
@@ -1502,6 +1514,9 @@ bool QTabBar::event(QEvent *event)
                                             || (!d->rightB->isHidden() && d->rightB->geometry().contains(pos));
         if (!isEventInCornerButtons)
             emit tabBarDoubleClicked(tabAt(pos));
+    } else if (event->type() == QEvent::Move) {
+        d->updateMacBorderMetrics();
+        return QWidget::event(event);
     }
     return QWidget::event(event);
 }