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>

src/plugins/platforms/cocoa/qcocoanativeinterface.h

@@ -147,6 +147,10 @@ private:
     // Enables or disiables a content border area.
     static void setContentBorderAreaEnabled(QWindow *window, quintptr identifier, bool enable);
 
+    // Returns true if the given coordinate is inside the current
+    // content border.
+    static bool testContentBorderPosition(QWindow *window, int position);
+
     // Sets a NSToolbar instance for the given QWindow. The
     // toolbar will be attached to the native NSWindow when
     // that is created;

src/plugins/platforms/cocoa/qcocoanativeinterface.mm

@@ -133,6 +133,8 @@ QPlatformNativeInterface::NativeResourceForIntegrationFunction QCocoaNativeInter
         return NativeResourceForIntegrationFunction(QCocoaNativeInterface::setContentBorderEnabled);
     if (resource.toLower() == "setnstoolbar")
         return NativeResourceForIntegrationFunction(QCocoaNativeInterface::setNSToolbar);
+    if (resource.toLower() == "testcontentborderposition")
+        return NativeResourceForIntegrationFunction(QCocoaNativeInterface::testContentBorderPosition);
 
     return 0;
 }
@@ -332,4 +334,15 @@ void QCocoaNativeInterface::setNSToolbar(QWindow *window, void *nsToolbar)
         cocoaWindow->updateNSToolbar();
 }
 
+bool QCocoaNativeInterface::testContentBorderPosition(QWindow *window, int position)
+{
+    if (!window)
+        return false;
+
+    QCocoaWindow *cocoaWindow = static_cast<QCocoaWindow *>(window->handle());
+    if (cocoaWindow)
+        return cocoaWindow->testContentBorderAreaPosition(position);
+    return false;
+}
+
 QT_END_NAMESPACE

src/plugins/platforms/cocoa/qcocoawindow.h

@@ -213,6 +213,7 @@ public:
     void registerContentBorderArea(quintptr identifier, int upper, int lower);
     void setContentBorderAreaEnabled(quintptr identifier, bool enable);
     void setContentBorderEnabled(bool enable);
+    bool testContentBorderAreaPosition(int position) const;
     void applyContentBorderThickness(NSWindow *window);
     void updateNSToolbar();
 

src/plugins/platforms/cocoa/qcocoawindow.mm

@@ -1665,6 +1665,12 @@ void QCocoaWindow::updateNSToolbar()
     [m_nsWindow setShowsToolbarButton:YES];
 }
 
+bool QCocoaWindow::testContentBorderAreaPosition(int position) const
+{
+    return m_nsWindow && m_drawContentBorderGradient &&
+            0 <= position && position < [m_nsWindow contentBorderThicknessForEdge: NSMaxYEdge];
+}
+
 qreal QCocoaWindow::devicePixelRatio() const
 {
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7

src/widgets/styles/qmacstyle_mac.mm

@@ -179,6 +179,19 @@ static bool isVerticalTabs(const QTabBar::Shape shape) {
                 || shape == QTabBar::TriangularWest);
 }
 
+static bool isInMacUnifiedToolbarArea(QWindow *window, int windowY)
+{
+    QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
+    QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
+        nativeInterface->nativeResourceFunctionForIntegration("testContentBorderPosition");
+    if (!function)
+        return false; // Not Cocoa platform plugin.
+
+    typedef bool (*TestContentBorderPositionFunction)(QWindow *, int);
+    return (reinterpret_cast<TestContentBorderPositionFunction>(function))(window, windowY);
+}
+
+
 void drawTabCloseButton(QPainter *p, bool hover, bool active, bool selected)
 {
     // draw background circle
@@ -239,7 +252,7 @@ QRect rotateTabPainter(QPainter *p, QTabBar::Shape shape, QRect tabRect)
     return tabRect;
 }
 
-void drawTabShape(QPainter *p, const QStyleOptionTabV3 *tabOpt)
+void drawTabShape(QPainter *p, const QStyleOptionTabV3 *tabOpt, bool isUnified)
 {
     QRect r = tabOpt->rect;
     p->translate(tabOpt->rect.x(), tabOpt->rect.y());
@@ -256,7 +269,12 @@ void drawTabShape(QPainter *p, const QStyleOptionTabV3 *tabOpt)
         QRect rect(1, 0, width - 2, height);
 
         // fill body
-        if (active) {
+        if (tabOpt->documentMode && isUnified) {
+            p->save();
+            p->setCompositionMode(QPainter::CompositionMode_Source);
+            p->fillRect(rect, QColor(Qt::transparent));
+            p->restore();
+        } else if (active) {
             int d = (QSysInfo::MacintoshVersion >= QSysInfo::MV_10_6) ? 16 : 0;
             p->fillRect(rect, QColor(151 + d, 151 + d, 151 + d));
         } else {
@@ -3733,8 +3751,14 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
             if (const QStyleOptionTabV3 *tabOptV3 = qstyleoption_cast<const QStyleOptionTabV3 *>(opt)) {
                 if (tabOptV3->documentMode) {
                     p->save();
-                    // QRect tabRect = tabOptV3->rect;
-                    drawTabShape(p, tabOptV3);
+                    bool isUnified = false;
+                    if (w) {
+                        QRect tabRect = tabOptV3->rect;
+                        QPoint windowTabStart = w->mapTo(w->window(), tabRect.topLeft());
+                        isUnified = isInMacUnifiedToolbarArea(w->window()->windowHandle(), windowTabStart.y());
+                    }
+
+                    drawTabShape(p, tabOptV3, isUnified);
                     p->restore();
                     return;
                 }
@@ -4442,15 +4466,22 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
                     p->fillRect(opt->rect, Qt::transparent);
                     p->restore();
 
-                    // drow horizontal sepearator line at toolBar bottom.
-                    SInt32 margin;
-                    GetThemeMetric(kThemeMetricSeparatorSize, &margin);
-                    CGRect separatorRect = CGRectMake(opt->rect.left(), opt->rect.bottom(), opt->rect.width(), margin);
-                    HIThemeSeparatorDrawInfo separatorDrawInfo;
-                    separatorDrawInfo.version = 0;
-                    separatorDrawInfo.state = qt_macWindowMainWindow(mainWindow) ? kThemeStateActive : kThemeStateInactive;
-                    QMacCGContext cg(p);
-                    HIThemeDrawSeparator(&separatorRect, &separatorDrawInfo, cg, kHIThemeOrientationNormal);
+                    // Drow a horizontal sepearator line at the toolBar bottom if the "unified" area ends here.
+                    // There might be additional toolbars or other widgets such as tab bars in document
+                    // mode below. Determine this by making a unified toolbar area test for the row below
+                    // this toolbar.
+                    QPoint windowToolbarEnd = w->mapTo(w->window(), opt->rect.bottomLeft());
+                    bool isEndOfUnifiedArea = !isInMacUnifiedToolbarArea(w->window()->windowHandle(), windowToolbarEnd.y() + 1);
+                    if (isEndOfUnifiedArea) {
+                        SInt32 margin;
+                        GetThemeMetric(kThemeMetricSeparatorSize, &margin);
+                        CGRect separatorRect = CGRectMake(opt->rect.left(), opt->rect.bottom(), opt->rect.width(), margin);
+                        HIThemeSeparatorDrawInfo separatorDrawInfo;
+                        separatorDrawInfo.version = 0;
+                        separatorDrawInfo.state = qt_macWindowMainWindow(mainWindow) ? kThemeStateActive : kThemeStateInactive;
+                        QMacCGContext cg(p);
+                        HIThemeDrawSeparator(&separatorRect, &separatorDrawInfo, cg, kHIThemeOrientationNormal);
+                    }
                     break;
                 }
             }

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;
+#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.
 
-        // 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();
+    // 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);
 }

src/widgets/widgets/qtabbar_p.h

@@ -182,6 +182,7 @@ public:
     void layoutWidgets(int start = 0);
     void layoutTab(int index);
     void updateMacBorderMetrics();
+    bool isTabInMacUnifiedToolbarArea() const;
     void setupMovableTab();
 
     void makeVisible(int index);