Fixed the sizing of the dock area with fixed size dock widgets

It could happen that a dock area could be too wide. The problem
was that we didn't really care whether or not the tab bar was visible.
We would always take its minimum sizehint into account.

Task-Number: QTBUG-10391
Reviewed-By: gabi
(cherry picked from commit 8f53bf1b99d32caaebe8cbd1d9bd3a7381821988)

2 files changed, 19 insertions, 31 deletions

diff --git a/src/gui/widgets/qdockarealayout.cpp b/src/gui/widgets/qdockarealayout.cpp
index 81189f4..841346c 100644
--- a/src/gui/widgets/qdockarealayout.cpp
+++ b/src/gui/widgets/qdockarealayout.cpp
@@ -223,7 +223,7 @@ static quintptr tabId(const QDockAreaLayoutItem &item)
 QDockAreaLayoutInfo::QDockAreaLayoutInfo()
     : sep(0), dockPos(QInternal::LeftDock), o(Qt::Horizontal), mainWindow(0)
 #ifndef QT_NO_TABBAR
-    , tabbed(false), tabBar(0), tabBarShape(QTabBar::RoundedSouth), tabBarVisible(false)
+    , tabbed(false), tabBar(0), tabBarShape(QTabBar::RoundedSouth)
 #endif
 {
 }
@@ -233,7 +233,7 @@ QDockAreaLayoutInfo::QDockAreaLayoutInfo(int _sep, QInternal::DockPosition _dock
                                             QMainWindow *window)
     : sep(_sep), dockPos(_dockPos), o(_o), mainWindow(window)
 #ifndef QT_NO_TABBAR
-    , tabbed(false), tabBar(0), tabBarShape(static_cast<QTabBar::Shape>(tbshape)), tabBarVisible(false)
+    , tabbed(false), tabBar(0), tabBarShape(static_cast<QTabBar::Shape>(tbshape))
 #endif
 {
 #ifdef QT_NO_TABBAR
@@ -294,8 +294,8 @@ QSize QDockAreaLayoutInfo::minimumSize() const
     rperp(o, result) = b;
 
 #ifndef QT_NO_TABBAR
-    if (tabbed) {
-        QSize tbm = tabBarMinimumSize();
+    QSize tbm = tabBarMinimumSize();
+    if (!tbm.isNull()) {
         switch (tabBarShape) {
             case QTabBar::RoundedNorth:
             case QTabBar::RoundedSouth:
@@ -367,8 +367,8 @@ QSize QDockAreaLayoutInfo::maximumSize() const
     rperp(o, result) = b;
 
 #ifndef QT_NO_TABBAR
-    if (tabbed) {
-        QSize tbh = tabBarSizeHint();
+    QSize tbh = tabBarSizeHint();
+    if (!tbh.isNull()) {
         switch (tabBarShape) {
             case QTabBar::RoundedNorth:
             case QTabBar::RoundedSouth:
@@ -1498,7 +1498,7 @@ void QDockAreaLayoutInfo::apply(bool animate)
         QRect tab_rect;
         QSize tbh = tabBarSizeHint();
 
-        if (tabBarVisible) {
+        if (!tbh.isNull()) {
             switch (tabBarShape) {
                 case QTabBar::RoundedNorth:
                 case QTabBar::TriangularNorth:
@@ -2074,10 +2074,11 @@ void QDockAreaLayoutInfo::updateSeparatorWidgets() const
 #endif //QT_NO_TABBAR
 
 #ifndef QT_NO_TABBAR
-void QDockAreaLayoutInfo::updateTabBar() const
+//returns whether the tabbar is visible or not
+bool QDockAreaLayoutInfo::updateTabBar() const
 {
     if (!tabbed)
-        return;
+        return false;
 
     QDockAreaLayoutInfo *that = const_cast<QDockAreaLayoutInfo*>(this);
 
@@ -2145,12 +2146,8 @@ void QDockAreaLayoutInfo::updateTabBar() const
 
     tabBar->blockSignals(blocked);
 
-    that->tabBarVisible = ( (gap ? 1 : 0) + tabBar->count()) > 1;
-
-    if (changed || !tabBarMin.isValid() | !tabBarHint.isValid()) {
-        that->tabBarMin = tabBar->minimumSizeHint();
-        that->tabBarHint = tabBar->sizeHint();
-    }
+    //returns if the tabbar is visible or not
+    return ( (gap ? 1 : 0) + tabBar->count()) > 1;
 }
 
 void QDockAreaLayoutInfo::setTabBarShape(int shape)
@@ -2158,11 +2155,8 @@ void QDockAreaLayoutInfo::setTabBarShape(int shape)
     if (shape == tabBarShape)
         return;
     tabBarShape = shape;
-    if (tabBar != 0) {
+    if (tabBar != 0)
         tabBar->setShape(static_cast<QTabBar::Shape>(shape));
-        tabBarMin = QSize();
-        tabBarHint = QSize();
-    }
 
     for (int i = 0; i < item_list.count(); ++i) {
         QDockAreaLayoutItem &item = item_list[i];
@@ -2173,22 +2167,18 @@ void QDockAreaLayoutInfo::setTabBarShape(int shape)
 
 QSize QDockAreaLayoutInfo::tabBarMinimumSize() const
 {
-    if (!tabbed)
+    if (!updateTabBar())
         return QSize(0, 0);
 
-    updateTabBar();
-
-    return tabBarMin;
+    return tabBar->minimumSizeHint();
 }
 
 QSize QDockAreaLayoutInfo::tabBarSizeHint() const
 {
-    if (!tabbed)
+    if (!updateTabBar())
         return QSize(0, 0);
 
-    updateTabBar();
-
-    return tabBarHint;
+    return tabBar->sizeHint();
 }
 
 QSet<QTabBar*> QDockAreaLayoutInfo::usedTabBars() const
@@ -2235,7 +2225,7 @@ QRect QDockAreaLayoutInfo::tabContentRect() const
     QRect result = rect;
     QSize tbh = tabBarSizeHint();
 
-    if (tabBarVisible) {
+    if (!tbh.isNull()) {
         switch (tabBarShape) {
             case QTabBar::RoundedNorth:
             case QTabBar::TriangularNorth:
diff --git a/src/gui/widgets/qdockarealayout_p.h b/src/gui/widgets/qdockarealayout_p.h
index 8d46955..0ce2ea1 100644
--- a/src/gui/widgets/qdockarealayout_p.h
+++ b/src/gui/widgets/qdockarealayout_p.h
@@ -208,11 +208,9 @@ public:
     QRect tabContentRect() const;
     bool tabbed;
     QTabBar *tabBar;
-    QSize tabBarMin, tabBarHint;
     int tabBarShape;
-    bool tabBarVisible;
 
-    void updateTabBar() const;
+    bool updateTabBar() const;
     void setTabBarShape(int shape);
     QSize tabBarMinimumSize() const;
     QSize tabBarSizeHint() const;