Honour max-size when docking

Layout will choose a suitable size for the dock widget when
addDockWidget() is called

src/private/multisplitter/Item.cpp

@@ -562,6 +562,11 @@ int Item::minLength(Qt::Orientation o) const
     return Layouting::length(minSize(), o);
 }
 
+int Item::maxLengthHint(Qt::Orientation o) const
+{
+    return Layouting::length(maxSizeHint(), o);
+}
+
 void Item::setLength(int length, Qt::Orientation o)
 {
     Q_ASSERT(length > 0);
@@ -833,6 +838,8 @@ void Item::onWidgetLayoutRequested()
         if (w->minSize() != minSize()) {
             setMinSize(m_guest->minSize());
         }
+
+        setMaxSizeHint(w->maxSizeHint());
     }
 }
 
@@ -1797,8 +1804,8 @@ QSize ItemContainer::minSize() const
 
 QSize ItemContainer::maxSizeHint() const
 {
-    int maxW = 0;
+    int maxW = KDDOCKWIDGETS_MAX_WIDTH;
-    int maxH = 0;
+    int maxH = KDDOCKWIDGETS_MAX_HEIGHT;
 
     if (!isEmpty()) {
         const Item::List visibleChildren = this->visibleChildren();
@@ -1819,7 +1826,7 @@ QSize ItemContainer::maxSizeHint() const
             maxW += separatorWaste;
     }
 
-    return { maxW, maxH };
+    return QSize(maxW, maxH).expandedTo(minSize());
 }
 
 void ItemContainer::Private::resizeChildren(QSize oldSize, QSize newSize, SizingInfo::List &childSizes,
@@ -2087,7 +2094,7 @@ void ItemContainer::restoreChild(Item *item, NeighbourSqueezeStrategy neighbourS
 
     const int available = availableOnSide(item, Side1) + availableOnSide(item, Side2) - Item::separatorThickness;
 
-    const int max = available;
+    const int max = qMin(available, item->maxLengthHint(d->m_orientation));
     const int min = item->minLength(d->m_orientation);
     const int proposed = Layouting::length(item->size(), d->m_orientation);
     const int newLength = qBound(min, proposed, max);
@@ -2289,7 +2296,7 @@ void ItemContainer::layoutEqually(SizingInfo::List &sizes)
 
             const int newItemLenght = qBound(size.minLength(d->m_orientation),
                                              size.length(d->m_orientation) + suggestedToGive,
-                                             size.maxLength(d->m_orientation));
+                                             size.maxLengthHint(d->m_orientation));
             const int toGive = newItemLenght - size.length(d->m_orientation);
 
             if (toGive == 0) {

src/private/multisplitter/Item_p.h

@@ -138,8 +138,8 @@ struct SizingInfo {
         return Layouting::length(minSize, o);
     }
 
-    int maxLength(Qt::Orientation o) const {
+    int maxLengthHint(Qt::Orientation o) const {
-        return Layouting::length(maxSizeHint, o);
+        return qMax(minLength(o), Layouting::length(maxSizeHint, o));
     }
 
     int availableLength(Qt::Orientation o) const {
@@ -193,7 +193,7 @@ struct SizingInfo {
     }
 
     int availableToGrow(Qt::Orientation o) const {
-        return maxLength(o) - length(o);
+        return maxLengthHint(o) - length(o);
     }
 
     QVariantMap toVariantMap() const;
@@ -294,6 +294,7 @@ public:
     int refCount() const;
 
     int minLength(Qt::Orientation) const;
+    int maxLengthHint(Qt::Orientation) const;
 
     QObject *host() const;
     Widget *hostWidget() const;

src/private/multisplitter/tests/tst_multisplitter.cpp

@@ -69,6 +69,19 @@ public:
         }
     }
 
+    void setMaxSize(QSize sz)
+    {
+        if (sz != m_maxSize) {
+            m_maxSize = sz;
+            Q_EMIT layoutInvalidated();
+        }
+    }
+
+
+    QSize maxSizeHint() const override {
+        return m_maxSize;
+    }
+
     void resizeEvent(QResizeEvent *ev) override
     {
         QWidget::resizeEvent(ev);
@@ -97,6 +110,7 @@ Q_SIGNALS:
     void layoutInvalidated();
 private:
     QSize m_minSize = QSize(200, 200);
+    QSize m_maxSize = QSize(KDDOCKWIDGETS_MAX_WIDTH, KDDOCKWIDGETS_MAX_HEIGHT);
 };
 
 static void fatalWarningsMessageHandler(QtMsgType t, const QMessageLogContext &context, const QString &msg)
@@ -181,6 +195,7 @@ private Q_SLOTS:
     void tst_closeAndRestorePreservesPosition();
     void tst_minSizeChangedBeforeRestore();
     void tst_separatorMoveCrash();
+    void tst_maxSizeHonoured1();
 };
 
 class MyHostWidget : public QWidget
@@ -1528,6 +1543,24 @@ void TestMultiSplitter::tst_separatorMoveCrash()
     c->requestSeparatorMove(separator, available5 + 10);
 }
 
+void TestMultiSplitter::tst_maxSizeHonoured1()
+{
+    // Tests that the suggested rect honours max size when adding an item to a layout.
+
+    auto root = createRoot();
+    auto item1 = createItem();
+    auto item2 = createItem();
+    root->insertItem(item1, Item::Location_OnTop);
+    root->setSize_recursive(QSize(3000, 3000));
+
+    auto guest2 = static_cast<MyGuestWidget*>(item2->guestWidget());
+    const int maxHeight = 250;
+    guest2->setMaxSize(QSize(250, maxHeight));
+
+    root->insertItem(item2, Item::Location_OnBottom);
+    QCOMPARE(item2->height(), maxHeight);
+}
+
 int main(int argc, char *argv[])
 {
     bool qpaPassed = false;

tests/tst_docks.cpp

@@ -355,6 +355,7 @@ private Q_SLOTS:
     void tst_lastFloatingPositionIsRestored();
     void tst_moreTitleBarCornerCases();
     void tst_maxSizePropagates();
+    void tst_maxSizeHonouredWhenDropped();
 
 private:
     std::unique_ptr<MultiSplitter> createMultiSplitterFromSetup(MultiSplitterSetup setup, QHash<QWidget *, Frame *> &frameMap) const;
@@ -5332,34 +5333,55 @@ void TestDocks::tst_moreTitleBarCornerCases()
 
 void TestDocks::tst_maxSizePropagates()
 {
-    {
+    // Tests that the DockWidget gets the min and max size of its guest widget
-        // Tests that the DockWidget gets the min and max size of its guest widget
+    EnsureTopLevelsDeleted e;
+    auto dock1 = new DockWidget("dock1");
 
-        auto dock1 = new DockWidget("dock1");
+    auto w = new QWidget();
+    w->setMinimumSize(120, 120);
+    w->setMaximumSize(500, 500);
+    dock1->setWidget(w);
+    dock1->show();
 
-        auto w = new QWidget();
+    QCOMPARE(Widget_qwidget::widgetMinSize(dock1), Widget_qwidget::widgetMinSize(w));
-        w->setMinimumSize(120, 120);
+    QCOMPARE(dock1->maximumSize(), w->maximumSize());
-        w->setMaximumSize(500, 500);
-        dock1->setWidget(w);
-        dock1->show();
 
-        QCOMPARE(Widget_qwidget::widgetMinSize(dock1), Widget_qwidget::widgetMinSize(w));
+    w->setMinimumSize(121, 121);
-        QCOMPARE(dock1->maximumSize(), w->maximumSize());
+    w->setMaximumSize(501, 501);
 
-        w->setMinimumSize(121, 121);
+    Testing::waitForEvent(w, QEvent::LayoutRequest);
-        w->setMaximumSize(501, 501);
 
-        Testing::waitForEvent(w, QEvent::LayoutRequest);
+    QCOMPARE(Widget_qwidget::widgetMinSize(dock1), Widget_qwidget::widgetMinSize(w));
+    QCOMPARE(dock1->maximumSize(), w->maximumSize());
 
-        QCOMPARE(Widget_qwidget::widgetMinSize(dock1), Widget_qwidget::widgetMinSize(w));
+    // Now let's see if our Frame also has proper size-constraints
-        QCOMPARE(dock1->maximumSize(), w->maximumSize());
+    Frame *frame = dock1->frame();
+    QCOMPARE(frame->maximumSize().expandedTo(w->maximumSize()), frame->maximumSize());
 
-        // Now let's see if our Frame also has proper size-constraints
+    delete dock1->window();
-        Frame *frame = dock1->frame();
+}
-        QCOMPARE(frame->maximumSize().expandedTo(w->maximumSize()), frame->maximumSize());
 
-        delete dock1->window();
+void TestDocks::tst_maxSizeHonouredWhenDropped()
-    }
+{
+    EnsureTopLevelsDeleted e;
+    auto m1 = createMainWindow();
+    auto dock1 = new DockWidget("dock1");
+    auto dock2 = new DockWidget("dock2");
+    m1->addDockWidget(dock1, Location_OnTop);
+    m1->resize(2000, 2000);
+
+    dock2->setWidget(new QWidget);
+    const int maxWidth = 200;
+    dock2->widget()->setMaximumSize(maxWidth, 200);
+    m1->addDockWidget(dock2, Location_OnLeft);
+    const int droppedWidth = dock2->frame()->width();
+    QVERIFY(droppedWidth < maxWidth + 50); // +50 to cover any margins and waste by QTabWidget
+
+    // Try again, but now dropping a multisplitter
+    dock2->setFloating(true);
+    auto fw = qobject_cast<FloatingWindow*>(dock2->window());
+    m1->dropArea()->drop(fw, Location_OnLeft, nullptr);
+    QCOMPARE(dock2->frame()->width(), droppedWidth);
 }
 
 int main(int argc, char *argv[])