QMainWindow: respect the maximum size of the central widget

Make sure the dock widgets get the available space when the
central widget cannot expand any more.

[ChangeLog][QtWidgets][QMainWindow] Dock widgets will now be resized
properly when the central widget has a fixed size.

Task-number: QTBUG-40410
Change-Id: Id06c07b79aa3102aa41212fa2c621f5fa426fe02
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@theqtcompany.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/tests/auto/widgets/widgets/qmainwindow/tst_qmainwindow.cpp b/tests/auto/widgets/widgets/qmainwindow/tst_qmainwindow.cpp
index ebda07ee0c..27c803b43d 100644
--- a/tests/auto/widgets/widgets/qmainwindow/tst_qmainwindow.cpp
+++ b/tests/auto/widgets/widgets/qmainwindow/tst_qmainwindow.cpp
@@ -137,6 +137,7 @@ private slots:
 #endif
     void addToolbarAfterShow();
     void centralWidgetSize();
+    void fixedSizeCentralWidget();
     void dockWidgetSize();
     void QTBUG2774_stylechange();
     void QTBUG15080_restoreState();
@@ -1737,6 +1738,50 @@ void tst_QMainWindow::centralWidgetSize()
     QTRY_COMPARE(widget.size(), widget.sizeHint());
 }
 
+void tst_QMainWindow::fixedSizeCentralWidget()
+{
+    // QTBUG-40410: dock widgets does not get all the available space when
+    // central widget is fixed size
+    QMainWindow mainWindow;
+    mainWindow.setCorner(Qt::TopLeftCorner, Qt::LeftDockWidgetArea);
+
+    MyWidget widget;
+    widget.setFixedSize(100,100);
+    mainWindow.setCentralWidget(&widget);
+
+    QDockWidget dock("D1");
+    QWidget *child = new MyWidget;
+    dock.setWidget(child);
+    mainWindow.addDockWidget(Qt::TopDockWidgetArea, &dock);
+
+    QDockWidget dock2("D2");
+    dock2.setWidget(new MyWidget);
+    mainWindow.addDockWidget(Qt::LeftDockWidgetArea, &dock2);
+
+    QSize sizeH = mainWindow.sizeHint();
+    QSize mwSize = QSize(sizeH.width(), sizeH.height() * 2);
+    mainWindow.resize(mwSize);
+    mainWindow.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&mainWindow));
+    if (mainWindow.height() < mwSize.height())
+        QSKIP("The screen is too small for this test");
+
+    // first, check that we get more than the size hint when we have more space
+    QTRY_VERIFY(child->height() > child->sizeHint().height());
+    int childHeight = child->height();
+
+    if (qGuiApp->styleHints()->showIsFullScreen())
+        QSKIP("The platform is auto maximizing, so we cannot resize the window");
+
+    // then, check that we get nothing when there is no space
+    mainWindow.resize(100,100);
+    QTRY_COMPARE(child->height(), 0);
+
+    // finally verify that we get the space back when we resize to the old size
+    mainWindow.resize(mwSize);
+    QTRY_COMPARE(child->height(), childHeight);
+}
+
 void tst_QMainWindow::dockWidgetSize()
 {
     QMainWindow mainWindow;