Reducing the size of a QMdiSubWindow holding a QLabel with QPixmap



  • The question statement says it all. I am able to enlarge the QMdiSubWindow (and the pixmap scales UP, i.e. enlarges, appropriately) but I am not able to reduce its size (i.e. scale the image DOWN or shrink). When trying to scale down though, the border handles of the QMdiSubWindow remain rigidly fixed.

    The code I am using is as follows:
    @class PixmapWidget : public QLabel
    {
    Q_OBJECT
    public:
    PixmapWidget():
    QLabel()
    {
    _pixmap = QPixmap("path\to\images.jpg");
    setPixmap(_pixmap);
    _layout = new QHBoxLayout();
    _layout->setSizeConstraint(QLayout::SetNoConstraint);
    setLayout(_layout);
    setSizePolicy(QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred));
    }

    void resizeEvent(QResizeEvent * event)
    {
        int width = event->size().width();
        int height = event->size().height();
        setPixmap(_pixmap.scaled(width,height));
        QLabel::resizeEvent(event);
    }
    

    protected:
    QPixmap _pixmap;
    QHBoxLayout* _layout;
    };

    int main()
    {
    QMainWindow mainWindow;
    QHBoxLayout* layout = new QHBoxLayout();
    QMdiArea* mdiArea = new QMdiArea();

    mainWindow.setCentralWidget(mdiArea);
    mainWindow.centralWidget()->setLayout(layout);
    layout->setSizeConstraint(QLayout::SetNoConstraint);
    
    QMdiSubWindow* mdiSubWindow = new QMdiSubWindow();
    layout->addWidget(mdiSubWindow);        
    mdiSubWindow->setSizePolicy(QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred));
    mdiSubWindow->layout()->setSizeConstraint(QLayout::SetNoConstraint);
    
    DMSQt::PixmapWidget pixmapWidget;        
    mdiSubWindow->layout()->addWidget(&pixmapWidget);
    
    mainWindow.show();
    qapp.exec();
    

    }@



  • Alright, I found the problem. Apparently, I need to set a minimum size on my text label:

    Adding:

    @setMinimumSize(_pixmap.width(), _pixmap.height());@

    solved the problem.


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