Is there a way to find when resize is done??

[rajji_saini]

Hi,

Is there any signal or a way to check when resize is complete for QWidget?
Actually I want to stop the drawing on my map control when it is being resized and then start it again once the resize is complete.

Regards,
Raj

[viulskiez]

Is there any signal or a way to check when resize is complete for QWidget?

Try reimplement QWidget::resizeEvent or using QObject::eventFilter.

[ChrisW67]

When do you consider the resize "complete"?

You can do something like this, which stops the widget's layout from updating until there has been no resize event for a configurable time:

#include <QtGui>
#include <QDebug>
 
class LazyResizeWidget: public QWidget
{
    Q_OBJECT
public:
    LazyResizeWidget(QWidget *p = 0): QWidget(p) 
    {
        m_timer = new QTimer(this);
        m_timer->setSingleShot(true);
        connect(m_timer, SIGNAL(timeout()), SLOT(resizeStopped()));
 
        // Just for example content
        QFrame *f = new QFrame(this);
        f->setFrameStyle(QFrame::Plain | QFrame::Box);
        QVBoxLayout *l = new QVBoxLayout(this);
        l->addWidget(f);
        setLayout(l);
    }
 
protected:
    void resizeEvent(QResizeEvent *event)
    {
        QLayout *l = layout();
        if (l) {
            m_timer->start(StoppedTimeout);
            l->setEnabled(false);
        }
        QWidget::resizeEvent(event);
    }
 
private slots:
    void resizeStopped()
    {
        QLayout *l = layout();
        if (l) {
            l->setEnabled(true);
            l->update();
        }
    }
 
private:
    enum { StoppedTimeout = 500 };    
    QTimer *m_timer;
};
 
 
int main(int argc, char**argv)
{
    QApplication app(argc, argv);
    LazyResizeWidget w;
    w.resize(640, 480);
    w.show();
    return app.exec();
}
 
#include "main.moc"

#include <QtGui>
#include <QDebug>

class LazyResizeWidget: public QWidget
{
    Q_OBJECT
public:
    LazyResizeWidget(QWidget *p = 0): QWidget(p) 
    {
        m_timer = new QTimer(this);
        m_timer->setSingleShot(true);
        connect(m_timer, SIGNAL(timeout()), SLOT(resizeStopped()));

        // Just for example content
        QFrame *f = new QFrame(this);
        f->setFrameStyle(QFrame::Plain | QFrame::Box);
        QVBoxLayout *l = new QVBoxLayout(this);
        l->addWidget(f);
        setLayout(l);
    }

protected:
    void resizeEvent(QResizeEvent *event)
    {
        QLayout *l = layout();
        if (l) {
            m_timer->start(StoppedTimeout);
            l->setEnabled(false);
        }
        QWidget::resizeEvent(event);
    }

private slots:
    void resizeStopped()
    {
        QLayout *l = layout();
        if (l) {
            l->setEnabled(true);
            l->update();
        }
    }
    
private:
    enum { StoppedTimeout = 500 };    
    QTimer *m_timer;
};


int main(int argc, char**argv)
{
    QApplication app(argc, argv);
    LazyResizeWidget w;
    w.resize(640, 480);
    w.show();
    return app.exec();
}

#include "main.moc"

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[Coises]

Is there any signal or a way to check when resize is complete for QWidget?
Actually I want to stop the drawing on my map control when it is being resized and then start it again once the resize is complete.

Do you mean when the user is resizing the window (by dragging an edge or a corner)?

If so, and if the target platform is Windows, what you need are the WM_ENTERSIZEMOVE and WM_EXITSIZEMOVE messages. I don’t have a good opportunity to test right now, but if QWidget::winEvent gets those messages, you should be able to use them to do what you need.

[rajji_saini]

Thanks Coises ...