How to create of Viewport size on Rectangle selection

Jaisan

How to change the viewport size in the view on Rubber band selection of the items.
only view should be zoomed with out change in any items size or positions.

SGaist

Hi and welcome to devnet,

What view are you talking about ?

Jaisan

here i am going to use ViewPort in QGraphicsView.

all items which intersects the rubberband drag should be drawn inside the viewport of the viewscreen.

raven-worx

@Jaisan
Untested, so forgive any possible compile issues, but it should give you an idea:

class MyGraphicsView : public QGraphicsVIew
{
public:
    MyGraphicsView( QWidget* parent = Q_NULLPTR )
        : QGraphicsView(parent)
    {
        mRubberBand = new QRubberBand( QRubberBand::Rectangle, this->viewport() );
        mRubberBand->hide();
    }
    
protected:
    QRubberBand* mRubberBand;
    QPoint mOrigin;

    virtual bool viewportEvent(QEvent * event)
    {
        switch( event->type() )
        {
            case QEvent::MouseButtonPress:
            {
                QMouseEvent* me = static_cast<QMouseEvent*>( event );
                if( me->button() == Qt::LeftButton )
                {
                    mOrigin = me->pos();
                    mRubberBand->setGeometry(QRect(origin, QSize()));
                    mRubberBand->show();
                }
            }
            break;
            case QEvent::MouseMove:
            {
                if( mRubberBand.isVisible() )
                {
                    QMouseEvent* me = static_cast<QMouseEvent*>( event );
                    mRubberBand->setGeometry(QRect(mOrigin, me->pos()).normalized());
                }
            }
            break;
            case QEvent::MouseButtonRelease:
            {
                if( mRubberBand.isVisible() )
                {
                    mRubberBand->hide();
                
                    QList<QGraphicsItem*> items = this->items( mRubberBand->geometry() );
                
                    QRectF itemsRect;
                    foreach( QGraphicsItem* item, items )
                         itemsRect |= item->screneRect();
                    if( itemsRect.isValid() )
                         this->fitInView( itemsRect );
                }
            }
            break;
        }
        
        return QGraphicsView::viewportEvent(event);
    }
};

Jaisan

thanks its works fine