Change QGraphicsScene Rect by dragging QGraphicItems

[airglide]

Hello everyone,

I've a QGraphicsView and a QGraphicsScene, within this scene are QGraphicsitems.
It sounds quiet trivial but I couldn't manage to change the "size" of the scene by dragging an item at the border of the view (->viewport() ).
I've set the size of the scene because I want that the Items are inserted where a click happens. Otherwise it would insert the first item in the middle...

I tried to override the QGraphicsItem::mouseMoveEvent function and then I tried to check if the scene intersects the item (that the item is at the border and not the whole item is shown... , the view should then add some scrollbars to it (like the default behavior) and should expand the whole thing.


thank you for your help

airglide

[airglide]

I've solved the problem more or less, I've to optimize it but the code looks like this:
The class Pixmap inherits from QGraphicsPixmapItem (QGraphicsItem)

void PixmapItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    QRectF theRect = QRectF(scenePos(), boundingRect().size());
    QRectF intersected = QRectF(theRect.intersected(scene()->sceneRect()));
    if(intersected != theRect)
    {
        //the item is outside of sceneRect
        if(theRect.top() != intersected.top())
        {
            //is at bottom
            if(theRect.right() != intersected.right())
            {
                //is right
                qDebug() << "top-right";
                QRectF mRect = scene()->sceneRect();
                mRect.adjust(0,-50,50,0);
                scene()->setSceneRect(mRect);
            }else{
                if(theRect.left() != intersected.left())
                {
                    //is left
                    qDebug() << "top-left";
                    QRectF mRect = scene()->sceneRect();
                    mRect.adjust(-50,-50,0,0);
                    scene()->setSceneRect(mRect);
                }else{
                    //only top
                    qDebug() << "top";
                    QRectF mRect = scene()->sceneRect();
                    mRect.adjust(0,-50,0,0);
                    scene()->setSceneRect(mRect);
                }
            }
        }else{
 
            if(theRect.bottom() != intersected.bottom())
            {
                //is at bottom
                if(theRect.right() != intersected.right())
                {
                    //is right
                    qDebug() << "bottom-right";
                    QRectF mRect = scene()->sceneRect();
                    mRect.adjust(0,0,50,50);
                    scene()->setSceneRect(mRect);
                }else{
                    if(theRect.left() != intersected.left())
                    {
                        //is left
                        qDebug() << "bottom-left";
                        QRectF mRect = scene()->sceneRect();
                        mRect.adjust(-50,0,0,50);
                        scene()->setSceneRect(mRect);
                    }else{
                        //only bottom
                        qDebug() << "bottom";
                        QRectF mRect = scene()->sceneRect();
                        mRect.adjust(0,0,0,50);
                        scene()->setSceneRect(mRect);
                    }
                }
            }else{
                if(theRect.right() != intersected.right())
                {
                    qDebug() << "right";
                    //is right
                    QRectF mRect = scene()->sceneRect();
                    mRect.adjust(0,0,50,0);
                    scene()->setSceneRect(mRect);
                }else{
                    if(theRect.left() != intersected.left())
                    {
                        qDebug() << "left";
                        //is left
                        QRectF mRect = scene()->sceneRect();
                        mRect.adjust(-50,0,0,0);
                        scene()->setSceneRect(mRect);
                    }}
 
            }
        }
    }else{
        qDebug() << "no intersection";
    }
    QGraphicsPixmapItem::mouseMoveEvent(event);
}

void PixmapItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    QRectF theRect = QRectF(scenePos(), boundingRect().size());
    QRectF intersected = QRectF(theRect.intersected(scene()->sceneRect()));
    if(intersected != theRect)
    {
        //the item is outside of sceneRect
        if(theRect.top() != intersected.top())
        {
            //is at bottom
            if(theRect.right() != intersected.right())
            {
                //is right
                qDebug() << "top-right";
                QRectF mRect = scene()->sceneRect();
                mRect.adjust(0,-50,50,0);
                scene()->setSceneRect(mRect);
            }else{
                if(theRect.left() != intersected.left())
                {
                    //is left
                    qDebug() << "top-left";
                    QRectF mRect = scene()->sceneRect();
                    mRect.adjust(-50,-50,0,0);
                    scene()->setSceneRect(mRect);
                }else{
                    //only top
                    qDebug() << "top";
                    QRectF mRect = scene()->sceneRect();
                    mRect.adjust(0,-50,0,0);
                    scene()->setSceneRect(mRect);
                }
            }
        }else{

            if(theRect.bottom() != intersected.bottom())
            {
                //is at bottom
                if(theRect.right() != intersected.right())
                {
                    //is right
                    qDebug() << "bottom-right";
                    QRectF mRect = scene()->sceneRect();
                    mRect.adjust(0,0,50,50);
                    scene()->setSceneRect(mRect);
                }else{
                    if(theRect.left() != intersected.left())
                    {
                        //is left
                        qDebug() << "bottom-left";
                        QRectF mRect = scene()->sceneRect();
                        mRect.adjust(-50,0,0,50);
                        scene()->setSceneRect(mRect);
                    }else{
                        //only bottom
                        qDebug() << "bottom";
                        QRectF mRect = scene()->sceneRect();
                        mRect.adjust(0,0,0,50);
                        scene()->setSceneRect(mRect);
                    }
                }
            }else{
                if(theRect.right() != intersected.right())
                {
                    qDebug() << "right";
                    //is right
                    QRectF mRect = scene()->sceneRect();
                    mRect.adjust(0,0,50,0);
                    scene()->setSceneRect(mRect);
                }else{
                    if(theRect.left() != intersected.left())
                    {
                        qDebug() << "left";
                        //is left
                        QRectF mRect = scene()->sceneRect();
                        mRect.adjust(-50,0,0,0);
                        scene()->setSceneRect(mRect);
                    }}

            }
        }
    }else{
        qDebug() << "no intersection";
    }
    QGraphicsPixmapItem::mouseMoveEvent(event);
}

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