QT图形视图框架：限制图形项不重叠_qgraphicsview防止重叠

QVariant pixmapItem::itemChange(GraphicsItemChange change, const QVariant &value)
{
    if ((change == ItemPositionChange || change == ItemPositionHasChanged) && scene()) // 控件发生移动
    {
        QPointF newPos = value.toPointF();
        QRectF rect(0, 0, scene()->width(), scene()->height());
 
        QList<QGraphicsItem *> list = collidingItems();//碰撞列表
        if(list.size() > 0)
        {
            QGraphicsItem * otherItem = list.first();
            QRectF otherItemRect = otherItem->boundingRect();
            QRectF otherRect = QRectF(otherItem->x(),otherItem->y(),otherItemRect.width(),otherItemRect.height());
 
            if(otherRect.contains(newPos))//左上角
            {
                QPointF tempPoint = otherRect.bottomRight() - newPos;
                if(abs(tempPoint.x()) > abs(tempPoint.y()))
                {
                    newPos.setY(otherItem->y() + otherRect.height() + 2);
                }
                else
                {
                    newPos.setX(otherItem->x() + otherRect.width() + 2);
                }
                this->setPos(newPos);
                return newPos;
            }
 
            QRectF thisRectF = boundingRect();
            QPointF nowPos = QPointF(newPos.x() + thisRectF.width(),newPos.y());
            if(otherRect.contains(nowPos))//右上角
            {
                QPointF tempPoint = otherRect.bottomLeft() - nowPos;
                if(abs(tempPoint.x()) > abs(tempPoint.y()))
                {
                    newPos.setY(otherItem->y() + otherRect.height() + 2);
                }
                else
                {
                    newPos.setX(otherItem->x() - thisRectF.width() - 2);
                }
                this->setPos(newPos);
                return newPos;
            }
 
            nowPos = QPointF(newPos.x(),newPos.y() + thisRectF.height());
            if(otherRect.contains(nowPos))//左下角
            {
                QPointF tempPoint = otherRect.topRight() - nowPos;
                if(abs(tempPoint.x()) > abs(tempPoint.y()))
                {
                    newPos.setY(otherItem->y() - thisRectF.height() - 2);
                }
                else
                {
                    newPos.setX(otherItem->x() + otherRect.width() + 2);
                }
                this->setPos(newPos);
                return newPos;
            }
 
            nowPos = QPointF(newPos.x() + thisRectF.width(),newPos.y() + thisRectF.height());
            if(otherRect.contains(nowPos))//右下角
            {
                QPointF tempPoint = otherRect.topLeft() - nowPos;
                if(abs(tempPoint.x()) > abs(tempPoint.y()))
                {
                    newPos.setY(otherItem->y() - thisRectF.height() - 2);
                }
                else
                {
                    newPos.setX(otherItem->x() - otherRect.width() - 2);
                }
                this->setPos(newPos);
                return newPos;
            }
        }
    }
 
    return QGraphicsObject::itemChange(change, value);
}

效果：