Problem drawing in QGraphicsView

ivanicy

Hello!

I am drawing a rectangle in a QGraphicsView, but I have a problem doing it:

1cbcb9ca-d756-437e-b16a-61a80fbeb7c9-InkedWhatsApp Image 2021-11-08 at 9.34.33 AM_LI.jpg

This happens when I move the mouse to draw the rectangle.

How can I fix this? When I release the mouse and finish the rectangle, this lines disapear, but it isn't very visual, you know.

Thank you very much!

JonB

@ivanicy
How are you doing this? Are you using a QGraphicsRectItem?

ivanicy

I am using my own class, setting the nodes and the edges. But I was asking about some property in QGraphicsView that solves this problem, but I understand that is a bit more difficult.

JonB

@ivanicy
Then I cannot answer about your own class, looks like you are leaving some trail of lines behind which later get wiped away on refresh. QGraphicsView works by being told what areas of the canvas to update. If you draw something non-permanent it will stay there until you cause that area of the view to be updated, which may leave "artefacts" if you don't get it right.

artwaw

@ivanicy can you show that class please?

ivanicy

It's a very long class, but here are the important functions:

Variables:

    QGraphicsScene *m_scene;
    int id;
    CNode* nodeFirst;
    CNode* nodeSecond;
    QGraphicsRectItem *graphRect;
    QGraphicsSimpleTextItem *textRoi;
    bool m_bExists;
    bool m_bFirstNodeExist;
    bool m_bSelected;
    CNode* nodeMax;
    CNode* nodeMin;
    int m_iId;
    int m_iType;
    int m_iTarget;
    QString m_sId;
    ROIType m_RoiType;
    QPointF m_topLeft, m_topRight, m_bottomLeft, m_bottomRight;
    int globalIncX, globalIncY;
    QPoint punto;
    QString m_sPathNames;
    double m_dCurrentScale;

PRESS:

void CRoi::press(QPointF event, QPointF limitTopLeft, QPointF limitBottomRight){
    if(!m_bFirstNodeExist){
        nodeFirst->setPos(event.x(), event.y());
        if(nodeFirst->pos().x() < limitTopLeft.x()){
//            nodeFirst->setPos(limitTopLeft.x(), nodeFirst->pos().y());
            nodeFirst->setX(limitTopLeft.x());
        }
        if(nodeFirst->pos().x() > limitBottomRight.x()){
//            nodeFirst->setPos(limitBottomRight.x(), nodeFirst->pos().y());
            nodeFirst->setX(limitBottomRight.x());
        }

        if(nodeFirst->pos().y() < limitTopLeft.y()){
//            nodeFirst->setPos(nodeFirst->pos().x(), limitTopLeft.y());
            nodeFirst->setY(limitTopLeft.y());
        }
        if(nodeFirst->pos().y() > limitBottomRight.y()){
//            nodeFirst->setPos(nodeFirst->pos().x(), limitBottomRight.y());
            nodeFirst->setY(limitBottomRight.y());
        }

        switch (m_iType) {
        case 0:
//            graphRect->setPen(QPen(QColor(0x0000FF), 1, Qt::SolidLine));
//            textRoi->setBrush(QBrush(QColor(0x0000FF)));
            graphRect->setPen(QPen(QColor(0xFF871B), 1*m_dCurrentScale, Qt::SolidLine));
            textRoi->setBrush(QBrush(QColor(0xFF871B)));
            m_sId = getSType();//QString("RP%1").arg(QString::number(m_iId+1));
            textRoi->setText(QString("%1 %2").arg(getSType(), QString::number(m_iId+1)));
            break;
        case 1:
            graphRect->setPen(QPen(QColor(0xFF0000), 1*m_dCurrentScale, Qt::SolidLine));
            textRoi->setBrush(QBrush(QColor(0xFF0000)));
            m_sId = getSType();//QString("RP%1").arg(QString::number(m_iId+1));
            textRoi->setText(QString("%1 %2").arg(getSType(), QString::number(m_iId+1)));
            break;
        case 2:
            graphRect->setPen(QPen(QColor(0xFFFB00), 1*m_dCurrentScale, Qt::SolidLine));
            textRoi->setBrush(QBrush(QColor(0xFFFB00)));
            m_sId = getSType();//QString("RP%1").arg(QString::number(m_iId+1));
            textRoi->setText(QString("%1 %2").arg(getSType(), QString::number(m_iId+1)));
            break;
        default:
            graphRect->setPen(QPen(QColor(0xEF7528), 1*m_dCurrentScale, Qt::SolidLine));
            textRoi->setBrush(QBrush(QColor(0xEF7528)));
            m_sId = getSType();//QString("RP%1").arg(QString::number(m_iId+1));
            textRoi->setText(QString("%1 %2").arg(getSType(), QString::number(m_iId+1)));
            break;
        }
        graphRect->resetTransform();
        graphRect->setPos(nodeFirst->pos());
        graphRect->setTransformOriginPoint((event.x() - nodeFirst->pos().x())/2, (event.y() - nodeFirst->pos().y())/2);
        graphRect->setRotation(180);
        m_scene->addItem(graphRect);
        m_scene->addItem(nodeFirst);
        textRoi->setFont(QFont("Arial", 8*m_dCurrentScale));
        textRoi->setPos(event.x()-((textRoi->boundingRect().width()+2))*m_dCurrentScale, event.y()-((textRoi->boundingRect().height()+2))*m_dCurrentScale);
        m_scene->addItem(textRoi);

        m_bFirstNodeExist = true;
    } else if(m_bFirstNodeExist && m_bExists){
        if(graphRect->isSelected() || textRoi->isSelected()){
            nodeFirst->setSelected(true);
            nodeSecond->setSelected(true);
            textRoi->setSelected(true);
            graphRect->setSelected(true);
        }

        if(nodeFirst->isSelected() && nodeSecond->isSelected() && textRoi->isSelected() && graphRect->isSelected())
            m_bSelected = true;
        else
            m_bSelected = false;
    }
    //Radio de los nodos en función de la anchura y altura de las etiquetas.
//    double dRadius = std::max(1.5, std::min(abs(graphRect->rect().width()), abs(graphRect->rect().height()))*0.05);
//    nodeFirst->setNodeRadius(1/dRadius);
//    nodeSecond->setNodeRadius(1/dRadius);
}

MOVE:

void CRoi::move(QPointF event, QPointF limitTopLeft, QPointF limitBottomRight){
    if(!m_bExists && m_bFirstNodeExist){
        nodeSecond->setCursor(Qt::ClosedHandCursor);

        if(event.x() < limitTopLeft.x()){
            nodeSecond->setPos(limitTopLeft.x(), event.y());
        }
        if(event.x() > limitBottomRight.x()){
            nodeSecond->setPos(limitBottomRight.x(), event.y());
        }
        if(event.x() > limitTopLeft.x() && event.x() < limitBottomRight.x()) {
            nodeSecond->setPos(event.x(), event.y());
        }

        if(event.y() < limitTopLeft.y()){
            nodeSecond->setPos(nodeSecond->pos().x(), limitTopLeft.y());
        }
        if(event.y() > limitBottomRight.y()){
            nodeSecond->setPos(nodeSecond->pos().x(), limitBottomRight.y());
        }
        if(event.y() > limitTopLeft.y() && event.y() > limitBottomRight.y()){
            nodeSecond->setPos(nodeSecond->pos().x(), limitBottomRight.y());
        }

        /* Comprobamos qué tipo de roi vamos a dibujar */
        if (nodeFirst->pos().x() < event.x() && nodeFirst->pos().y() < event.y()) {/* ROI TIPO 1 */
            textRoi->setPos(nodeFirst->pos().x() - ((textRoi->boundingRect().width()+2))*m_dCurrentScale, nodeFirst->pos().y() - ((textRoi->boundingRect().height()+2))*m_dCurrentScale);
        } else if (nodeFirst->pos().x() < event.x() && nodeFirst->pos().y() > event.y()) {/* ROI TIPO 2 */
            textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
        } else if (nodeFirst->pos().x() > event.x() && nodeFirst->pos().y() > event.y()) {/* ROI TIPO 3 */
            textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
        } else if (nodeFirst->pos().x() > event.x() && nodeFirst->pos().y() < event.y()) {/* ROI TIPO 4 */
            textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
        }

        graphRect->resetTransform();
        graphRect->setPos(nodeFirst->pos().x(),nodeFirst->pos().y());
        graphRect->setTransformOriginPoint((nodeSecond->pos().x() - nodeFirst->pos().x())/2, (nodeSecond->pos().y() - nodeFirst->pos().y())/2);
        graphRect->setRotation(180);
        graphRect->setRect(0,0, nodeSecond->pos().x() - nodeFirst->pos().x(), nodeSecond->pos().y() - nodeFirst->pos().y());
        punto.setX(nodeFirst->pos().x());
        punto.setY(nodeFirst->pos().y());

//        graphRect->setTransformOriginPoint((nodeSecond->pos().x() - nodeFirst->pos().x())/2, (nodeSecond->pos().y() - nodeFirst->pos().y())/2);
//        graphRect->setRotation(180);
//        graphRect->setRect(0,0, nodeSecond->pos().x() - nodeFirst->pos().x(), nodeSecond->pos().y() - nodeFirst->pos().y());
    } else{
        if(nodeFirst->isSelected() && !m_bSelected){
            /* 1. Seleccionamos el nodo con el que vamos a trabajar y asignamos posicion */
            nodeFirst->setCursor(Qt::ClosedHandCursor);
            if(event.x() < limitTopLeft.x()){
                nodeFirst->setPos(limitTopLeft.x(), event.y());
            }
            if(event.x() > limitBottomRight.x()){
                nodeFirst->setPos(limitBottomRight.x(), event.y());
            }
            if(event.x() > limitTopLeft.x() && event.x() < limitBottomRight.x()) {
                nodeFirst->setPos(event.x(), event.y());
            }

            if(event.y() < limitTopLeft.y()){
                nodeFirst->setPos(nodeFirst->pos().x(), limitTopLeft.y());
            }
            if(event.y() > limitBottomRight.y()){
                nodeFirst->setPos(nodeFirst->pos().x(), limitBottomRight.y());
            }
            if(event.y() > limitTopLeft.y() && event.y() > limitBottomRight.y()){
                nodeFirst->setPos(nodeFirst->pos().x(), limitBottomRight.y());
            }

            /* 2. Dibujamos el rectángulo con los nuevos datos */
//            graphRect->setRect(globalIncX, globalIncY, nodeSecond->pos().x() - nodeFirst->pos().x(), nodeSecond->pos().y() - nodeFirst->pos().y());

            /* 3. Colocamos el texto */
            if (nodeSecond->pos().x() > nodeFirst->pos().x() && nodeSecond->pos().y() > nodeFirst->pos().y()) {/* ROI TIPO 1 */
                textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
            } else if (nodeSecond->pos().x() > nodeFirst->pos().x() && nodeSecond->pos().y() < nodeFirst->pos().y()) {/* ROI TIPO 2 */
                textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
            } else if (nodeSecond->pos().x() < nodeFirst->pos().x() && nodeSecond->pos().y() < nodeFirst->pos().y()) {/* ROI TIPO 3 */
                textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
            } else if (nodeSecond->pos().x() < nodeFirst->pos().x() && nodeSecond->pos().y() > nodeFirst->pos().y()) {/* ROI TIPO 4 */
                textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
            }
        }
        if(nodeSecond->isSelected() && !m_bSelected){
            /* 1. Seleccionamos el nodo con el que vamos a trabajar y asignamos posicion */
            nodeSecond->setCursor(Qt::ClosedHandCursor);
            if(event.x() < limitTopLeft.x()){
                nodeSecond->setPos(limitTopLeft.x(), event.y());
            }
            if(event.x() > limitBottomRight.x()){
                nodeSecond->setPos(limitBottomRight.x(), event.y());
            }
            if(event.x() > limitTopLeft.x() && event.x() < limitBottomRight.x()) {
                nodeSecond->setPos(event.x(), event.y());
            }

            if(event.y() < limitTopLeft.y()){
                nodeSecond->setPos(nodeSecond->pos().x(), limitTopLeft.y());
            }
            if(event.y() > limitBottomRight.y()){
                nodeSecond->setPos(nodeSecond->pos().x(), limitBottomRight.y());
            }
            if(event.y() > limitTopLeft.y() && event.y() > limitBottomRight.y()){
                nodeSecond->setPos(nodeSecond->pos().x(), limitBottomRight.y());
            }


            /* 2. Tranformamos el rectangulo y colocamos el texto */
//            graphRect->resetTransform();
//            graphRect->setPos(nodeFirst->pos().x(),nodeFirst->pos().y());
//            graphRect->setTransformOriginPoint((nodeSecond->pos().x() - nodeFirst->pos().x())/2, (nodeSecond->pos().y() - nodeFirst->pos().y())/2);
//            graphRect->setRotation(180);
//            graphRect->setRect(0,0, nodeSecond->pos().<x() - nodeFirst->pos().x(), nodeSecond->pos().y() - nodeFirst->pos().y());
//            punto.setX(nodeFirst->pos().x());
//            punto.setY(nodeFirst->pos().y());
//            globalIncX = punto.x()-nodeFirst->pos().x();
//            globalIncY = punto.y()-nodeFirst->pos().y();
//            graphRect->setRect(globalIncX, globalIncY, nodeSecond->pos().x()-nodeFirst->pos().x(), nodeSecond->pos().y()-nodeFirst->pos().y());
            //graphRect->setTransformOriginPoint((nodeSecond->pos().x() - nodeFirst->pos().x())/2, (nodeSecond->pos().y() - nodeFirst->pos().y())/2);
            //graphRect->setRotation(180);
            /* Si quiero convertirla en una ROI TIPO 1 */
            if (nodeSecond->pos().x() > nodeFirst->pos().x() && nodeSecond->pos().y() > nodeFirst->pos().y()) {
                textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
            }
            /* Si quiero convertirla en una ROI TIPO 2 */
            else if (nodeSecond->pos().x() > nodeFirst->pos().x() && nodeSecond->pos().y() < nodeFirst->pos().y()) {
                textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
            }
            /* Si quiero convertirla en una ROI TIPO 3 */
            else if (nodeSecond->pos().x() < nodeFirst->pos().x() && nodeSecond->pos().y() < nodeFirst->pos().y()) {
                textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
            }
            /* Si quiero convertirla en una ROI TIPO 4 */
            else if (nodeSecond->pos().x() < nodeFirst->pos().x() && nodeSecond->pos().y() > nodeFirst->pos().y()) {
                textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
            }

            /* Dibujamos el rectángulo con los nuevos datos */
//            globalIncX = punto.x()-nodeFirst->pos().x();
//            globalIncY = punto.y()-nodeFirst->pos().y();
//            graphRect->setRect(globalIncX, globalIncY, nodeSecond->pos().x()-nodeFirst->pos().x(), nodeSecond->pos().y()-nodeFirst->pos().y());
        }
        if(m_bSelected){
            nodeFirst->setCursor(Qt::ClosedHandCursor);
            nodeSecond->setCursor(Qt::ClosedHandCursor);
            textRoi->setCursor(Qt::ClosedHandCursor);
            graphRect->setCursor(Qt::ClosedHandCursor);

            if(nodeFirst->pos().x() < limitTopLeft.x()){
                nodeFirst->setPos(limitTopLeft.x(), nodeFirst->pos().y());
            }
            if(nodeFirst->pos().x() > limitBottomRight.x()){
                nodeFirst->setPos(limitBottomRight.x(), nodeFirst->pos().y());
            }

            if(nodeFirst->pos().y() < limitTopLeft.y()){
                nodeFirst->setPos(nodeFirst->pos().x(), limitTopLeft.y());
            }
            if(nodeFirst->pos().y() > limitBottomRight.y()){
                nodeFirst->setPos(nodeFirst->pos().x(), limitBottomRight.y());
            }

            if(nodeSecond->pos().x() < limitTopLeft.x()){
                nodeSecond->setPos(limitTopLeft.x(), nodeSecond->pos().y());
            }
            if(nodeSecond->pos().x() > limitBottomRight.x()){
                nodeSecond->setPos(limitBottomRight.x(), nodeSecond->pos().y());
            }

            if(nodeSecond->pos().y() < limitTopLeft.y()){
                nodeSecond->setPos(nodeSecond->pos().x(), limitTopLeft.y());
            }
            if(nodeSecond->pos().y() > limitBottomRight.y()){
                nodeSecond->setPos(nodeSecond->pos().x(), limitBottomRight.y());
            }

            /* Si quiero convertirla en una ROI TIPO 1 */
            if (nodeSecond->pos().x() > nodeFirst->pos().x() && nodeSecond->pos().y() > nodeFirst->pos().y()) {
                textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
            }
            /* Si quiero convertirla en una ROI TIPO 2 */
            else if (nodeSecond->pos().x() > nodeFirst->pos().x() && nodeSecond->pos().y() < nodeFirst->pos().y()) {
                textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
            }
            /* Si quiero convertirla en una ROI TIPO 3 */
            else if (nodeSecond->pos().x() < nodeFirst->pos().x() && nodeSecond->pos().y() < nodeFirst->pos().y()) {
                textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
            }
            /* Si quiero convertirla en una ROI TIPO 4 */
            else if (nodeSecond->pos().x() < nodeFirst->pos().x() && nodeSecond->pos().y() > nodeFirst->pos().y()) {
                textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
            }
        }
        graphRect->resetTransform();
        graphRect->setPos(nodeFirst->pos().x(),nodeFirst->pos().y());
        graphRect->setTransformOriginPoint((nodeSecond->pos().x() - nodeFirst->pos().x())/2, (nodeSecond->pos().y() - nodeFirst->pos().y())/2);
        graphRect->setRotation(180);
        graphRect->setRect(0,0, nodeSecond->pos().x() - nodeFirst->pos().x(), nodeSecond->pos().y() - nodeFirst->pos().y());
//        m_scene->addItem(graphRect);
        punto.setX(nodeFirst->pos().x());
        punto.setY(nodeFirst->pos().y());
    }

    //Radio de los nodos en función de la anchura y altura de las etiquetas.
//    double dRadius = std::max(1.5, std::min(abs(graphRect->rect().width()), abs(graphRect->rect().height()))*0.05);
//    nodeFirst->setNodeRadius(1/dRadius);
//    nodeSecond->setNodeRadius(1/dRadius);
//    m_scene->addItem(graphRect);
//    m_scene->addItem(nodeFirst);
//    m_scene->addItem(nodeSecond);
//    m_scene->addItem(textRoi);
}

RELEASE:

void CRoi::release(QPointF event, QPointF limitTopLeft, QPointF limitBottomRight)
{
    if(!m_bExists && m_bFirstNodeExist){
        if(event.x() < limitTopLeft.x()){
            nodeSecond->setPos(limitTopLeft.x(), event.y());
        }
        if(event.x() > limitBottomRight.x()){
            nodeSecond->setPos(limitBottomRight.x(), event.y());
        }
        if(event.x() > limitTopLeft.x() && event.x() < limitBottomRight.x()) {
            nodeSecond->setPos(event.x(), event.y());
        }

        if(event.y() < limitTopLeft.y()){
            nodeSecond->setPos(nodeSecond->pos().x(), limitTopLeft.y());
        }
        if(event.y() > limitBottomRight.y()){
            nodeSecond->setPos(nodeSecond->pos().x(), limitBottomRight.y());
        }
        if(event.y() > limitTopLeft.y() && event.y() > limitBottomRight.y()){
            nodeSecond->setPos(nodeSecond->pos().x(), limitBottomRight.y());
        }
//        m_scene->addItem(nodeSecond);
        nodeSecond->setCursor(Qt::CrossCursor);

        /* Comprobamos qué tipo de roi vamos a dibujar */
        if (nodeFirst->pos().x() < event.x() && nodeFirst->pos().y() < event.y()) {/* ROI TIPO 1 */
            textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
        } else if (nodeFirst->pos().x() < event.x() && nodeFirst->pos().y() > event.y()) {/* ROI TIPO 2 */
            textRoi->setPos(nodeFirst->pos().x() - (textRoi->boundingRect().width()+2)*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
        } else if (nodeFirst->pos().x() > event.x() && nodeFirst->pos().y() > event.y()) {/* ROI TIPO 3 */
            textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() + 2*m_dCurrentScale);
        } else if (nodeFirst->pos().x() > event.x() && nodeFirst->pos().y() < event.y()) {/* ROI TIPO 4 */
            textRoi->setPos(nodeFirst->pos().x() + 2*m_dCurrentScale, nodeFirst->pos().y() - (textRoi->boundingRect().height()+2)*m_dCurrentScale);
        }

        graphRect->setPen(QPen(QColor(0xFF871B), 1*m_dCurrentScale, Qt::SolidLine));
        graphRect->resetTransform();
        graphRect->setPos(nodeFirst->pos().x(), nodeFirst->pos().y());
        graphRect->setTransformOriginPoint((nodeSecond->pos().x() - nodeFirst->pos().x())/2, (nodeSecond->pos().y() - nodeFirst->pos().y())/2);
        graphRect->setRotation(180);
        graphRect->setRect(0,0, nodeSecond->pos().x() - nodeFirst->pos().x(), nodeSecond->pos().y() - nodeFirst->pos().y());
//        m_scene->addItem(graphRect);

        punto.setX(nodeFirst->pos().x());
        punto.setY(nodeFirst->pos().y());
        m_bExists = true;

    } else{

        if(nodeFirst->pos().x() < limitTopLeft.x()){
            nodeFirst->setPos(limitTopLeft.x(), nodeFirst->pos().y());
        }
        if(nodeFirst->pos().x() > limitBottomRight.x()){
            nodeFirst->setPos(limitBottomRight.x(), nodeFirst->pos().y());
        }

        if(nodeFirst->pos().y() < limitTopLeft.y()){
            nodeFirst->setPos(nodeFirst->pos().x(), limitTopLeft.y());
        }
        if(nodeFirst->pos().y() > limitBottomRight.y()){
            nodeFirst->setPos(nodeFirst->pos().x(), limitBottomRight.y());
        }


        if(nodeSecond->pos().x() < limitTopLeft.x()){
            nodeSecond->setPos(limitTopLeft.x(), nodeSecond->pos().y());
        }
        if(nodeSecond->pos().x() > limitBottomRight.x()){
            nodeSecond->setPos(limitBottomRight.x(), nodeSecond->pos().y());
        }

        if(nodeSecond->pos().y() < limitTopLeft.y()){
            nodeSecond->setPos(nodeSecond->pos().x(), limitTopLeft.y());
        }
        if(nodeSecond->pos().y() > limitBottomRight.y()){
            nodeSecond->setPos(nodeSecond->pos().x(), limitBottomRight.y());
        }



        if(nodeFirst->isSelected() && !m_bSelected){
            nodeFirst->setCursor(Qt::OpenHandCursor);
            nodeFirst->setSelected(false);
        }
        if(nodeSecond->isSelected() && !m_bSelected){
            nodeSecond->setCursor(Qt::CrossCursor);
            nodeSecond->setSelected(false);
        }
        if(m_bSelected){
            nodeFirst->setCursor(Qt::CrossCursor);
            nodeSecond->setCursor(Qt::CrossCursor);
            textRoi->setCursor(Qt::CrossCursor);
            graphRect->setCursor(Qt::CrossCursor);
            /**** Descomentar para deseleccionar al soltar ****/
            //nodeFirst->setSelected(false);
            //nodeSecond->setSelected(false);
            //textRoi->setSelected(false);
            //graphRect->setSelected(false);
        }
        graphRect->resetTransform();
        graphRect->setPos(nodeFirst->pos().x(),nodeFirst->pos().y());
        graphRect->setTransformOriginPoint((nodeSecond->pos().x() - nodeFirst->pos().x())/2, (nodeSecond->pos().y() - nodeFirst->pos().y())/2);
        graphRect->setRotation(180);
        graphRect->setRect(0,0, nodeSecond->pos().x() - nodeFirst->pos().x(), nodeSecond->pos().y() - nodeFirst->pos().y());
//        m_scene->addItem(graphRect);
        punto.setX(nodeFirst->pos().x());
        punto.setY(nodeFirst->pos().y());
    }

    m_scene->addItem(graphRect);
    m_scene->addItem(nodeFirst);
    m_scene->addItem(nodeSecond);
    m_scene->addItem(textRoi);

    calculateVertices();
    //Radio de los nodos en función de la anchura y altura de las etiquetas.
//    double dRadius = std::max(1.5, std::min(abs(graphRect->rect().width()), abs(graphRect->rect().height()))*0.05);
//    nodeFirst->setNodeRadius(1/dRadius);
//    nodeSecond->setNodeRadius(1/dRadius);
}

Sorry @JonB, yes, I use a QGraphicsRectItem

JonB

@ivanicy said in Problem drawing in QGraphicsView:

Sorry @JonB, yes, I use a QGraphicsRectItem

Then I don't know what is causing the artefacts to be left.

ivanicy

I found a solution. It was simple. I had to add scene->update() in move() function to fix it.