当我调整自定义项目时，如何在自定义Qgraphictem中的场景中隐藏子项目

Question

我有一个自定义的QGraphicsItem，我在其中创建了一些项目。调整父级QGraphicsItem大小时，我想隐藏不在父件内的剩余的子项目零件。

#include "mysquare.h"
#include "mysvgitem.h"
#include <QTranslator>
MySquare::MySquare()
        :QGraphicsItem()
{
    myItemRect = QRectF(0, 0, 150, 70); // Default value
    setFlag(ItemIsMovable);
    setFlag(QGraphicsItem::ItemIsSelectable);
    setMyPolygon();//member function
    setFlag(ItemSendsScenePositionChanges, true);
    posXY = new QString(QString::number(this->x()) + ", " +
            QString::number(this->y()));
    itemXY = new QGraphicsTextItem(this);
    itemXY->setPlainText((*posXY));
    itemXY->setTextInteractionFlags(Qt::TextEditorInteraction);
    itemXY->setZValue(2000);
    //text->setHtml("<heloooooooooo>");
    itemXY->setPos(this->x(), this->y());
    this->setCacheMode(QGraphicsItem::DeviceCoordinateCache);
    this->setPos(100, 100);
}

QRectF MySquare::boundingRect() const
{
    return myItemRect;
}

void MySquare::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_UNUSED(widget);
    Q_UNUSED(option);
    QRectF rect = boundingRect();
    QBrush brush(Qt::green);
    QPainterPath path;
    path.addRoundedRect( rect.translated(0.3, 0.3), 5.0, 5.0);
    QFont font;
    //font.setFamily("Armenian (phonetic)");
    font.setPointSize(20);
    //QString mystr = "Partners andnCustomers";
    //path.addText(QPointF(40, 30), font, tr("Partners nand Customers"));
    painter->fillPath(path, Qt::white);
    painter->setPen(Qt::blue);
    //painter->drawText(QRect(105, 55, 115, 35), Qt::AlignLeft, mystr);
    painter->drawText(MyTextRect, Qt::AlignLeft, MyText);
    QPen pen(Qt::black, 1);
    painter->setPen(pen);
    //painter->setBrush(brush);
    painter->setRenderHint(QPainter::Antialiasing); // This is for rectangle alignment
    painter->drawPath(path);
}

void MySquare::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    //Pressed = true;
    //update();
    QString *xy = new QString(QString::number(event->pos().x()) + ", " +
                              QString::number(event->pos().y()));
    itemXY->setPlainText((*xy));
    QPointF p = event->pos();
    QRectF r = sceneBoundingRect(); // Relative to scene
    QPointF tl = mapFromScene(r.topLeft());
    QPointF br = mapFromScene(r.bottomRight());
    if (p.x() <= tl.x() + 10)
    {
        resize_direction_ = rd_left;
        itemXY->setPlainText("rd_left");
    }
    else if (p.x() >= br.x() - 10)
    {
        resize_direction_ = rd_right;
    }
    else if (p.y() <= tl.y() + 10)
    {
        resize_direction_ = rd_top;
    }
    else if (p.y() >= br.y()-10)
    {
        resize_direction_ = rd_bottom;
        qDebug() << "rd_right" ;
    }
    else
    {
        resize_direction_ = rd_none;
    }
    //this->setCursor(Qt::SizeAllCursor);
    QGraphicsItem::mousePressEvent(event);
}

void MySquare::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    //was_moved_ = true;
    if (isSelected())
    {
        // Resize border to mouse position
        QPointF p = event->pos();
        QPointF pp = mapToItem(this, p);
        //QRectF r = rect();
        QRectF r = boundingRect();
        switch (resize_direction_)
        {
            case rd_left:
                r.setLeft(pp.x() + 10);
                prepareGeometryChange();
                myItemRect = r ;
                break;
            case rd_top:
                r.setTop(pp.y());
                prepareGeometryChange();
                myItemRect = r ;
                break;
            case rd_right:
                r.setRight(pp.x());
                prepareGeometryChange();
                myItemRect = r ;
                break;
            case rd_bottom:
                r.setBottom(pp.y());
                prepareGeometryChange();
                myItemRect = r ;
                break;
            default:
                QGraphicsItem::mouseMoveEvent(event);
                qDebug() << " default moving ";
                this->setCursor(Qt::ArrowCursor);
                break;
        }
        return; //
    }
    QGraphicsItem::mouseMoveEvent(event);
}
void MySquare::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    //Pressed = false;
    //update();
    //emit click();
    qDebug() << sceneBoundingRect();
    QTimer::singleShot(500, this, SIGNAL(click()));
    QGraphicsItem::mouseReleaseEvent(event);
}
QVariant MySquare::itemChange(GraphicsItemChange change, const QVariant &value)
{
    if (change == QGraphicsItem::ItemPositionChange && scene()) {
        foreach (Arrow *arrow, arrows) {
            arrow->updatePosition();
        }
        *posXY = QString::number(this->x()) + ", " +
                                 QString::number(this->y());
        //itemXY->setPlainText((*posXY));
    }
    if (change == QGraphicsItem::ItemOpacityChange) {
        foreach (Arrow *arrow, arrows) {
            arrow->setOpacity(this->opacity());
        }
    }
   return QGraphicsItem::itemChange(change, value);
}
void MySquare::addArrow(Arrow *arrow)
{
    arrows.append(arrow);
}
QPointF MySquare::returnCenter()
{
    QRectF rect = boundingRect();
    qreal width = rect.width();
    qreal height = rect.height();
    QPointF p = QPointF(width/2 + rect.x(), rect.y() + height/2);
    //return p; // Changed for test
    return this->pos() + p; // Changed for test
}

void MySquare::setMyPolygon()
{
    QRectF rec = boundingRect();
    QPolygonF poly ;
    //QPointF p = rec.topLeft();
    poly << rec.topLeft() + this->pos()  << rec.topRight() + this->pos()
         << rec.bottomRight()  + this->pos() << rec.bottomLeft() + this->pos()
         << rec.topLeft() + this->pos();
    myPolygon =  poly;
}

void MySquare::setItemSize(qreal width, qreal height)
{
    myItemRect.setWidth(width);
    myItemRect.setHeight(height);
    update();
}

void MySquare::setSize(QSize size)
{
    prepareGeometryChange();
    myItemRect.setWidth(size.width());
    myItemRect.setHeight(size.height());
}

QSize MySquare::size()
{
    return QSize( myItemRect.width(), myItemRect.height());
}

void MySquare::setImage(const QString& str)
{
    QImage image(QCoreApplication::applicationDirPath() + "/" + str);
    QImage img = image;
    QGraphicsItem *item = new QGraphicsPixmapItem(
                    QPixmap::fromImage(img));
    //item->setSize(size);
    //svg->setMaximumCacheSize(QSize(350, 350));
    Q_ASSERT(!item.isNull());
    item->setParentItem(this);
}
void MySquare::setImage(const QString& str, const QSize size)
{
    QImage image(QCoreApplication::applicationDirPath() + "/" + str);
    QImage img = image.scaled(size);
    /* QGraphicsPixmapItem* item = new QGraphicsPixmapItem(
                    QPixmap::fromImage(image)); */
    QGraphicsItem *item = new QGraphicsPixmapItem(
                    QPixmap::fromImage(img));
    //item->setSize(size);
    //svg->setMaximumCacheSize(QSize(350, 350));
    Q_ASSERT(!item.isNull());
    item->setPos(21, 11);
    item->setParentItem(this);
}

void MySquare::setImage(const QString& str, QRectF rec)
{
    QImage image(QCoreApplication::applicationDirPath() + "/" + str);
    QImage img = image.scaled(QSize(rec.width(), rec.height()));
    /* QGraphicsPixmapItem* item = new QGraphicsPixmapItem(
                    QPixmap::fromImage(image)); */
    QGraphicsItem *item = new QGraphicsPixmapItem(
                    QPixmap::fromImage(img));
    Q_ASSERT(!item.isNull());
    //item->setSize(QSize(rec.width(), rec.height()));
    item->setParentItem(this);
    item->setPos(rec.x(), rec.y());
}

void MySquare::setSvgImage(const QString& str)
{
    QGraphicsItem  *m_svgItem = new QGraphicsSvgItem(
        QCoreApplication::applicationDirPath() + "/" + str);
    Q_ASSERT(!m_svgItem.isNull());
    m_svgItem->setPos(5, 5);
    m_svgItem->setParentItem(this);
}

void MySquare::setSvgImage(const QString& str, QSizeF size)
{
    /* QGraphicsSvgItem  *svg = new QGraphicsSvgItem(
            QCoreApplication::applicationDirPath() + "/" + str); */
    MySvgItem  *svg = new MySvgItem(
            QCoreApplication::applicationDirPath() + "/" + str);
    svg->setSize(size);
    //svg->setMaximumCacheSize(QSize(350, 350));
    Q_ASSERT(!svg.isNull());
    QGraphicsItem  *m_svgItem = svg;
    //m_svgItem->setPos(5, 5);
    m_svgItem->setParentItem(this);
    m_svgItem->setZValue(-1000);
}

void MySquare::setSvgImage(const QString& str, QRectF rec)
{
    MySvgItem  *svg = new MySvgItem(
            QCoreApplication::applicationDirPath() + "/" + str);
    Q_ASSERT(!svg.isNull());
    svg->setSize(QSize(rec.width(), rec.height()));
    QGraphicsItem  *m_svgItem = svg;
    m_svgItem->setParentItem(this);
    m_svgItem->setPos(rec.x(), rec.y());
    m_svgItem->setZValue(-1000);
}

void MySquare::setText(const QString& str, QRectF rec)
{
    QGraphicsTextItem *text = new QGraphicsTextItem(this);
    //text->setTextInteractionFlags(Qt::TextEditorInteraction);
    text->setHtml(str);
    text->setPos(rec.x(), rec.y());
}

MySquare::~MySquare()
{
    for (int i=0; i< arrows.count(); i++)
    {
        if (arrows.at(i) == NULL){
            delete arrows.at(i);
        }
    }
}

Answer 1

刚刚添加了setFlag(qgraphictem :: itemclipschildrentoshape，true(;