C++ QQuickItem::height方法代码示例

void tst_applicationwindow::implicitFill()
{
    QQmlEngine engine;
    QQmlComponent component(&engine);
    component.loadUrl(testFileUrl("fill.qml"));
    QObject* created = component.create();
    QScopedPointer<QObject> cleanup(created);
    QVERIFY(created);

    QQuickWindow* window = qobject_cast<QQuickWindow*>(created);
    QVERIFY(window);
    QVERIFY(!window->isVisible());
    QCOMPARE(window->width(), 400);
    QCOMPARE(window->height(), 400);

    window->show();
    QVERIFY(QTest::qWaitForWindowActive(window));

    QQuickItem *stackView = window->property("stackView").value<QQuickItem*>();
    QVERIFY(stackView);
    QCOMPARE(stackView->width(), 400.0);
    QCOMPARE(stackView->height(), 400.0);

    QQuickItem *nextItem = window->property("nextItem").value<QQuickItem*>();
    QVERIFY(nextItem);

    QVERIFY(QMetaObject::invokeMethod(window, "pushNextItem"));
    QCOMPARE(nextItem->width(), 400.0);
    QCOMPARE(nextItem->height(), 400.0);
}

QQuickItem *GlobalFunctions::itemAt(QQuickItem* parent, int x, int y, QJSValue matcher)
{
    if (!parent) return nullptr;
    QList<QQuickItem *> children = QQuickItemPrivate::get(parent)->paintOrderChildItems();

    for (int i = children.count() - 1; i >= 0; --i) {
        QQuickItem *child = children.at(i);

        // Map coordinates to the child element's coordinate space
        QPointF point = parent->mapToItem(child, QPointF(x, y));
        if (child->isVisible() && point.x() >= 0
                && child->width() >= point.x()
                && point.y() >= 0
                && child->height() >= point.y()) {
            if (!matcher.isCallable()) return child;

            QQmlEngine* engine = qmlEngine(child);
            if (!engine) return child;

            QJSValue newObj = engine->newQObject(child);
            if (matcher.call(QJSValueList() << newObj).toBool()) {
                return child;
            }
        }
    }
    return nullptr;
}

void Tracking::updatePositionMarker()
{
    if ( m_marbleQuickItem && m_positionMarker && m_positionMarkerType == Circle ) {
        Coordinate* position = 0;
        bool visible = (m_marbleQuickItem->model()->planetId() == QLatin1String("earth"));
        if ( m_positionSource && m_positionSource->hasPosition() ) {
            position = m_positionSource->position();
        } else if ( hasLastKnownPosition() ) {
            position = lastKnownPosition();
        } else {
            visible = false;
        }

        qreal x(0), y(0);
        if ( position ) {
            Marble::GeoDataCoordinates const pos( position->longitude(), position->latitude(), 0.0, GeoDataCoordinates::Degree );
            visible = visible && m_marbleQuickItem->map()->viewport()->screenCoordinates( pos.longitude(), pos.latitude(), x, y );
            QQuickItem* item = qobject_cast<QQuickItem*>( m_positionMarker );
            if ( item ) {
                item->setVisible( visible );
                if ( visible ) {
                    item->setX( x - item->width() / 2.0 );
                    item->setY( y - item->height() / 2.0 );
                }
            }
        }
    } else if ( m_positionMarkerType != Circle ) {
        QQuickItem* item = qobject_cast<QQuickItem*>( m_positionMarker );
        if ( item ) {
            item->setVisible( false );
        }
    }
}

void TestSimpleQmlLoad::loadScript1()
{
    QQmlEngine *engine = new QQmlEngine;
    const QString TEST_FILE(":/testqml/testscript1.qml");
    QQmlComponent* component = load(engine, TEST_FILE);
    QVERIFY(component);

    QObject *myObject = component->create();
    QQuickItem *item = qobject_cast<QQuickItem*>(myObject);
    int width = item->width();
    QVERIFY(width == 100);
    int height = item->height();
    QVERIFY(height == 201);
    item->setWidth(15);
    height = item->height();
    QVERIFY(height == 31);
    delete component;
    delete engine;
}

void StretchColumn::layoutChildrenWithDefaultSize() {
	//static int count = 0;
	//qDebug() << "Column Default Size" << ++count;
    Q_ASSERT(m_defaultSize != 0);

	const QList<QQuickItem *> childrenList = childItems();
	if (childrenList.isEmpty()) return;

    const int contentWidth = width() - m_leftMargin - m_rightMargin;
    qreal currY = 0;
    for (QList<QQuickItem *>::const_iterator it = childrenList.constBegin(); it != childrenList.constEnd(); ++it) {
		QQuickItem* child = (*it);
		if (child == Q_NULLPTR || !child->isVisible()) {
			continue;
		}

		// add spacing if it is not the first item:
		if (currY > 0) {
			currY += m_spacing;
		}
		if (currY != child->y()) child->setY(currY);
		// check if item has a stretch proportion set:
		if (child->implicitHeight() < 0) {
			// yes -> set it to default size multiplied by relative size:
            qreal newHeight = m_defaultSize * child->implicitHeight() * -1;
            if (newHeight != child->height()) child->setHeight(newHeight);
		}
		// set width of all items to fill the layout:
        if (m_leftMargin != child->x()) child->setX(m_leftMargin);
		if (contentWidth != child->width()) child->setWidth(contentWidth);
		currY += child->height();
	}

	// set implicit size to fit all items:
	if (currY != implicitHeight()) setImplicitHeight(currY);
}

void QQuickStretchColumnContainer::updatePolish (void) {
    const QList<QQuickItem *> childrenList = childItems ();
    /// find items and stretchers
    qreal tmpW = 0;
    qreal tmpH = 0;
    int nbItems   = 0;
    int nbStretch = 0;
    for (QList<QQuickItem *>::const_iterator it = childrenList.constBegin (); it != childrenList.constEnd (); it++) {
        QQuickItem * child = (* it);
        if (child != Q_NULLPTR && !child->inherits ("QQuickRepeater") && child->isVisible ()) {
            if (child->implicitWidth () > tmpW) {
                tmpW = child->implicitWidth ();
            }
            if (child->implicitHeight () >= 0) {
                tmpH += child->implicitHeight ();
            }
            else {
                nbStretch++;
            }
            nbItems++;
        }
    }
    /// resize layout
    if (nbItems > 1) {
        tmpH += (m_spacing * (nbItems -1));
    }
    setImplicitWidth  (tmpW);
    setImplicitHeight (tmpH);
    const qreal layoutWidth  = width  ();
    const qreal layoutHeight = height ();
    const qreal autoSize = (nbStretch > 0 ? (layoutHeight - tmpH) / qreal (nbStretch) : 0);
    /// position children
    int currY = 0;
    for (QList<QQuickItem *>::const_iterator it = childrenList.constBegin (); it != childrenList.constEnd (); it++) {
        QQuickItem * child = (* it);
        if (child != Q_NULLPTR && !child->inherits ("QQuickRepeater") && child->isVisible ()) {
            if (currY) {
                currY += m_spacing;
            }
            child->setY (currY);
            child->setWidth (layoutWidth);
            child->setHeight (child->implicitHeight () >= 0 ? child->implicitHeight () : autoSize);
            currY += child->height ();
        }
    }
}

/*!
  Traverse QObject based items.
*/
void SceneGraphTraverse::traverseObject(TasObject* objectInfo, QObject* object, TasCommand* command)
{
    Q_UNUSED(command);

    QQuickItem* item = qobject_cast<QQuickItem*>(object);

    if (item) {
        QQmlContext* context = QQmlEngine::contextForObject(object);

        if (context) {
            QString name = context->nameForObject(object);
            objectInfo->addAttribute("QML_ID", name);
        }

#ifdef USE_QTQML_PRIVATE_HEADERS
        addTypeInfo(item, objectInfo);
#endif

        mTraverseUtils->addObjectDetails(objectInfo, object);

        objectInfo->addAttribute("objectType", TYPE_QSCENEGRAPH);

        QPointF point = item->mapToScene(QPoint());

        // needed for visualizer
        objectInfo->addAttribute("x", (int)point.x());
        objectInfo->addAttribute("y", (int)point.y());
        objectInfo->addAttribute("x_absolute", (int)point.x());
        objectInfo->addAttribute("y_absolute", (int)point.y());


        objectInfo->addAttribute("x_relative", item->x());
        objectInfo->addAttribute("y_relative", item->y());

        // TODO already included?
        objectInfo->addAttribute("width", item->width());
        objectInfo->addAttribute("height", item->height());
    }
}

void StretchRow::layoutChildrenWithProportions() {
	//static int count = 0;
	//qDebug() << "Row Proportions" << ++count;
	const QList<QQuickItem*> childrenList = childItems();
	if (childrenList.isEmpty()) return;
	if (width() <= 0) return;
	int visibleItems = 0;
    qreal availableForStretch = width() - m_leftMargin - m_rightMargin;
	qreal sumStretchProportions = 0.0;

	// iterate over all children and calculate available size to stretch items:
    for (QList<QQuickItem *>::const_iterator it = childrenList.constBegin(); it != childrenList.constEnd(); ++it) {
		QQuickItem* child = (*it);
		if (child == Q_NULLPTR || !child->isVisible()) {
			continue;
		}

		if (child->implicitWidth() >= 0) {
			// no stretch proportion set -> leave size and remove it from available space:
			availableForStretch -= child->width();
		} else {
			// a stretch proportion is set -> add it to sum:
			sumStretchProportions += (child->implicitWidth() * -1);
		}
		visibleItems++;
	}
	// remove spacing from available space:
	availableForStretch -= m_spacing * (visibleItems - 1);

    const int layoutHeight = height();
    QPointer<QQuickItem> lastStretchItem = nullptr;
    qreal currX = m_leftMargin;
    for (QList<QQuickItem *>::const_iterator it = childrenList.constBegin(); it != childrenList.constEnd(); ++it) {
		QQuickItem* child = (*it);
		if (child == Q_NULLPTR || !child->isVisible()) {
			continue;
		}

		// add spacing if it is not the first item:
		if (currX > 0) {
			currX += m_spacing;
        }
        if (currX != child->x()) child->setX(currX);
		// check if item has a stretch proportion set (if not do nothing):
		if (child->implicitWidth() < 0) {
			// get the stretch proportion:
			qreal stretchProportion = (child->implicitWidth() * -1);
			// calculate the relation of the total space available for stretched items
			// that this item will use:
			// (sumStretchProportion can not be 0 (in divison) because if this "if" is executed,
			// there has been at least one item with a stretch proportion set)
			qreal relationOfSpaceAvailableForStretch = stretchProportion / sumStretchProportions;
            qreal newWidth = qRound(availableForStretch * relationOfSpaceAvailableForStretch);
            if (newWidth != child->width()) child->setWidth(newWidth);
			lastStretchItem = child;
		}
        // set height of all items to fill the layout:
        if (layoutHeight != child->height()) child->setHeight(layoutHeight);
		currX += child->width();
	}
	currX += m_rightMargin;

	// check if last item fills whole remaining space in this layout:
	// (can happen because of rounding mistakes)
	if (lastStretchItem) {
		double pxMissing = width() - currX;
        if (pxMissing > 0.0001) {
            // qInfo() << "StretchRow layout mismatch: " << pxMissing;
			// it does not -> adjust it:
			lastStretchItem->setWidth(lastStretchItem->width() + pxMissing);
		}
	}
}

void QQuickComponentsLinearLayout::reconfigureLayout()
{
    if (!isComponentComplete())
        return;

    const int count = m_items.count();

    if (count == 0)
        return;

    qreal totalSpacing = 0;
    qreal totalSizeHint = 0;
    qreal totalMinimumSize = 0;
    qreal totalMaximumSize = 0;

    QVector<QQuickComponentsLayoutInfo> itemData;

    for (int i = 0; i < count; i++) {
        QQuickItem *item = m_items.at(i);
        QObject *attached = qmlAttachedPropertiesObject<QQuickComponentsLayout>(item);
        QQuickComponentsLayoutAttached *info = static_cast<QQuickComponentsLayoutAttached *>(attached);

        QQuickComponentsLayoutInfo data;

        if (m_orientation == Horizontal) {
            data.sizeHint = item->implicitWidth();
            data.minimumSize = info->minimumWidth();
            data.maximumSize = info->maximumWidth();
            data.expansive = (info->horizontalSizePolicy() == QQuickComponentsLayout::Expanding);
            data.stretch = info->horizontalSizePolicy() == Expanding ? 1.0 : 0;
        } else {
            data.sizeHint = item->implicitHeight();
            data.minimumSize = info->minimumHeight();
            data.maximumSize = info->maximumHeight();
            data.expansive = (info->verticalSizePolicy() == QQuickComponentsLayout::Expanding);
            data.stretch = info->verticalSizePolicy() == Expanding ? 1.0 : 0;
        }

        itemData.append(data);

        // sum
        totalSizeHint += data.sizeHint;
        totalMinimumSize += data.minimumSize;
        totalMaximumSize += data.maximumSize;

        // don't count last spacing
        if (i < count - 1)
            totalSpacing += data.spacing + m_spacing;
    }

    if (m_orientation == Horizontal) {
        qDeclarativeLayoutCalculate(itemData, 0, count, 0, width(), m_spacing);

        for (int i = 0; i < count; i++) {
            QQuickItem *item = m_items.at(i);
            const QQuickComponentsLayoutInfo &data = itemData.at(i);

            item->setX(data.pos);
            item->setY(height()/2 - item->height()/2);
            item->setWidth(data.size);
        }
    } else {
        qDeclarativeLayoutCalculate(itemData, 0, count, 0, height(), m_spacing);

        for (int i = 0; i < count; i++) {
            QQuickItem *item = m_items.at(i);
            const QQuickComponentsLayoutInfo &data = itemData.at(i);

            item->setY(data.pos);
            item->setX(width()/2 - item->width()/2);
            item->setHeight(data.size);
        }
    }

    // propagate hints to upper levels
    QObject *attached = qmlAttachedPropertiesObject<QQuickComponentsLayout>(this);
    QQuickComponentsLayoutAttached *info = static_cast<QQuickComponentsLayoutAttached *>(attached);

    if (m_orientation == Horizontal) {
        setImplicitWidth(totalSizeHint);
        info->setMinimumWidth(totalMinimumSize + totalSpacing);
        info->setMaximumWidth(totalMaximumSize + totalSpacing);
    } else {
        setImplicitHeight(totalSizeHint);
        info->setMinimumHeight(totalMinimumSize + totalSpacing);
        info->setMaximumHeight(totalMaximumSize + totalSpacing);
    }
}

//.........这里部分代码省略.........
                }

                qreal scale = 1;
                qreal rotation = 0;
                bool isRotate = (transform.type() == QTransform::TxRotate) || (transform.m11() < 0);
                if (ok && !isRotate) {
                    if (transform.m11() == transform.m22())
                        scale = transform.m11();
                    else {
                        qmlInfo(this) << QQuickParentAnimation::tr("Unable to preserve appearance under non-uniform scale");
                        ok = false;
                    }
                } else if (ok && isRotate) {
                    if (transform.m11() == transform.m22())
                        scale = qSqrt(transform.m11()*transform.m11() + transform.m12()*transform.m12());
                    else {
                        qmlInfo(this) << QQuickParentAnimation::tr("Unable to preserve appearance under non-uniform scale");
                        ok = false;
                    }

                    if (scale != 0)
                        rotation = atan2(transform.m12()/scale, transform.m11()/scale) * 180/M_PI;
                    else {
                        qmlInfo(this) << QQuickParentAnimation::tr("Unable to preserve appearance under scale of 0");
                        ok = false;
                    }
                }

                const QPointF &point = transform.map(QPointF(xAction.toValue.toReal(),yAction.toValue.toReal()));
                qreal x = point.x();
                qreal y = point.y();
                if (ok && target->transformOrigin() != QQuickItem::TopLeft) {
                    qreal w = target->width();
                    qreal h = target->height();
                    if (pc->widthIsSet() && i < actions.size() - 1)
                        w = actions[++i].toValue.toReal();
                    if (pc->heightIsSet() && i < actions.size() - 1)
                        h = actions[++i].toValue.toReal();
                    const QPointF &transformOrigin
                            = d->computeTransformOrigin(target->transformOrigin(), w,h);
                    qreal tempxt = transformOrigin.x();
                    qreal tempyt = transformOrigin.y();
                    QTransform t;
                    t.translate(-tempxt, -tempyt);
                    t.rotate(rotation);
                    t.scale(scale, scale);
                    t.translate(tempxt, tempyt);
                    const QPointF &offset = t.map(QPointF(0,0));
                    x += offset.x();
                    y += offset.y();
                }

                if (ok) {
                    //qDebug() << x << y << rotation << scale;
                    xAction.toValue = x;
                    yAction.toValue = y;
                    sAction.toValue = sAction.toValue.toReal() * scale;
                    rAction.toValue = rAction.toValue.toReal() + rotation;
                }
            }
        }
    }

    if (data->actions.count()) {
        QSequentialAnimationGroupJob *topLevelGroup = new QSequentialAnimationGroupJob;
        QActionAnimation *viaAction = d->via ? new QActionAnimation : 0;

void ScreenshotService::getScreenshot(TasCommandModel& model, TasResponse& response)
{
    QListIterator<TasTarget*> i(model.targetList());
    QString errorMsg = PARSE_ERROR;
    QImage screenshot;
    QString pictureFormat = "PNG";
    while (i.hasNext()) {
        TasTarget* commandTarget = i.next();
        QString targetId = commandTarget->id();
        QString targetType = commandTarget->type();
        TasCommand* command = commandTarget->findCommand("Screenshot");

        // are required for command completion
        if (targetId.isEmpty() || targetType.isEmpty() || !command) {
            continue;
        }

        if (!command->parameter("format").isEmpty()) {
            pictureFormat = command->parameter("format");
        }

        if (!isFormatSupported(pictureFormat)) {
            errorMsg = "Given format " + pictureFormat + "is not supported. Supported formats are: PNG, JPEG and BMP.";
            break;
        }

        bool draw = (command->parameter("draw") == "true");

        QWidget* widget = 0;
        QQuickWindow* qtQuickWindow = 0;
        WId winId = 0;
        QRect rect(0,0,-1,-1);

        errorMsg = "Taking screenshot failed!";

        if (targetType == TYPE_GRAPHICS_VIEW) {
            //TasLogger::logger()->debug("TYPE_GRAPHICS_VIEW Target id:" + targetId);
            QGraphicsItem* item = findGraphicsItem(targetId);

            if (item) {
                QGraphicsView* view = getViewForItem(item);
                if(view) {
                    ItemLocationDetails locationDetails = TestabilityUtils::getItemLocationDetails(item);
                    rect = QRect(locationDetails.windowPoint.x(),
                                 locationDetails.windowPoint.y(),
                                 locationDetails.width,
                                 locationDetails.height);

                    if (draw) {
                        widget = view->window();
                    } else {
                        winId = view->window()->winId();
                    }
                } else {
                    errorMsg = "Could not find a GraphicsView for the GraphicsItem!";
                }
            } else {
                errorMsg = "Could not find the GraphicsItem!";
            }
        } else if (targetType == TYPE_STANDARD_VIEW) {
            //TasLogger::logger()->debug("TYPE_STANDARD_VIEW about to find widget Target id:" + targetId);
            widget = findWidget(targetId);

            if (widget) {
                if ((widget->isWindow() && !draw) || widget->inherits("QDesktopWidget")) {
                    winId = widget->winId();
                    widget = 0;
                } else if (!draw) {
                    QPoint point = widget->mapToGlobal(QPoint(0,0));
                    QPoint windowPoint = widget->window()->mapFromGlobal(point);

                    rect = QRect(windowPoint.x(),
                                 windowPoint.y(),
                                 widget->rect().width(),
                                 widget->rect().width());
                    winId = widget->window()->winId();
                    widget = 0;
                }
            } else {
                TasLogger::logger()->debug("ScreenshotService::executeService application has no visible ui!");
                errorMsg = "Application has no visible ui!";
            }
        } else if (targetType == TYPE_QSCENEGRAPH) {
            QQuickItem* item = TestabilityUtils::findQuickItem(targetId);

            if (item) {
                QPointF offset = item->mapToScene(QPointF(0,0));
                rect = QRect(-offset.x(), -offset.y(), item->width(), item->height());
                qtQuickWindow = item->window();
            }
        } else {
            //TasLogger::logger()->debug("TYPE_APPLICATION_VIEW about to find application window Target id:" + targetId);
            widget = getApplicationWidget();

            if (!widget) {
                QWindow *window = getApplicationWindow();
                //in case no window false, return the desktop
                qtQuickWindow = qobject_cast<QQuickWindow *>(window);

                if (!window) {
//.........这里部分代码省略.........

void tst_qquickwidget::resizemodeitem()
{
    QWidget window;
    window.setGeometry(0, 0, 400, 400);

    QScopedPointer<QQuickWidget> view(new QQuickWidget);
    view->setParent(&window);
    view->setResizeMode(QQuickWidget::SizeRootObjectToView);
    QCOMPARE(QSize(0,0), view->initialSize());
    view->setSource(testFileUrl("resizemodeitem.qml"));
    QQuickItem* item = qobject_cast<QQuickItem*>(view->rootObject());
    QVERIFY(item);
    window.show();

    view->showNormal();
    // initial size from root object
    QCOMPARE(item->width(), 200.0);
    QCOMPARE(item->height(), 200.0);
    QCOMPARE(view->size(), QSize(200, 200));
    QCOMPARE(view->size(), view->sizeHint());
    QCOMPARE(view->size(), view->initialSize());

    // size update from view
    view->resize(QSize(80,100));

    QTRY_COMPARE(item->width(), 80.0);
    QCOMPARE(item->height(), 100.0);
    QCOMPARE(view->size(), QSize(80, 100));
    QCOMPARE(view->size(), view->sizeHint());

    view->setResizeMode(QQuickWidget::SizeViewToRootObject);

    // size update from view disabled
    view->resize(QSize(60,80));
    QCOMPARE(item->width(), 80.0);
    QCOMPARE(item->height(), 100.0);
    QTRY_COMPARE(view->size(), QSize(60, 80));

    // size update from root object
    item->setWidth(250);
    item->setHeight(350);
    QCOMPARE(item->width(), 250.0);
    QCOMPARE(item->height(), 350.0);
    QTRY_COMPARE(view->size(), QSize(250, 350));
    QCOMPARE(view->size(), QSize(250, 350));
    QCOMPARE(view->size(), view->sizeHint());

    // reset window
    window.hide();
    view.reset(new QQuickWidget(&window));
    view->setResizeMode(QQuickWidget::SizeViewToRootObject);
    view->setSource(testFileUrl("resizemodeitem.qml"));
    item = qobject_cast<QQuickItem*>(view->rootObject());
    QVERIFY(item);
    window.show();

    view->showNormal();

    // initial size for root object
    QCOMPARE(item->width(), 200.0);
    QCOMPARE(item->height(), 200.0);
    QCOMPARE(view->size(), view->sizeHint());
    QCOMPARE(view->size(), view->initialSize());

    // size update from root object
    item->setWidth(80);
    item->setHeight(100);
    QCOMPARE(item->width(), 80.0);
    QCOMPARE(item->height(), 100.0);
    QTRY_COMPARE(view->size(), QSize(80, 100));
    QCOMPARE(view->size(), view->sizeHint());

    // size update from root object disabled
    view->setResizeMode(QQuickWidget::SizeRootObjectToView);
    item->setWidth(60);
    item->setHeight(80);
    QCOMPARE(view->width(), 80);
    QCOMPARE(view->height(), 100);
    QCOMPARE(QSize(item->width(), item->height()), view->sizeHint());

    // size update from view
    view->resize(QSize(200,300));
    QTRY_COMPARE(item->width(), 200.0);
    QCOMPARE(item->height(), 300.0);
    QCOMPARE(view->size(), QSize(200, 300));
    QCOMPARE(view->size(), view->sizeHint());

    window.hide();

    // if we set a specific size for the view then it should keep that size
    // for SizeRootObjectToView mode.
    view.reset(new QQuickWidget(&window));
    view->resize(300, 300);
    view->setResizeMode(QQuickWidget::SizeRootObjectToView);
    QCOMPARE(QSize(0,0), view->initialSize());
    view->setSource(testFileUrl("resizemodeitem.qml"));
    view->resize(300, 300);
    item = qobject_cast<QQuickItem*>(view->rootObject());
    QVERIFY(item);
    window.show();
//.........这里部分代码省略.........

QSGNode* NodeConnectionLines::updatePaintNode(QSGNode* oldNode, UpdatePaintNodeData*) {
    if (!m_nodeObject) return nullptr;
    const QVector<QPointer<NodeBase>>& connectedNodes = m_nodeObject->getConnectedNodes();
    int connectionCount = connectedNodes.size();

    // -------------------- Prepare QSG Nodes:
    QSGNode* parentNode = oldNode;
    if (!oldNode) {
        parentNode = new QSGNode();
    } else {
        // update color in case it changed:
        // FIXME: is there a more efficient way to do this?
        for (int i=0; i<parentNode->childCount(); ++i) {
            QSGGeometryNode* childNode = static_cast<QSGGeometryNode*>(parentNode->childAtIndex(i));
            if (!childNode) continue;
            QSGFlatColorMaterial* material = static_cast<QSGFlatColorMaterial*>(childNode->material());
            if (!material) continue;
            material->setColor(m_color);
        }
    }
    // adapt child count:
    int childCount = parentNode->childCount();
    if (childCount < connectionCount) {
        for (int i=0; i<(connectionCount - childCount); ++i) {
            QSGGeometryNode* node = new QSGGeometryNode;
            QSGGeometry* geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 3);
            geometry->setDrawingMode(GL_TRIANGLE_STRIP);
            node->setGeometry(geometry);
            node->setFlag(QSGNode::OwnsGeometry);
            QSGFlatColorMaterial* material = new QSGFlatColorMaterial;
            material->setColor(m_color);
            node->setMaterial(material);
            node->setFlag(QSGNode::OwnsMaterial);
            parentNode->appendChildNode(node);
        }
    } else if (childCount > connectionCount) {
        for (int i=0; i<(childCount - connectionCount); ++i) {
            parentNode->removeChildNode(parentNode->childAtIndex(0));
        }
    }
    Q_ASSERT(parentNode->childCount() == connectionCount);

    // calculate common start point:
    const QPointF p0(width(), height() / 2);
    double widthOffset = m_lineWidth / 2;
    //const QPointF posInScene = mapToScene(QPointF(0, 0));


    for (int i=0; i<connectionCount; ++i) {
        NodeBase* otherNode = connectedNodes[i];
        if (!otherNode) continue;
        QQuickItem* otherGuiItem = otherNode->getGuiItem();
        if (!otherGuiItem) continue;
        const QPointF p3 = mapFromItem(otherGuiItem, QPointF(-otherGuiItem->width() / 2, otherGuiItem->height() / 2));
        int handleLength = std::max(50, std::min(int(p3.x() - p0.x()), 80));
        const QPointF p1(p0.x() + handleLength, p0.y());
        const QPointF p2(p3.x() - handleLength, p3.y());

        // calculate reasonable segment count:
        int segmentCount = qMax(16.0, qMin(qAbs(p3.y() - p0.y()) / 25, 50.0));
        int verticesCount = segmentCount * 2;

        QSGGeometryNode* qsgNode = static_cast<QSGGeometryNode*>(parentNode->childAtIndex(i));
        if (!qsgNode) continue;

        QSGGeometry* geometry = qsgNode->geometry();
        if (!geometry) continue;
        geometry->allocate(verticesCount);
        QSGGeometry::Point2D* vertices = geometry->vertexDataAsPoint2D();

        // triangulate cubic bezier curve:
        for (int i = 0; i < segmentCount; ++i) {
            // t is the position on the line:
            const qreal t = i / qreal(segmentCount - 1);

            // pos is the point on the curve at "t":
            const QPointF pos = calculateBezierPoint(t, p0, p1, p2, p3);

            // normal is the normal vector at that point
            const QPointF normal = normalFromTangent(calculateBezierTangent(t, p0, p1, p2, p3));

            // first is a point offsetted in the normal direction by lineWidth / 2 from pos
            const QPointF first = pos - normal * widthOffset;

            // ssecond is a point offsetted in the negative normal direction by lineWidth / 2 from pos
            const QPointF second = pos + normal * widthOffset;

            // add first and second as vertices to this geometry:
            vertices[i*2].set(first.x(), first.y());
            vertices[i*2+1].set(second.x(), second.y());
        }

        // tell Scene Graph that this items needs to be drawn:
        qsgNode->markDirty(QSGNode::DirtyGeometry);
    }

    return parentNode;
}