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| |
| #include "edge.h" |
| #include "node.h" |
| #include "graphwidget.h" |
| |
| #include <QGraphicsScene> |
| #include <QGraphicsSceneMouseEvent> |
| #include <QPainter> |
| #include <QStyleOption> |
| |
| //! [0] |
| Node::Node(GraphWidget *graphWidget) |
| : graph(graphWidget) |
| { |
| setFlag(ItemIsMovable); |
| setFlag(ItemSendsGeometryChanges); |
| setCacheMode(DeviceCoordinateCache); |
| setZValue(-1); |
| } |
| //! [0] |
| |
| //! [1] |
| void Node::addEdge(Edge *edge) |
| { |
| edgeList << edge; |
| edge->adjust(); |
| } |
| |
| QVector<Edge *> Node::edges() const |
| { |
| return edgeList; |
| } |
| //! [1] |
| |
| //! [2] |
| void Node::calculateForces() |
| { |
| if (!scene() || scene()->mouseGrabberItem() == this) { |
| newPos = pos(); |
| return; |
| } |
| //! [2] |
| |
| //! [3] |
| // Sum up all forces pushing this item away |
| qreal xvel = 0; |
| qreal yvel = 0; |
| const QList<QGraphicsItem *> items = scene()->items(); |
| for (QGraphicsItem *item : items) { |
| Node *node = qgraphicsitem_cast<Node *>(item); |
| if (!node) |
| continue; |
| |
| QPointF vec = mapToItem(node, 0, 0); |
| qreal dx = vec.x(); |
| qreal dy = vec.y(); |
| double l = 2.0 * (dx * dx + dy * dy); |
| if (l > 0) { |
| xvel += (dx * 150.0) / l; |
| yvel += (dy * 150.0) / l; |
| } |
| } |
| //! [3] |
| |
| //! [4] |
| // Now subtract all forces pulling items together |
| double weight = (edgeList.size() + 1) * 10; |
| for (const Edge *edge : qAsConst(edgeList)) { |
| QPointF vec; |
| if (edge->sourceNode() == this) |
| vec = mapToItem(edge->destNode(), 0, 0); |
| else |
| vec = mapToItem(edge->sourceNode(), 0, 0); |
| xvel -= vec.x() / weight; |
| yvel -= vec.y() / weight; |
| } |
| //! [4] |
| |
| //! [5] |
| if (qAbs(xvel) < 0.1 && qAbs(yvel) < 0.1) |
| xvel = yvel = 0; |
| //! [5] |
| |
| //! [6] |
| QRectF sceneRect = scene()->sceneRect(); |
| newPos = pos() + QPointF(xvel, yvel); |
| newPos.setX(qMin(qMax(newPos.x(), sceneRect.left() + 10), sceneRect.right() - 10)); |
| newPos.setY(qMin(qMax(newPos.y(), sceneRect.top() + 10), sceneRect.bottom() - 10)); |
| } |
| //! [6] |
| |
| //! [7] |
| bool Node::advancePosition() |
| { |
| if (newPos == pos()) |
| return false; |
| |
| setPos(newPos); |
| return true; |
| } |
| //! [7] |
| |
| //! [8] |
| QRectF Node::boundingRect() const |
| { |
| qreal adjust = 2; |
| return QRectF( -10 - adjust, -10 - adjust, 23 + adjust, 23 + adjust); |
| } |
| //! [8] |
| |
| //! [9] |
| QPainterPath Node::shape() const |
| { |
| QPainterPath path; |
| path.addEllipse(-10, -10, 20, 20); |
| return path; |
| } |
| //! [9] |
| |
| //! [10] |
| void Node::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *) |
| { |
| painter->setPen(Qt::NoPen); |
| painter->setBrush(Qt::darkGray); |
| painter->drawEllipse(-7, -7, 20, 20); |
| |
| QRadialGradient gradient(-3, -3, 10); |
| if (option->state & QStyle::State_Sunken) { |
| gradient.setCenter(3, 3); |
| gradient.setFocalPoint(3, 3); |
| gradient.setColorAt(1, QColor(Qt::yellow).lighter(120)); |
| gradient.setColorAt(0, QColor(Qt::darkYellow).lighter(120)); |
| } else { |
| gradient.setColorAt(0, Qt::yellow); |
| gradient.setColorAt(1, Qt::darkYellow); |
| } |
| painter->setBrush(gradient); |
| |
| painter->setPen(QPen(Qt::black, 0)); |
| painter->drawEllipse(-10, -10, 20, 20); |
| } |
| //! [10] |
| |
| //! [11] |
| QVariant Node::itemChange(GraphicsItemChange change, const QVariant &value) |
| { |
| switch (change) { |
| case ItemPositionHasChanged: |
| for (Edge *edge : qAsConst(edgeList)) |
| edge->adjust(); |
| graph->itemMoved(); |
| break; |
| default: |
| break; |
| }; |
| |
| return QGraphicsItem::itemChange(change, value); |
| } |
| //! [11] |
| |
| //! [12] |
| void Node::mousePressEvent(QGraphicsSceneMouseEvent *event) |
| { |
| update(); |
| QGraphicsItem::mousePressEvent(event); |
| } |
| |
| void Node::mouseReleaseEvent(QGraphicsSceneMouseEvent *event) |
| { |
| update(); |
| QGraphicsItem::mouseReleaseEvent(event); |
| } |
| //! [12] |