Revision control
++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include "edge.h"
++ #include "node.h"
++
++ #include <QPainter>
++ #include <QtMath>
++
++ //! [0]
++ Edge::Edge(Node *sourceNode, Node *destNode)
++ : source(sourceNode), dest(destNode)
++ {
++ setAcceptedMouseButtons(Qt::NoButton);
++ source->addEdge(this);
++ dest->addEdge(this);
++ adjust();
++ }
++ //! [0]
++
++ //! [1]
++ Node *Edge::sourceNode() const
++ {
++ return source;
++ }
++
++ Node *Edge::destNode() const
++ {
++ return dest;
++ }
++ //! [1]
++
++ //! [2]
++ void Edge::adjust()
++ {
++ if (!source || !dest)
++ return;
++
++ QLineF line(mapFromItem(source, 0, 0), mapFromItem(dest, 0, 0));
++ qreal length = line.length();
++
++ prepareGeometryChange();
++
++ if (length > qreal(20.)) {
++ QPointF edgeOffset((line.dx() * 10) / length, (line.dy() * 10) / length);
++ sourcePoint = line.p1() + edgeOffset;
++ destPoint = line.p2() - edgeOffset;
++ } else {
++ sourcePoint = destPoint = line.p1();
++ }
++ }
++ //! [2]
++
++ //! [3]
++ QRectF Edge::boundingRect() const
++ {
++ if (!source || !dest)
++ return QRectF();
++
++ qreal penWidth = 1;
++ qreal extra = (penWidth + arrowSize) / 2.0;
++
++ return QRectF(sourcePoint, QSizeF(destPoint.x() - sourcePoint.x(),
++ destPoint.y() - sourcePoint.y()))
++ .normalized()
++ .adjusted(-extra, -extra, extra, extra);
++ }
++ //! [3]
++
++ //! [4]
++ void Edge::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
++ {
++ if (!source || !dest)
++ return;
++
++ QLineF line(sourcePoint, destPoint);
++ if (qFuzzyCompare(line.length(), qreal(0.)))
++ return;
++ //! [4]
++
++ //! [5]
++ // Draw the line itself
++ painter->setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
++ painter->drawLine(line);
++ //! [5]
++
++ //! [6]
++ // Draw the arrows
++ double angle = std::atan2(-line.dy(), line.dx());
++
++ QPointF sourceArrowP1 = sourcePoint + QPointF(sin(angle + M_PI / 3) * arrowSize,
++ cos(angle + M_PI / 3) * arrowSize);
++ QPointF sourceArrowP2 = sourcePoint + QPointF(sin(angle + M_PI - M_PI / 3) * arrowSize,
++ cos(angle + M_PI - M_PI / 3) * arrowSize);
++ QPointF destArrowP1 = destPoint + QPointF(sin(angle - M_PI / 3) * arrowSize,
++ cos(angle - M_PI / 3) * arrowSize);
++ QPointF destArrowP2 = destPoint + QPointF(sin(angle - M_PI + M_PI / 3) * arrowSize,
++ cos(angle - M_PI + M_PI / 3) * arrowSize);
++
++ painter->setBrush(Qt::black);
++ painter->drawPolygon(QPolygonF() << line.p1() << sourceArrowP1 << sourceArrowP2);
++ painter->drawPolygon(QPolygonF() << line.p2() << destArrowP1 << destArrowP2);
++ }
++ //! [6]