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50
51#include "edge.h"
52#include "node.h"
53
54#include <QPainter>
55#include <QtMath>
56
57//! [0]
58Edge::Edge(Node *sourceNode, Node *destNode)
59 : source(sourceNode), dest(destNode)
60{
61 setAcceptedMouseButtons(Qt::NoButton);
62 source->addEdge(edge: this);
63 dest->addEdge(edge: this);
64 adjust();
65}
66//! [0]
67
68//! [1]
69Node *Edge::sourceNode() const
70{
71 return source;
72}
73
74Node *Edge::destNode() const
75{
76 return dest;
77}
78//! [1]
79
80//! [2]
81void Edge::adjust()
82{
83 if (!source || !dest)
84 return;
85
86 QLineF line(mapFromItem(item: source, ax: 0, ay: 0), mapFromItem(item: dest, ax: 0, ay: 0));
87 qreal length = line.length();
88
89 prepareGeometryChange();
90
91 if (length > qreal(20.)) {
92 QPointF edgeOffset((line.dx() * 10) / length, (line.dy() * 10) / length);
93 sourcePoint = line.p1() + edgeOffset;
94 destPoint = line.p2() - edgeOffset;
95 } else {
96 sourcePoint = destPoint = line.p1();
97 }
98}
99//! [2]
100
101//! [3]
102QRectF Edge::boundingRect() const
103{
104 if (!source || !dest)
105 return QRectF();
106
107 qreal penWidth = 1;
108 qreal extra = (penWidth + arrowSize) / 2.0;
109
110 return QRectF(sourcePoint, QSizeF(destPoint.x() - sourcePoint.x(),
111 destPoint.y() - sourcePoint.y()))
112 .normalized()
113 .adjusted(xp1: -extra, yp1: -extra, xp2: extra, yp2: extra);
114}
115//! [3]
116
117//! [4]
118void Edge::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
119{
120 if (!source || !dest)
121 return;
122
123 QLineF line(sourcePoint, destPoint);
124 if (qFuzzyCompare(p1: line.length(), p2: qreal(0.)))
125 return;
126//! [4]
127
128//! [5]
129 // Draw the line itself
130 painter->setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
131 painter->drawLine(l: line);
132//! [5]
133
134//! [6]
135 // Draw the arrows
136 double angle = std::atan2(y: -line.dy(), x: line.dx());
137
138 QPointF sourceArrowP1 = sourcePoint + QPointF(sin(x: angle + M_PI / 3) * arrowSize,
139 cos(x: angle + M_PI / 3) * arrowSize);
140 QPointF sourceArrowP2 = sourcePoint + QPointF(sin(x: angle + M_PI - M_PI / 3) * arrowSize,
141 cos(x: angle + M_PI - M_PI / 3) * arrowSize);
142 QPointF destArrowP1 = destPoint + QPointF(sin(x: angle - M_PI / 3) * arrowSize,
143 cos(x: angle - M_PI / 3) * arrowSize);
144 QPointF destArrowP2 = destPoint + QPointF(sin(x: angle - M_PI + M_PI / 3) * arrowSize,
145 cos(x: angle - M_PI + M_PI / 3) * arrowSize);
146
147 painter->setBrush(Qt::black);
148 painter->drawPolygon(polygon: QPolygonF() << line.p1() << sourceArrowP1 << sourceArrowP2);
149 painter->drawPolygon(polygon: QPolygonF() << line.p2() << destArrowP1 << destArrowP2);
150}
151//! [6]
152

source code of qtbase/examples/widgets/graphicsview/elasticnodes/edge.cpp