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50
51 #include "edge.h"
52 #include "node.h"
53
54 #include <QPainter>
55 #include <QtMath>
56
57 //! [0]
Edge(Node * sourceNode,Node * destNode)58 Edge::Edge(Node *sourceNode, Node *destNode)
59 : source(sourceNode), dest(destNode)
60 {
61 setAcceptedMouseButtons(Qt::NoButton);
62 source->addEdge(this);
63 dest->addEdge(this);
64 adjust();
65 }
66 //! [0]
67
68 //! [1]
sourceNode() const69 Node *Edge::sourceNode() const
70 {
71 return source;
72 }
73
destNode() const74 Node *Edge::destNode() const
75 {
76 return dest;
77 }
78 //! [1]
79
80 //! [2]
adjust()81 void Edge::adjust()
82 {
83 if (!source || !dest)
84 return;
85
86 QLineF line(mapFromItem(source, 0, 0), mapFromItem(dest, 0, 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]
boundingRect() const102 QRectF 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(-extra, -extra, extra, extra);
114 }
115 //! [3]
116
117 //! [4]
paint(QPainter * painter,const QStyleOptionGraphicsItem *,QWidget *)118 void Edge::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
119 {
120 if (!source || !dest)
121 return;
122
123 QLineF line(sourcePoint, destPoint);
124 if (qFuzzyCompare(line.length(), 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(line);
132 //! [5]
133
134 //! [6]
135 // Draw the arrows
136 double angle = std::atan2(-line.dy(), line.dx());
137
138 QPointF sourceArrowP1 = sourcePoint + QPointF(sin(angle + M_PI / 3) * arrowSize,
139 cos(angle + M_PI / 3) * arrowSize);
140 QPointF sourceArrowP2 = sourcePoint + QPointF(sin(angle + M_PI - M_PI / 3) * arrowSize,
141 cos(angle + M_PI - M_PI / 3) * arrowSize);
142 QPointF destArrowP1 = destPoint + QPointF(sin(angle - M_PI / 3) * arrowSize,
143 cos(angle - M_PI / 3) * arrowSize);
144 QPointF destArrowP2 = destPoint + QPointF(sin(angle - M_PI + M_PI / 3) * arrowSize,
145 cos(angle - M_PI + M_PI / 3) * arrowSize);
146
147 painter->setBrush(Qt::black);
148 painter->drawPolygon(QPolygonF() << line.p1() << sourceArrowP1 << sourceArrowP2);
149 painter->drawPolygon(QPolygonF() << line.p2() << destArrowP1 << destArrowP2);
150 }
151 //! [6]
152