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40
41 #include <QPainter>
42
43 #include "edge.h"
44 #include "node.h"
45
46 #include <math.h>
47
48 static const double Pi = 3.14159265358979323846264338327950288419717;
49 static double TwoPi = 2.0 * Pi;
50
51 //! [0]
Edge(Node * sourceNode,Node * destNode)52 Edge::Edge(Node *sourceNode, Node *destNode)
53 : arrowSize(10)
54 {
55 setAcceptedMouseButtons(0);
56 source = sourceNode;
57 dest = destNode;
58 source->addEdge(this);
59 dest->addEdge(this);
60 adjust();
61 }
62 //! [0]
63
64 //! [1]
sourceNode() const65 Node *Edge::sourceNode() const
66 {
67 return source;
68 }
69
destNode() const70 Node *Edge::destNode() const
71 {
72 return dest;
73 }
74 //! [1]
75
76 //! [2]
adjust()77 void Edge::adjust()
78 {
79 if (!source || !dest)
80 return;
81
82 QLineF line(mapFromItem(source, 0, 0), mapFromItem(dest, 0, 0));
83 qreal length = line.length();
84
85 prepareGeometryChange();
86
87 if (length > qreal(20.)) {
88 QPointF edgeOffset((line.dx() * 10) / length, (line.dy() * 10) / length);
89 sourcePoint = line.p1() + edgeOffset;
90 destPoint = line.p2() - edgeOffset;
91 } else {
92 sourcePoint = destPoint = line.p1();
93 }
94 }
95 //! [2]
96
97 //! [3]
boundingRect() const98 QRectF Edge::boundingRect() const
99 {
100 if (!source || !dest)
101 return QRectF();
102
103 qreal penWidth = 1;
104 qreal extra = (penWidth + arrowSize) / 2.0;
105
106 return QRectF(sourcePoint, QSizeF(destPoint.x() - sourcePoint.x(),
107 destPoint.y() - sourcePoint.y()))
108 .normalized()
109 .adjusted(-extra, -extra, extra, extra);
110 }
111 //! [3]
112
113 //! [4]
paint(QPainter * painter,const QStyleOptionGraphicsItem *,QWidget *)114 void Edge::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
115 {
116 if (!source || !dest)
117 return;
118
119 QLineF line(sourcePoint, destPoint);
120 if (qFuzzyCompare(line.length(), qreal(0.)))
121 return;
122 //! [4]
123
124 //! [5]
125 // Draw the line itself
126 painter->setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
127 painter->drawLine(line);
128 //! [5]
129
130 //! [6]
131 // Draw the arrows
132 double angle = ::acos(line.dx() / line.length());
133 if (line.dy() >= 0)
134 angle = TwoPi - angle;
135
136 QPointF sourceArrowP1 = sourcePoint + QPointF(sin(angle + Pi / 3) * arrowSize,
137 cos(angle + Pi / 3) * arrowSize);
138 QPointF sourceArrowP2 = sourcePoint + QPointF(sin(angle + Pi - Pi / 3) * arrowSize,
139 cos(angle + Pi - Pi / 3) * arrowSize);
140 QPointF destArrowP1 = destPoint + QPointF(sin(angle - Pi / 3) * arrowSize,
141 cos(angle - Pi / 3) * arrowSize);
142 QPointF destArrowP2 = destPoint + QPointF(sin(angle - Pi + Pi / 3) * arrowSize,
143 cos(angle - Pi + Pi / 3) * arrowSize);
144
145 painter->setBrush(Qt::black);
146 painter->drawPolygon(QPolygonF() << line.p1() << sourceArrowP1 << sourceArrowP2);
147 painter->drawPolygon(QPolygonF() << line.p2() << destArrowP1 << destArrowP2);
148 }
149 //! [6]
150