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50
51
52#include "arrow.h"
53#include "diagramitem.h"
54
55#include <QPainter>
56#include <QPen>
57#include <QtMath>
58
59//! [0]
60Arrow::Arrow(DiagramItem *startItem, DiagramItem *endItem, QGraphicsItem *parent)
61 : QGraphicsLineItem(parent), myStartItem(startItem), myEndItem(endItem)
62{
63 setFlag(flag: QGraphicsItem::ItemIsSelectable, enabled: true);
64 setPen(QPen(myColor, 2, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
65}
66//! [0]
67
68//! [1]
69QRectF Arrow::boundingRect() const
70{
71 qreal extra = (pen().width() + 20) / 2.0;
72
73 return QRectF(line().p1(), QSizeF(line().p2().x() - line().p1().x(),
74 line().p2().y() - line().p1().y()))
75 .normalized()
76 .adjusted(xp1: -extra, yp1: -extra, xp2: extra, yp2: extra);
77}
78//! [1]
79
80//! [2]
81QPainterPath Arrow::shape() const
82{
83 QPainterPath path = QGraphicsLineItem::shape();
84 path.addPolygon(polygon: arrowHead);
85 return path;
86}
87//! [2]
88
89//! [3]
90void Arrow::updatePosition()
91{
92 QLineF line(mapFromItem(item: myStartItem, ax: 0, ay: 0), mapFromItem(item: myEndItem, ax: 0, ay: 0));
93 setLine(line);
94}
95//! [3]
96
97//! [4]
98void Arrow::paint(QPainter *painter, const QStyleOptionGraphicsItem *,
99 QWidget *)
100{
101 if (myStartItem->collidesWithItem(other: myEndItem))
102 return;
103
104 QPen myPen = pen();
105 myPen.setColor(myColor);
106 qreal arrowSize = 20;
107 painter->setPen(myPen);
108 painter->setBrush(myColor);
109//! [4] //! [5]
110
111 QLineF centerLine(myStartItem->pos(), myEndItem->pos());
112 QPolygonF endPolygon = myEndItem->polygon();
113 QPointF p1 = endPolygon.first() + myEndItem->pos();
114 QPointF intersectPoint;
115 for (int i = 1; i < endPolygon.count(); ++i) {
116 QPointF p2 = endPolygon.at(i) + myEndItem->pos();
117 QLineF polyLine = QLineF(p1, p2);
118 QLineF::IntersectionType intersectionType =
119 polyLine.intersects(l: centerLine, intersectionPoint: &intersectPoint);
120 if (intersectionType == QLineF::BoundedIntersection)
121 break;
122 p1 = p2;
123 }
124
125 setLine(QLineF(intersectPoint, myStartItem->pos()));
126//! [5] //! [6]
127
128 double angle = std::atan2(y: -line().dy(), x: line().dx());
129
130 QPointF arrowP1 = line().p1() + QPointF(sin(x: angle + M_PI / 3) * arrowSize,
131 cos(x: angle + M_PI / 3) * arrowSize);
132 QPointF arrowP2 = line().p1() + QPointF(sin(x: angle + M_PI - M_PI / 3) * arrowSize,
133 cos(x: angle + M_PI - M_PI / 3) * arrowSize);
134
135 arrowHead.clear();
136 arrowHead << line().p1() << arrowP1 << arrowP2;
137//! [6] //! [7]
138 painter->drawLine(l: line());
139 painter->drawPolygon(polygon: arrowHead);
140 if (isSelected()) {
141 painter->setPen(QPen(myColor, 1, Qt::DashLine));
142 QLineF myLine = line();
143 myLine.translate(adx: 0, ady: 4.0);
144 painter->drawLine(l: myLine);
145 myLine.translate(adx: 0,ady: -8.0);
146 painter->drawLine(l: myLine);
147 }
148}
149//! [7]
150

source code of qtbase/examples/widgets/graphicsview/diagramscene/arrow.cpp