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50
51#include "diagramitem.h"
52#include "arrow.h"
53
54#include <QGraphicsScene>
55#include <QGraphicsSceneContextMenuEvent>
56#include <QMenu>
57#include <QPainter>
58
59//! [0]
60DiagramItem::DiagramItem(DiagramType diagramType, QMenu *contextMenu,
61 QGraphicsItem *parent)
62 : QGraphicsPolygonItem(parent), myDiagramType(diagramType)
63 , myContextMenu(contextMenu)
64{
65 QPainterPath path;
66 switch (myDiagramType) {
67 case StartEnd:
68 path.moveTo(x: 200, y: 50);
69 path.arcTo(x: 150, y: 0, w: 50, h: 50, startAngle: 0, arcLength: 90);
70 path.arcTo(x: 50, y: 0, w: 50, h: 50, startAngle: 90, arcLength: 90);
71 path.arcTo(x: 50, y: 50, w: 50, h: 50, startAngle: 180, arcLength: 90);
72 path.arcTo(x: 150, y: 50, w: 50, h: 50, startAngle: 270, arcLength: 90);
73 path.lineTo(x: 200, y: 25);
74 myPolygon = path.toFillPolygon();
75 break;
76 case Conditional:
77 myPolygon << QPointF(-100, 0) << QPointF(0, 100)
78 << QPointF(100, 0) << QPointF(0, -100)
79 << QPointF(-100, 0);
80 break;
81 case Step:
82 myPolygon << QPointF(-100, -100) << QPointF(100, -100)
83 << QPointF(100, 100) << QPointF(-100, 100)
84 << QPointF(-100, -100);
85 break;
86 default:
87 myPolygon << QPointF(-120, -80) << QPointF(-70, 80)
88 << QPointF(120, 80) << QPointF(70, -80)
89 << QPointF(-120, -80);
90 break;
91 }
92 setPolygon(myPolygon);
93 setFlag(flag: QGraphicsItem::ItemIsMovable, enabled: true);
94 setFlag(flag: QGraphicsItem::ItemIsSelectable, enabled: true);
95 setFlag(flag: QGraphicsItem::ItemSendsGeometryChanges, enabled: true);
96}
97//! [0]
98
99//! [1]
100void DiagramItem::removeArrow(Arrow *arrow)
101{
102 arrows.removeAll(t: arrow);
103}
104//! [1]
105
106//! [2]
107void DiagramItem::removeArrows()
108{
109 // need a copy here since removeArrow() will
110 // modify the arrows container
111 const auto arrowsCopy = arrows;
112 for (Arrow *arrow : arrowsCopy) {
113 arrow->startItem()->removeArrow(arrow);
114 arrow->endItem()->removeArrow(arrow);
115 scene()->removeItem(item: arrow);
116 delete arrow;
117 }
118}
119//! [2]
120
121//! [3]
122void DiagramItem::addArrow(Arrow *arrow)
123{
124 arrows.append(t: arrow);
125}
126//! [3]
127
128//! [4]
129QPixmap DiagramItem::image() const
130{
131 QPixmap pixmap(250, 250);
132 pixmap.fill(fillColor: Qt::transparent);
133 QPainter painter(&pixmap);
134 painter.setPen(QPen(Qt::black, 8));
135 painter.translate(dx: 125, dy: 125);
136 painter.drawPolyline(polyline: myPolygon);
137
138 return pixmap;
139}
140//! [4]
141
142//! [5]
143void DiagramItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
144{
145 scene()->clearSelection();
146 setSelected(true);
147 myContextMenu->exec(pos: event->screenPos());
148}
149//! [5]
150
151//! [6]
152QVariant DiagramItem::itemChange(GraphicsItemChange change, const QVariant &value)
153{
154 if (change == QGraphicsItem::ItemPositionChange) {
155 for (Arrow *arrow : qAsConst(t&: arrows))
156 arrow->updatePosition();
157 }
158
159 return value;
160}
161//! [6]
162

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