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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]
DiagramItem(DiagramType diagramType,QMenu * contextMenu,QGraphicsItem * parent)60 DiagramItem::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(200, 50);
69             path.arcTo(150, 0, 50, 50, 0, 90);
70             path.arcTo(50, 0, 50, 50, 90, 90);
71             path.arcTo(50, 50, 50, 50, 180, 90);
72             path.arcTo(150, 50, 50, 50, 270, 90);
73             path.lineTo(200, 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(QGraphicsItem::ItemIsMovable, true);
94     setFlag(QGraphicsItem::ItemIsSelectable, true);
95     setFlag(QGraphicsItem::ItemSendsGeometryChanges, true);
96 }
97 //! [0]
98 
99 //! [1]
removeArrow(Arrow * arrow)100 void DiagramItem::removeArrow(Arrow *arrow)
101 {
102     arrows.removeAll(arrow);
103 }
104 //! [1]
105 
106 //! [2]
removeArrows()107 void 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(arrow);
116         delete arrow;
117     }
118 }
119 //! [2]
120 
121 //! [3]
addArrow(Arrow * arrow)122 void DiagramItem::addArrow(Arrow *arrow)
123 {
124     arrows.append(arrow);
125 }
126 //! [3]
127 
128 //! [4]
image() const129 QPixmap DiagramItem::image() const
130 {
131     QPixmap pixmap(250, 250);
132     pixmap.fill(Qt::transparent);
133     QPainter painter(&pixmap);
134     painter.setPen(QPen(Qt::black, 8));
135     painter.translate(125, 125);
136     painter.drawPolyline(myPolygon);
137 
138     return pixmap;
139 }
140 //! [4]
141 
142 //! [5]
contextMenuEvent(QGraphicsSceneContextMenuEvent * event)143 void DiagramItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
144 {
145     scene()->clearSelection();
146     setSelected(true);
147     myContextMenu->exec(event->screenPos());
148 }
149 //! [5]
150 
151 //! [6]
itemChange(GraphicsItemChange change,const QVariant & value)152 QVariant DiagramItem::itemChange(GraphicsItemChange change, const QVariant &value)
153 {
154     if (change == QGraphicsItem::ItemPositionChange) {
155         for (Arrow *arrow : qAsConst(arrows))
156             arrow->updatePosition();
157     }
158 
159     return value;
160 }
161 //! [6]
162