1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "edge.h"
#include "node.h"
#include "graphwidget.h"
#include <QGraphicsScene>
#include <QGraphicsSceneMouseEvent>
#include <QPainter>
#include <QStyleOption>
//! [0]
Node::Node(GraphWidget *graphWidget)
: graph(graphWidget)
{
setFlag(ItemIsMovable);
setFlag(ItemSendsGeometryChanges);
setCacheMode(DeviceCoordinateCache);
setZValue(-1);
}
//! [0]
//! [1]
void Node::addEdge(Edge *edge)
{
edgeList << edge;
edge->adjust();
}
QList<Edge *> Node::edges() const
{
return edgeList;
}
//! [1]
//! [2]
void Node::calculateForces()
{
if (!scene() || scene()->mouseGrabberItem() == this) {
newPos = pos();
return;
}
//! [2]
//! [3]
// Sum up all forces pushing this item away
qreal xvel = 0;
qreal yvel = 0;
const QList<QGraphicsItem *> items = scene()->items();
for (QGraphicsItem *item : items) {
Node *node = qgraphicsitem_cast<Node *>(item);
if (!node)
continue;
QPointF vec = mapToItem(node, 0, 0);
qreal dx = vec.x();
qreal dy = vec.y();
double l = 2.0 * (dx * dx + dy * dy);
if (l > 0) {
xvel += (dx * 150.0) / l;
yvel += (dy * 150.0) / l;
}
}
//! [3]
//! [4]
// Now subtract all forces pulling items together
double weight = (edgeList.size() + 1) * 10;
for (const Edge *edge : std::as_const(edgeList)) {
QPointF vec;
if (edge->sourceNode() == this)
vec = mapToItem(edge->destNode(), 0, 0);
else
vec = mapToItem(edge->sourceNode(), 0, 0);
xvel -= vec.x() / weight;
yvel -= vec.y() / weight;
}
//! [4]
//! [5]
if (qAbs(xvel) < 0.1 && qAbs(yvel) < 0.1)
xvel = yvel = 0;
//! [5]
//! [6]
QRectF sceneRect = scene()->sceneRect();
newPos = pos() + QPointF(xvel, yvel);
newPos.setX(qMin(qMax(newPos.x(), sceneRect.left() + 10), sceneRect.right() - 10));
newPos.setY(qMin(qMax(newPos.y(), sceneRect.top() + 10), sceneRect.bottom() - 10));
}
//! [6]
//! [7]
bool Node::advancePosition()
{
if (newPos == pos())
return false;
setPos(newPos);
return true;
}
//! [7]
//! [8]
QRectF Node::boundingRect() const
{
qreal adjust = 2;
return QRectF( -10 - adjust, -10 - adjust, 23 + adjust, 23 + adjust);
}
//! [8]
//! [9]
QPainterPath Node::shape() const
{
QPainterPath path;
path.addEllipse(-10, -10, 20, 20);
return path;
}
//! [9]
//! [10]
void Node::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *)
{
painter->setPen(Qt::NoPen);
painter->setBrush(Qt::darkGray);
painter->drawEllipse(-7, -7, 20, 20);
QRadialGradient gradient(-3, -3, 10);
if (option->state & QStyle::State_Sunken) {
gradient.setCenter(3, 3);
gradient.setFocalPoint(3, 3);
gradient.setColorAt(1, QColor(Qt::yellow).lighter(120));
gradient.setColorAt(0, QColor(Qt::darkYellow).lighter(120));
} else {
gradient.setColorAt(0, Qt::yellow);
gradient.setColorAt(1, Qt::darkYellow);
}
painter->setBrush(gradient);
painter->setPen(QPen(Qt::black, 0));
painter->drawEllipse(-10, -10, 20, 20);
}
//! [10]
//! [11]
QVariant Node::itemChange(GraphicsItemChange change, const QVariant &value)
{
switch (change) {
case ItemPositionHasChanged:
for (Edge *edge : std::as_const(edgeList))
edge->adjust();
graph->itemMoved();
break;
default:
break;
};
return QGraphicsItem::itemChange(change, value);
}
//! [11]
//! [12]
void Node::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
update();
QGraphicsItem::mousePressEvent(event);
}
void Node::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
update();
QGraphicsItem::mouseReleaseEvent(event);
}
//! [12]
|
