source: trunk/examples/graphicsview/elasticnodes/edge.cpp@ 846

Last change on this file since 846 was 846, checked in by Dmitry A. Kuminov, 14 years ago

trunk: Merged in qt 4.7.2 sources from branches/vendor/nokia/qt.

File size: 4.8 KB
Line 
1/****************************************************************************
2**
3** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
4** All rights reserved.
5** Contact: Nokia Corporation (qt-info@nokia.com)
6**
7** This file is part of the examples of the Qt Toolkit.
8**
9** $QT_BEGIN_LICENSE:BSD$
10** You may use this file under the terms of the BSD license as follows:
11**
12** "Redistribution and use in source and binary forms, with or without
13** modification, are permitted provided that the following conditions are
14** met:
15** * Redistributions of source code must retain the above copyright
16** notice, this list of conditions and the following disclaimer.
17** * Redistributions in binary form must reproduce the above copyright
18** notice, this list of conditions and the following disclaimer in
19** the documentation and/or other materials provided with the
20** distribution.
21** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
22** the names of its contributors may be used to endorse or promote
23** products derived from this software without specific prior written
24** permission.
25**
26** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
27** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
28** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
29** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
30** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
31** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
32** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
36** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
37** $QT_END_LICENSE$
38**
39****************************************************************************/
40
41#include <QPainter>
42
43#include "edge.h"
44#include "node.h"
45
46#include <math.h>
47
48static const double Pi = 3.14159265358979323846264338327950288419717;
49static double TwoPi = 2.0 * Pi;
50
51//! [0]
52Edge::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]
65Node *Edge::sourceNode() const
66{
67 return source;
68}
69
70Node *Edge::destNode() const
71{
72 return dest;
73}
74//! [1]
75
76//! [2]
77void 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]
98QRectF 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]
114void 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]
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