qt5base-lts/examples/graphicsview/elasticnodes/edge.cpp
Qt by Nokia 38be0d1383 Initial import from the monolithic Qt.
This is the beginning of revision history for this module. If you
want to look at revision history older than this, please refer to the
Qt Git wiki for how to use Git history grafting. At the time of
writing, this wiki is located here:

http://qt.gitorious.org/qt/pages/GitIntroductionWithQt

If you have already performed the grafting and you don't see any
history beyond this commit, try running "git log" with the "--follow"
argument.

Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12
2011-04-27 12:05:43 +02:00

150 lines
4.8 KiB
C++

/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
** the names of its contributors may be used to endorse or promote
** products derived from this software without specific prior written
** permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QPainter>
#include "edge.h"
#include "node.h"
#include <math.h>
static const double Pi = 3.14159265358979323846264338327950288419717;
static double TwoPi = 2.0 * Pi;
//! [0]
Edge::Edge(Node *sourceNode, Node *destNode)
: arrowSize(10)
{
setAcceptedMouseButtons(0);
source = sourceNode;
dest = destNode;
source->addEdge(this);
dest->addEdge(this);
adjust();
}
//! [0]
//! [1]
Node *Edge::sourceNode() const
{
return source;
}
Node *Edge::destNode() const
{
return dest;
}
//! [1]
//! [2]
void Edge::adjust()
{
if (!source || !dest)
return;
QLineF line(mapFromItem(source, 0, 0), mapFromItem(dest, 0, 0));
qreal length = line.length();
prepareGeometryChange();
if (length > qreal(20.)) {
QPointF edgeOffset((line.dx() * 10) / length, (line.dy() * 10) / length);
sourcePoint = line.p1() + edgeOffset;
destPoint = line.p2() - edgeOffset;
} else {
sourcePoint = destPoint = line.p1();
}
}
//! [2]
//! [3]
QRectF Edge::boundingRect() const
{
if (!source || !dest)
return QRectF();
qreal penWidth = 1;
qreal extra = (penWidth + arrowSize) / 2.0;
return QRectF(sourcePoint, QSizeF(destPoint.x() - sourcePoint.x(),
destPoint.y() - sourcePoint.y()))
.normalized()
.adjusted(-extra, -extra, extra, extra);
}
//! [3]
//! [4]
void Edge::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
if (!source || !dest)
return;
QLineF line(sourcePoint, destPoint);
if (qFuzzyCompare(line.length(), qreal(0.)))
return;
//! [4]
//! [5]
// Draw the line itself
painter->setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
painter->drawLine(line);
//! [5]
//! [6]
// Draw the arrows
double angle = ::acos(line.dx() / line.length());
if (line.dy() >= 0)
angle = TwoPi - angle;
QPointF sourceArrowP1 = sourcePoint + QPointF(sin(angle + Pi / 3) * arrowSize,
cos(angle + Pi / 3) * arrowSize);
QPointF sourceArrowP2 = sourcePoint + QPointF(sin(angle + Pi - Pi / 3) * arrowSize,
cos(angle + Pi - Pi / 3) * arrowSize);
QPointF destArrowP1 = destPoint + QPointF(sin(angle - Pi / 3) * arrowSize,
cos(angle - Pi / 3) * arrowSize);
QPointF destArrowP2 = destPoint + QPointF(sin(angle - Pi + Pi / 3) * arrowSize,
cos(angle - Pi + Pi / 3) * arrowSize);
painter->setBrush(Qt::black);
painter->drawPolygon(QPolygonF() << line.p1() << sourceArrowP1 << sourceArrowP2);
painter->drawPolygon(QPolygonF() << line.p2() << destArrowP1 << destArrowP2);
}
//! [6]