qt5base-lts/examples/widgets/graphicsview/diagramscene/arrow.cpp

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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** 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:
**
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** 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.
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** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of The Qt Company Ltd 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.
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**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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****************************************************************************/
#include "arrow.h"
#include <math.h>
#include <QPen>
#include <QPainter>
const qreal Pi = 3.14;
//! [0]
Arrow::Arrow(DiagramItem *startItem, DiagramItem *endItem, QGraphicsItem *parent)
: QGraphicsLineItem(parent)
{
myStartItem = startItem;
myEndItem = endItem;
setFlag(QGraphicsItem::ItemIsSelectable, true);
myColor = Qt::black;
setPen(QPen(myColor, 2, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
}
//! [0]
//! [1]
QRectF Arrow::boundingRect() const
{
qreal extra = (pen().width() + 20) / 2.0;
return QRectF(line().p1(), QSizeF(line().p2().x() - line().p1().x(),
line().p2().y() - line().p1().y()))
.normalized()
.adjusted(-extra, -extra, extra, extra);
}
//! [1]
//! [2]
QPainterPath Arrow::shape() const
{
QPainterPath path = QGraphicsLineItem::shape();
path.addPolygon(arrowHead);
return path;
}
//! [2]
//! [3]
void Arrow::updatePosition()
{
QLineF line(mapFromItem(myStartItem, 0, 0), mapFromItem(myEndItem, 0, 0));
setLine(line);
}
//! [3]
//! [4]
void Arrow::paint(QPainter *painter, const QStyleOptionGraphicsItem *,
QWidget *)
{
if (myStartItem->collidesWithItem(myEndItem))
return;
QPen myPen = pen();
myPen.setColor(myColor);
qreal arrowSize = 20;
painter->setPen(myPen);
painter->setBrush(myColor);
//! [4] //! [5]
QLineF centerLine(myStartItem->pos(), myEndItem->pos());
QPolygonF endPolygon = myEndItem->polygon();
QPointF p1 = endPolygon.first() + myEndItem->pos();
QPointF p2;
QPointF intersectPoint;
QLineF polyLine;
for (int i = 1; i < endPolygon.count(); ++i) {
p2 = endPolygon.at(i) + myEndItem->pos();
polyLine = QLineF(p1, p2);
QLineF::IntersectType intersectType =
polyLine.intersect(centerLine, &intersectPoint);
if (intersectType == QLineF::BoundedIntersection)
break;
p1 = p2;
}
setLine(QLineF(intersectPoint, myStartItem->pos()));
//! [5] //! [6]
double angle = ::acos(line().dx() / line().length());
if (line().dy() >= 0)
angle = (Pi * 2) - angle;
QPointF arrowP1 = line().p1() + QPointF(sin(angle + Pi / 3) * arrowSize,
cos(angle + Pi / 3) * arrowSize);
QPointF arrowP2 = line().p1() + QPointF(sin(angle + Pi - Pi / 3) * arrowSize,
cos(angle + Pi - Pi / 3) * arrowSize);
arrowHead.clear();
arrowHead << line().p1() << arrowP1 << arrowP2;
//! [6] //! [7]
painter->drawLine(line());
painter->drawPolygon(arrowHead);
if (isSelected()) {
painter->setPen(QPen(myColor, 1, Qt::DashLine));
QLineF myLine = line();
myLine.translate(0, 4.0);
painter->drawLine(myLine);
myLine.translate(0,-8.0);
painter->drawLine(myLine);
}
}
//! [7]