/****************************************************************************
**
** 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 <QtGui>

#include "arrow.h"
#include <math.h>

const qreal Pi = 3.14;

//! [0]
Arrow::Arrow(DiagramItem *startItem, DiagramItem *endItem,
         QGraphicsItem *parent, QGraphicsScene *scene)
    : QGraphicsLineItem(parent, scene)
{
    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]
