/****************************************************************************
**
** Copyright (C) 1992-2005 Trolltech AS. All rights reserved.
**
** This file is part of the painting module of the Qt Toolkit.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
** information about Qt Commercial License Agreements.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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****************************************************************************/

#ifndef QBEZIER_P_H
#define QBEZIER_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists for the convenience
// of other Qt classes.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <qpoint.h>
#include <qline.h>

class QPolygonF;

class Q_GUI_EXPORT QBezier
{
public:
    QBezier();
    QBezier(qreal p1x, qreal p1y, qreal p2x, qreal p2y,
            qreal p3x, qreal p3y, qreal p4x, qreal p4y);
    QBezier(const QPointF &p1, const QPointF &p2, const QPointF &p3, const QPointF &p4);

    inline QPointF pointAt(qreal t) const;
    QPolygonF toPolygon() const;

    QPointF pt1() const { Q_ASSERT(valid); return QPointF(x1, y1); }
    QPointF pt2() const { Q_ASSERT(valid); return QPointF(x2, y2); }
    QPointF pt3() const { Q_ASSERT(valid); return QPointF(x3, y3); }
    QPointF pt4() const { Q_ASSERT(valid); return QPointF(x4, y4); }

    inline QPointF midPoint() const;
    inline QLineF midTangent() const;

    void split(QBezier *firstHalf, QBezier *secondHalf) const;
    int shifted(QBezier *curveSegments, int maxSegmets, float offset, float threshold) const;

private:
    void init();

    bool valid;
    qreal x1, y1, x2, y2, x3, y3, x4, y4;
    qreal ax, bx, cx, dx, ay, by, cy, dy;
};

inline QPointF QBezier::midPoint() const
{
    return QPointF(ax/8 + bx/4 + cx/2 + dx, ay/8 + by/4 + cy/2 + dy);
}

inline QLineF QBezier::midTangent() const
{
    QPointF mid = midPoint();
    QLineF dir(QLineF(x1, y1, x2, y2).pointAt(0.5), QLineF(x3, y3, x4, y4).pointAt(0.5));
    return QLineF(mid.x() - dir.dx(), mid.y() - dir.dy(),
                  mid.x() + dir.dx(), mid.y() + dir.dy());
}

inline QPointF QBezier::pointAt(qreal t) const
{
    Q_ASSERT(valid);
    Q_ASSERT(t >= 0);
    Q_ASSERT(t <= 1);
    return QPointF(ax*t*t*t + bx*t*t + cx*t + dx,
                   ay*t*t*t + by*t*t + cy*t + dy);
}

#endif // QBEZIER_P_H
