/****************************************************************************
**
** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (developer.feedback@nokia.com)
**
** This file is part of the HbCore module of the UI Extensions for Mobile.
**
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this file.
** Please review the following information to ensure the GNU Lesser General
** Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at developer.feedback@nokia.com.
**
****************************************************************************/
#include "hbvelocitycalculator_p.h"
#include "hbpointrecorder_p.h"
#include "hbgestures_p.h"
#include <QPointF>
#include <QDebug>
//#define VELOCITY_DEBUG
#ifndef VELOCITY_DEBUG
# define DEBUG if (0) qDebug
#else
# define DEBUG qDebug
#endif
/*!
@hbcore
\internals
\class HbVelocityCalculator
\brief Class to calculate velocity from point.
*/
/*!
\internal
\brief
\return
*/
HbVelocityCalculator::HbVelocityCalculator(
const HbPointRecorder& listX,
const HbPointRecorder& listY )
:
mListX( listX ),
mListY( listY )
{
}
/*!
\internal
\brief
\return
*/
QPointF HbVelocityCalculator::velocity( qint64 currentTime ) const
{
QPointF velocity(0.0, 0.0);
velocity.setX(calculate_velocity(mListX, currentTime));
velocity.setY(calculate_velocity(mListY, currentTime));
DEBUG() << "Velocity: " << velocity;
return velocity;
}
/*!
\internal
\brief
\return
*/
qreal HbVelocityCalculator::calculate_velocity(
const HbPointRecorder &list,
qint64 currentTime) const
{
if (list.count() < 2) {
return 0.0;
}
if (currentTime-list.lastTime() >= HbVelocityStopTime) {
return 0.0;
}
// Accumulate the distance from previous point until we have sufficient sample
qreal delta = 0.0;
qint64 timeDelta = 0;
int i = list.count();
while (timeDelta < HbVelocitySampleTime && i > 0) {
i--;
timeDelta = currentTime - list.at(i).second;
}
if(timeDelta <= 0) {
return 0.0;
}
delta = list.lastPoint() - list.at(i).first;
return delta / (qreal)(timeDelta);
}