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/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Quick Templates 2 module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL3$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPLv3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or later as published by the Free
** Software Foundation and appearing in the file LICENSE.GPL included in
** the packaging of this file. Please review the following information to
** ensure the GNU General Public License version 2.0 requirements will be
** met: http://www.gnu.org/licenses/gpl-2.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qquickvelocitycalculator_p_p.h"
#include <QtCore/qdebug.h>
QT_BEGIN_NAMESPACE
/*
Usage:
QQuickVelocityCalculator velocityCalculator;
// ...
velocityCalcular.startMeasuring(event->pos(), event->timestamp());
velocityCalcular.stopMeasuring(event->pos(), event->timestamp());
// ...
if (velocityCalculator.velocity().x() > someAmount)
doSomething();
else if (velocityCalculator.velocity().x() < -someAmount)
doSomethingElse();
*/
void QQuickVelocityCalculator::startMeasuring(const QPointF &point1, qint64 timestamp)
{
m_point1 = point1;
if (timestamp != 0)
m_point1Timestamp = timestamp;
else
m_timer.start();
}
void QQuickVelocityCalculator::stopMeasuring(const QPointF &point2, qint64 timestamp)
{
if (timestamp == 0 && !m_timer.isValid()) {
qWarning() << "QQuickVelocityCalculator: a call to stopMeasuring() must be preceded by a call to startMeasuring()";
return;
}
m_point2 = point2;
m_point2Timestamp = timestamp != 0 ? timestamp : m_timer.elapsed();
m_timer.invalidate();
}
void QQuickVelocityCalculator::reset()
{
m_point1 = QPointF();
m_point2 = QPointF();
m_point1Timestamp = 0;
m_point2Timestamp = 0;
m_timer.invalidate();
}
QPointF QQuickVelocityCalculator::velocity() const
{
if ((m_point2Timestamp == 0 || m_point1Timestamp == m_point2Timestamp) && !m_timer.isValid())
return QPointF();
const qreal secondsElapsed = (m_point2Timestamp != 0 ? m_point2Timestamp - m_point1Timestamp : m_timer.elapsed()) / 1000.0;
const QPointF distance = m_point2 - m_point1;
return distance / secondsElapsed;
}
QT_END_NAMESPACE
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