LibrePilot/ground/openpilotgcs/src/plugins/scope/plotdata.cpp

/**
 ******************************************************************************
 *
 * @file       plotdata.cpp
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
 * @addtogroup GCSPlugins GCS Plugins
 * @{
 * @addtogroup ScopePlugin Scope Gadget Plugin
 * @{
 * @brief The scope Gadget, graphically plots the states of UAVObjects
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */


#include "plotdata.h"
#include <math.h>
#include <QDebug>

PlotData::PlotData(UAVObject *object, UAVObjectField *field, int element,
                   int scaleOrderFactor, int meanSamples, QString mathFunction,
                   double plotDataSize, QPen pen, bool antialiased) :
    m_scalePower(scaleOrderFactor), m_meanSamples(meanSamples),
    m_mathFunction(mathFunction), m_plotDataSize(plotDataSize),
    m_object(object), m_field(field), m_element(element)
{
    if (!m_field->getNumElements() > 1) {
        m_elementName = m_field->getElementNames().at(m_element);
    }

    // Create the curve
    m_plotName.append(QString("%1.%2").arg(m_object->getName()).arg(m_field->getName()));
    if (!m_elementName.isEmpty()) {
        m_plotName.append(QString(".%1").arg(m_elementName));
    }

    if (m_scalePower == 0) {
        m_plotName.append(QString(" (%1)").arg(m_field->getUnits()));
    } else {
        m_plotName.append(QString(" (x10^%1 %2)").arg(m_scalePower).arg(m_field->getUnits()));
    }

    m_plotCurve = new QwtPlotCurve(m_plotName);

    if (antialiased) {
        m_plotCurve->setRenderHint(QwtPlotCurve::RenderAntialiased);
    }

    m_plotCurve->setPen(pen);
    m_plotCurve->setSamples(m_xDataEntries, m_yDataEntries);

    m_meanSum         = 0.0f;
    m_correctionSum   = 0.0f;
    m_correctionCount = 0;
}

PlotData::~PlotData()
{
    m_plotCurve->detach();
    delete m_plotCurve;
}

void PlotData::updatePlotData()
{
    m_plotCurve->setSamples(m_xDataEntries, m_yDataEntries);
}

void PlotData::attach(QwtPlot *plot)
{
    m_plotCurve->attach(plot);
}

void PlotData::calcMathFunction(double currentValue)
{
    // Put the new value at the back
    m_yDataHistory.append(currentValue);

    // calculate average value
    m_meanSum += currentValue;
    if (m_yDataHistory.size() > m_meanSamples) {
        m_meanSum -= m_yDataHistory.first();
        m_yDataHistory.pop_front();
    }
    // make sure to correct the sum every meanSamples steps to prevent it
    // from running away due to floating point rounding errors
    m_correctionSum += currentValue;
    if (++m_correctionCount >= m_meanSamples) {
        m_meanSum = m_correctionSum;
        m_correctionSum = 0.0f;
        m_correctionCount = 0;
    }

    double boxcarAvg = m_meanSum / m_yDataHistory.size();
    if (m_mathFunction == "Standard deviation") {
        // Calculate square of sample standard deviation, with Bessel's correction
        double stdSum = 0;
        for (int i = 0; i < m_yDataHistory.size(); i++) {
            stdSum += pow(m_yDataHistory.at(i) - boxcarAvg, 2) / (m_meanSamples - 1);
        }
        m_yDataEntries.append(sqrt(stdSum));
    } else {
        m_yDataEntries.append(boxcarAvg);
    }
}

bool SequentialPlotData::append(UAVObject *obj)
{
    if (m_object == obj && m_field) {
        double currentValue = m_field->getValue(m_element).toDouble() * pow(10, m_scalePower);

        // Perform scope math, if necessary
        if (m_mathFunction == "Boxcar average" || m_mathFunction == "Standard deviation") {
            calcMathFunction(currentValue);
        } else {
            m_yDataEntries.append(currentValue);
        }

        if (m_yDataEntries.size() > m_plotDataSize) {
            // If new data overflows the window, remove old data...
            m_yDataEntries.pop_front();
        } else {
            // ...otherwise, add a new y point at position xData
            m_xDataEntries.insert(m_xDataEntries.size(), m_xDataEntries.size());
        }
        return true;
    }
    return false;
}

bool ChronoPlotData::append(UAVObject *obj)
{
    if (m_object == obj && m_field) {
        // Get the field of interest
        QDateTime NOW = QDateTime::currentDateTime(); // THINK ABOUT REIMPLEMENTING THIS TO SHOW UAVO TIME, NOT SYSTEM TIME
        double currentValue = m_field->getValue(m_element).toDouble() * pow(10, m_scalePower);

        // Perform scope math, if necessary
        if (m_mathFunction == "Boxcar average" || m_mathFunction == "Standard deviation") {
            calcMathFunction(currentValue);
        } else {
            m_yDataEntries.append(currentValue);
        }

        double valueX = NOW.toTime_t() + NOW.time().msec() / 1000.0;
        m_xDataEntries.append(valueX);

        // Remove stale data
        removeStaleData();
        return true;
    }
    return false;
}

void ChronoPlotData::removeStaleData()
{
    while (!m_xDataEntries.isEmpty() &&
           (m_xDataEntries.last() - m_xDataEntries.first()) > m_plotDataSize) {
            m_yDataEntries.pop_front();
            m_xDataEntries.pop_front();
    }
}