#include <stdlib.h>#include <qwt_painter.h>#include <qwt_plot_canvas.h>#include <qwt_plot_marker.h>#include <qwt_plot_curve.h>#include <qwt_scale_widget.h>#include <qwt_legend.h>#include <qwt_scale_draw.h>#include <qwt_math.h>#include "data_plot.h"////  Initialize main window//DataPlot::DataPlot(QWidget *parent):    QwtPlot(parent),    d_interval(0),    d_timerId(-1){    // Disable polygon clipping    QwtPainter::setDeviceClipping(false);    // We don't need the cache here    canvas()->setPaintAttribute(QwtPlotCanvas::PaintCached, false);    canvas()->setPaintAttribute(QwtPlotCanvas::PaintPacked, false);#if QT_VERSION >= 0x040000#ifdef Q_WS_X11    /*       Qt::WA_PaintOnScreen is only supported for X11, but leads       to substantial bugs with Qt 4.2.x/Windows     */    canvas()->setAttribute(Qt::WA_PaintOnScreen, true);#endif#endif    alignScales();        //  Initialize data    for (int i = 0; i< PLOT_SIZE; i++)    {        d_x[i] = 0.5 * i;     // time axis        d_y[i] = 0;        d_z[i] = 0;    }    // Assign a title    setTitle("A Test for High Refresh Rates");    insertLegend(new QwtLegend(), QwtPlot::BottomLegend);    // Insert new curves    QwtPlotCurve *cRight = new QwtPlotCurve("Data Moving Right");    cRight->attach(this);    QwtPlotCurve *cLeft = new QwtPlotCurve("Data Moving Left");    cLeft->attach(this);    // Set curve styles    cRight->setPen(QPen(Qt::red));    cLeft->setPen(QPen(Qt::blue));    // Attach (don't copy) data. Both curves use the same x array.    cRight->setRawData(d_x, d_y, PLOT_SIZE);    cLeft->setRawData(d_x, d_z, PLOT_SIZE);#if 0    //  Insert zero line at y = 0    QwtPlotMarker *mY = new QwtPlotMarker();    mY->setLabelAlignment(Qt::AlignRight|Qt::AlignTop);    mY->setLineStyle(QwtPlotMarker::HLine);    mY->setYValue(0.0);    mY->attach(this);#endif    // Axis     setAxisTitle(QwtPlot::xBottom, "Time/seconds");    setAxisScale(QwtPlot::xBottom, 0, 100);    setAxisTitle(QwtPlot::yLeft, "Values");    setAxisScale(QwtPlot::yLeft, -1.5, 1.5);        setTimerInterval(0.0); }////  Set a plain canvas frame and align the scales to it//void DataPlot::alignScales(){    // The code below shows how to align the scales to    // the canvas frame, but is also a good example demonstrating    // why the spreaded API needs polishing.    canvas()->setFrameStyle(QFrame::Box | QFrame::Plain );    canvas()->setLineWidth(1);    for ( int i = 0; i < QwtPlot::axisCnt; i++ )    {        QwtScaleWidget *scaleWidget = (QwtScaleWidget *)axisWidget(i);        if ( scaleWidget )            scaleWidget->setMargin(0);        QwtScaleDraw *scaleDraw = (QwtScaleDraw *)axisScaleDraw(i);        if ( scaleDraw )            scaleDraw->enableComponent(QwtAbstractScaleDraw::Backbone, false);    }}void DataPlot::setTimerInterval(double ms){    d_interval = qRound(ms);    if ( d_timerId >= 0 )    {        killTimer(d_timerId);        d_timerId = -1;    }    if (d_interval >= 0 )        d_timerId = startTimer(d_interval);}//  Generate new values void DataPlot::timerEvent(QTimerEvent *){    static double phase = 0.0;    if (phase > (M_PI - 0.0001))         phase = 0.0;    // y moves from left to right:    // Shift y array right and assign new value to y[0].    for ( int i = PLOT_SIZE - 1; i > 0; i-- )        d_y[i] = d_y[i-1];    d_y[0] = sin(phase) * (-1.0 + 2.0 * double(rand()) / double(RAND_MAX));    for ( int j = 0; j < PLOT_SIZE - 1; j++ )        d_z[j] = d_z[j+1];    d_z[PLOT_SIZE - 1] = 0.8 - (2.0 * phase/M_PI) + 0.4 *         double(rand()) / double(RAND_MAX);    // update the display    replot();    phase += M_PI * 0.02;}