Qt & qwtPlot --> keine plots bei Aufruf der Fkt. ausserhalb des plot Moduls

#ifndef PLOT_H

#define PLOT_H

#include <qapplication.h>

#include <qlayout.h>

#include <qwt_plot.h>

#include <qwt_plot_grid.h>

#include <qwt_plot_marker.h>

#include <qwt_plot_curve.h>

#include <qwt_legend.h>

#include <qwt_series_data.h>

#include <qwt_plot_canvas.h>

#include <qwt_plot_panner.h>

#include <qwt_plot_magnifier.h>

#include <qwt_text.h>

#include <qwt_math.h>

#include <math.h>

#define SIZE 15

class Plot : public QwtPlot

{

    Q_OBJECT

public:

    Plot(QWidget * = NULL);

    virtual ~Plot();

    void setPlotValue(double value);

    void populate();

protected:

    virtual void resizeEvent( QResizeEvent * );

private:

    void updateGradient();

    double cntX;

    QwtPlotCurve *density;

    double xData[SIZE];

    double yData[SIZE];

public slots:

    void addNewValue(double value);

signals:

};

#endif // PLOT_H

#include "plot.h"

Plot::Plot(QWidget *parent):

    QwtPlot( parent )

{

    xData[0] = 0;

    yData[0] = 0;

    // Insert new density curve

    density = new QwtPlotCurve("y = density");

    //density->setRenderHint(QwtPlotItem::RenderAntialiased);

    density->setStyle(QwtPlotCurve::Lines);

    density->setLegendAttribute(QwtPlotCurve::LegendShowLine, true);

    density->setPen(QPen(Qt::red));

    density->attach(this);

    // Draw grid

    QwtPlotGrid *grid = new QwtPlotGrid();

    grid->setPen(QPen(Qt::gray, 0.0, Qt::DotLine));

    grid->enableX(true);

    grid->enableXMin(true);

    grid->enableY(true);

    grid->enableYMin(false);

    grid->attach(this);

    // Insert markers

    //  ...a horizontal line at y = 0...

    QwtPlotMarker *mY = new QwtPlotMarker();

    mY->setLabel(QString::fromLatin1("y = 0"));

    mY->setLabelAlignment(Qt::AlignRight|Qt::AlignTop);

    mY->setLineStyle(QwtPlotMarker::HLine);

    mY->setYValue(0.0);

    mY->attach(this);

    //  ...a vertical line at x = 0...

    QwtPlotMarker *mX = new QwtPlotMarker();

    mX->setLabel(QString::fromLatin1("x = 0"));

    mX->setLabelAlignment(Qt::AlignLeft | Qt::AlignBottom);

    mX->setLabelOrientation(Qt::Vertical);

    mX->setLineStyle(QwtPlotMarker::VLine);

    mX->setLinePen(QPen(Qt::black, 0, Qt::DashDotLine));

    mX->setXValue(0.0);

    mX->attach(this);

    // panning with the left mouse button

    (void) new QwtPlotPanner( canvas() );

    // zoom in/out with the wheel

    (void) new QwtPlotMagnifier( canvas() );

    setAutoFillBackground( true );

    setPalette( QPalette( QColor( 165, 193, 228 ) ) );

    updateGradient();

    setTitle("A Simple QwtPlot Demonstration");

    insertLegend(new QwtLegend(), QwtPlot::RightLegend);

    // axes

    setAxisTitle(xBottom, "x -->" );

    setAxisScale(xBottom, 0.0, 10.0);

    setAxisTitle(yLeft, "y -->");

    setAxisScale(yLeft, -1.0, 1.0);

    // canvas

    canvas()->setLineWidth( 1 );

    canvas()->setFrameStyle( QFrame::Box | QFrame::Plain );

    canvas()->setBorderRadius( 15 );

    QPalette canvasPalette( Qt::white );

    canvasPalette.setColor( QPalette::Foreground, QColor( 133, 190, 232 ) );

    canvas()->setPalette( canvasPalette );

    //populate();         // beim Aufruf von hier aus, funktionieren die Plots...

}

Plot::~Plot()

{

}

void Plot::populate()

{

    qWarning()<<  "Plot : populate()";

    double maxD = 0;

    double minD = 1;

    double maxS = 0;

    double minS = 1;

    double dens = 2.0;

    unsigned int sample = 0;

    unsigned int x = 0;

    unsigned int y = 0;

    while(sample < 5)

    {

        xData[x++]= sample;

        yData[y++]= dens;

        maxS = sample;

        minS = sample++;

        maxD = dens;

        minD = dens++;

        setAxisScale(xBottom, (int)minS-1, (int)maxS+1);

        setAxisScale(yLeft,   (int)minD-1, (int)maxD+1);

        density->setSamples(xData, yData, sample);

    }

    setAutoReplot(true);

    // Call "replot()" to refresh plot displaying

    replot();

}