plot.cpp

QWT5.01用于Qt开发的二维图形库程序

#include <qwt_color_map.h>
#include <qwt_plot_spectrogram.h>
#include <qwt_scale_widget.h>
#include <qwt_scale_draw.h>
#include <qwt_plot_zoomer.h>
#include <qwt_plot_panner.h>
#include <qwt_plot_layout.h>
#include "plot.h"

class SpectrogramData: public QwtRasterData
{
public:
    SpectrogramData():
        QwtRasterData(QwtDoubleRect(-1.5, -1.5, 3.0, 3.0))
    {
    }

    virtual QwtRasterData *copy() const
    {
        return new SpectrogramData();
    }

    virtual QwtDoubleInterval range() const
    {
        return QwtDoubleInterval(0.0, 10.0);
    }

    virtual double value(double x, double y) const
    {
        const double c = 0.842;

        const double v1 = x * x + (y-c) * (y+c);
        const double v2 = x * (y+c) + x * (y+c);

        return 1.0 / (v1 * v1 + v2 * v2);
    }
};

Plot::Plot(QWidget *parent):
    QwtPlot(parent)
{
    d_spectrogram = new QwtPlotSpectrogram();

    QwtLinearColorMap colorMap(Qt::darkCyan, Qt::red);
    colorMap.addColorStop(0.1, Qt::cyan);
    colorMap.addColorStop(0.6, Qt::green);
    colorMap.addColorStop(0.95, Qt::yellow);

    d_spectrogram->setColorMap(colorMap);

    d_spectrogram->setData(SpectrogramData());
    d_spectrogram->attach(this);

    QwtValueList contourLevels;
    for ( double level = 0.5; level < 10.0; level += 1.0 )
        contourLevels += level;
    d_spectrogram->setContourLevels(contourLevels);

    QwtScaleWidget *rightAxis = axisWidget(QwtPlot::yRight);
    rightAxis->setTitle("Intensity");
    rightAxis->setColorBarEnabled(true);
    rightAxis->setColorMap(d_spectrogram->data().range(),
        d_spectrogram->colorMap());

    setAxisScale(QwtPlot::yRight, 
        d_spectrogram->data().range().minValue(),
        d_spectrogram->data().range().maxValue() );
    enableAxis(QwtPlot::yRight);

    plotLayout()->setAlignCanvasToScales(true);
    replot();

    // LeftButton for the zooming
    // MidButton for the panning
    // RightButton: zoom out by 1
    // Ctrl+RighButton: zoom out to full size

    QwtPlotZoomer* zoomer = new QwtPlotZoomer(canvas());
#if QT_VERSION < 0x040000
    zoomer->setMousePattern(QwtEventPattern::MouseSelect2,
        Qt::RightButton, Qt::ControlButton);
#else
    zoomer->setMousePattern(QwtEventPattern::MouseSelect2,
        Qt::RightButton, Qt::ControlModifier);
#endif
    zoomer->setMousePattern(QwtEventPattern::MouseSelect3,
        Qt::RightButton);

    QwtPlotPanner *panner = new QwtPlotPanner(canvas());
    panner->setAxisEnabled(QwtPlot::yRight, false);
    panner->setMouseButton(Qt::MidButton);

    // Avoid jumping when labels with more/less digits
    // appear/disappear when scrolling vertically

    const QFontMetrics fm(axisWidget(QwtPlot::yLeft)->font());
    QwtScaleDraw *sd = axisScaleDraw(QwtPlot::yLeft);
    sd->setMinimumExtent( fm.width("100.00") );

    const QColor c(Qt::darkBlue);
    zoomer->setRubberBandPen(c);
    zoomer->setTrackerPen(c);
}

void Plot::showContour(bool on)
{
    d_spectrogram->setDisplayMode(QwtPlotSpectrogram::ContourMode, on);
    replot();
}

void Plot::showSpectrogram(bool on)
{
    d_spectrogram->setDisplayMode(QwtPlotSpectrogram::ImageMode, on);
    d_spectrogram->setDefaultContourPen(on ? QPen() : QPen(Qt::NoPen));
    replot();
}