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#include <qapplication.h>
#include <qwt_plot.h>
#include <qwt_plot_marker.h>
#include <qwt_plot_curve.h>
#include <qwt_legend.h>
#include <qwt_data.h>
#include <qwt_text.h>
#include <qwt_math.h>
#include <math.h>
//-----------------------------------------------------------------
// simple.cpp
//
// A simple example which shows how to use QwtPlot and QwtData
//-----------------------------------------------------------------
class SimpleData: public QwtData
{
// The x values depend on its index and the y values
// can be calculated from the corresponding x value.
// So we dont need to store the values.
// Such an implementation is slower because every point
// has to be recalculated for every replot, but it demonstrates how
// QwtData can be used.
public:
SimpleData(double(*y)(double), size_t size):
d_size(size),
d_y(y)
{
}
virtual QwtData *copy() const
{
return new SimpleData(d_y, d_size);
}
virtual size_t size() const
{
return d_size;
}
virtual double x(size_t i) const
{
return 0.1 * i;
}
virtual double y(size_t i) const
{
return d_y(x(i));
}
private:
size_t d_size;
double(*d_y)(double);
};
class Plot : public QwtPlot
{
public:
Plot();
};
Plot::Plot()
{
setTitle("A Simple QwtPlot Demonstration");
insertLegend(new QwtLegend(), QwtPlot::RightLegend);
// Set axis titles
setAxisTitle(xBottom, "x -->");
setAxisTitle(yLeft, "y -->");
// Insert new curves
QwtPlotCurve *cSin = new QwtPlotCurve("y = sin(x)");
#if QT_VERSION >= 0x040000
cSin->setRenderHint(QwtPlotItem::RenderAntialiased);
#endif
cSin->setPen(QPen(Qt::red));
cSin->attach(this);
QwtPlotCurve *cCos = new QwtPlotCurve("y = cos(x)");
#if QT_VERSION >= 0x040000
cCos->setRenderHint(QwtPlotItem::RenderAntialiased);
#endif
cCos->setPen(QPen(Qt::blue));
cCos->attach(this);
// Create sin and cos data
const int nPoints = 100;
cSin->setData(SimpleData(::sin, nPoints));
cCos->setData(SimpleData(::cos, nPoints));
// 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 = 2 * pi
QwtPlotMarker *mX = new QwtPlotMarker();
mX->setLabel(QString::fromLatin1("x = 2 pi"));
mX->setLabelAlignment(Qt::AlignLeft | Qt::AlignBottom);
mX->setLabelOrientation(Qt::Vertical);
mX->setLineStyle(QwtPlotMarker::VLine);
mX->setLinePen(QPen(Qt::black, 0, Qt::DashDotLine));
mX->setXValue(2.0 * M_PI);
mX->attach(this);
}
int main(int argc, char **argv)
{
QApplication a(argc, argv);
Plot plot;
#if QT_VERSION < 0x040000
a.setMainWidget(&plot);
#endif
plot.resize(600,400);
plot.show();
return a.exec();
}
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