check qwt-5.2, r588 into repository

qwt/examples/simple_plot/simple.cpp

@@ -0,0 +1,125 @@
+#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 don´t 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(); 
+}