check qwt-5.2, r588 into repository

qwt/examples/bode/bode_plot.h

@@ -0,0 +1,25 @@
+#include <qwt_plot.h>
+
+class QwtPlotCurve;
+class QwtPlotMarker;
+
+class BodePlot: public QwtPlot
+{
+    Q_OBJECT
+public:
+    BodePlot(QWidget *parent);
+
+public slots:
+    void setDamp(double damping);
+
+private:
+    void showData(double *frequency, double *amplitude, 
+        double *phase, int count);
+    void showPeak(double freq, double amplitude);
+    void show3dB(double freq);
+
+    QwtPlotCurve *d_crv1;
+    QwtPlotCurve *d_crv2;
+    QwtPlotMarker *d_mrk1;
+    QwtPlotMarker *d_mrk2;
+};