check qwt-5.2, r588 into repository

qwt/examples/realtime_plot/randomplot.cpp

@@ -0,0 +1,124 @@
+#include <stdlib.h>
+#include <qtimer.h>
+#include <qwt_plot_grid.h>
+#include <qwt_plot_canvas.h>
+#include <qwt_plot_layout.h>
+#include <qwt_scale_widget.h>
+#include <qwt_scale_draw.h>
+#include "scrollzoomer.h"
+#include "randomplot.h"
+
+const unsigned int c_rangeMax = 1000;
+
+class Zoomer: public ScrollZoomer
+{
+public:
+    Zoomer(QwtPlotCanvas *canvas):
+        ScrollZoomer(canvas)
+    {
+    }
+
+    virtual void rescale()
+    {
+        QwtScaleWidget *scaleWidget = plot()->axisWidget(yAxis());
+        QwtScaleDraw *sd = scaleWidget->scaleDraw();
+
+        int minExtent = 0;
+        if ( zoomRectIndex() > 0 )
+        {
+            // When scrolling in vertical direction
+            // the plot is jumping in horizontal direction
+            // because of the different widths of the labels
+            // So we better use a fixed extent.
+
+            minExtent = sd->spacing() + sd->majTickLength() + 1;
+            minExtent += sd->labelSize(
+                scaleWidget->font(), c_rangeMax).width();
+        }
+
+        sd->setMinimumExtent(minExtent);
+
+        ScrollZoomer::rescale();
+    }
+};
+
+RandomPlot::RandomPlot(QWidget *parent):
+    IncrementalPlot(parent),
+    d_timer(0),
+    d_timerCount(0)
+{
+    setFrameStyle(QFrame::NoFrame);
+    setLineWidth(0);
+    setCanvasLineWidth(2);
+
+    plotLayout()->setAlignCanvasToScales(true);
+
+    QwtPlotGrid *grid = new QwtPlotGrid;
+    grid->setMajPen(QPen(Qt::gray, 0, Qt::DotLine));
+    grid->attach(this);
+
+    setCanvasBackground(QColor(29, 100, 141)); // nice blue
+
+    setAxisScale(xBottom, 0, c_rangeMax);
+    setAxisScale(yLeft, 0, c_rangeMax);
+    
+    replot();
+
+    // enable zooming
+
+    Zoomer *zoomer = new Zoomer(canvas());
+    zoomer->setRubberBandPen(QPen(Qt::red, 2, Qt::DotLine));
+    zoomer->setTrackerPen(QPen(Qt::red));
+}
+
+QSize RandomPlot::sizeHint() const
+{
+    return QSize(540,400);
+}
+
+void RandomPlot::appendPoint()
+{
+    double x = rand() % c_rangeMax;
+    x += ( rand() % 100 ) / 100;
+
+    double y = rand() % c_rangeMax;
+    y += ( rand() % 100 ) / 100;
+
+    appendData(x, y);
+
+    if ( --d_timerCount <= 0 )
+        stop();
+}
+
+void RandomPlot::append(int timeout, int count)
+{
+    if ( !d_timer )
+    {
+        d_timer = new QTimer(this);
+        connect(d_timer, SIGNAL(timeout()), SLOT(appendPoint()));
+    }
+
+    d_timerCount = count;
+
+    emit running(true);
+
+    canvas()->setPaintAttribute(QwtPlotCanvas::PaintCached, false);
+    d_timer->start(timeout);
+}
+
+void RandomPlot::stop()
+{
+    if ( d_timer )
+    {
+        d_timer->stop();
+        emit running(false);
+    }
+
+    canvas()->setPaintAttribute(QwtPlotCanvas::PaintCached, true);
+}
+
+void RandomPlot::clear()
+{
+    removeData();
+    replot();
+}