用qwt绘制按秒采集数据波形图

源码：

#ifndef MYWIDGET_H

#define MYWIDGET_H

#include <QWidget>

#include <qwt_plot_zoomer.h>

#include <QTimer>

#include <qwt_plot_curve.h>

#include <QDateTime>

#include <qwt_scale_draw.h>

#include <qwt_legend.h>

#include <qwt_scale_widget.h>

namespace Ui {

    class myWidget;

}

class myWidget : public QWidget

{

    Q_OBJECT

public:

    explicit myWidget(QWidget *parent = 0);

    ~myWidget();

private:

    Ui::myWidget *ui;

    QwtPlotCurve *p_adplot;

    QTimer *PlotTimer;

    QPolygonF points;

    int xMaxScale;

public slots:

    void plotCurve();

};

#endif // MYWIDGET_H

头文件中主要设置变量名以及自定义一个槽函数很简单的

.cpp文件

#include "mywidget.h"
#include "ui_mywidget.h"
class TimeScaleDraw: public QwtScaleDraw
{
public:
    TimeScaleDraw()
    {
    }
    virtual QwtText label( double v ) const
    {
        QDateTime dt;
        dt.setTime_t((int)v);
        return dt.toString("yyyy-MM-dd\n hh:mm:ss");
    }
private:
    QDateTime baseTime;
};
myWidget::myWidget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::myWidget)
{
    ui->setupUi(this);
    ui->qwtPlot->insertLegend(new QwtLegend, QwtPlot::RightLegend);
    ui->qwtPlot->setAxisTitle(QwtPlot::xBottom, " System Uptime[yyyy-MM-dd\n hh:mm:ss]");
    ui->qwtPlot->setAxisScaleDraw(QwtPlot::xBottom,new TimeScaleDraw());
    ui->qwtPlot->setAxisScale(QwtPlot::xBottom, QDateTime::currentDateTime().toTime_t()-5, xMaxScale = QDateTime::currentDateTime().toTime_t());
    ui->qwtPlot->setAxisLabelAlignment(QwtPlot::xBottom, Qt::AlignHCenter | Qt::AlignBottom);
    ui->qwtPlot->canvas()->setFrameStyle( QFrame::NoFrame | QFrame::Plain );
    ui->qwtPlot->setCanvasBackground(Qt::blue);
    ui->qwtPlot->setTitle ("按秒采集数据波形图");
    QwtScaleWidget *scaleWidget = ui->qwtPlot->axisWidget(QwtPlot::xBottom);//设置坐标边距
    const int fmh = QFontMetrics(scaleWidget->font()).height();
    scaleWidget->setMinBorderDist(0, fmh / 2);
    ui->qwtPlot->setAxisTitle(QwtPlot::yLeft, "V");
    ui->qwtPlot->setAxisScale(QwtPlot::yLeft, 0, 3);
    p_adplot = new QwtPlotCurve("AD模拟采集");
    QColor c = Qt::red;
    p_adplot->setPen(c);
    p_adplot->attach(ui->qwtPlot);
    QwtPlotZoomer* zoomer = new QwtPlotZoomer( ui->qwtPlot->canvas() );
    zoomer->setRubberBandPen( QColor( Qt::black ) );
    zoomer->setTrackerPen( QColor( Qt::black ) );
    zoomer->setMousePattern(QwtEventPattern::MouseSelect2,Qt::RightButton, Qt::ControlModifier );
    zoomer->setMousePattern(QwtEventPattern::MouseSelect3,Qt::RightButton );
    //qDebug()<<QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss")+"fir";
    PlotTimer = new QTimer();
    connect(PlotTimer, SIGNAL(timeout()),this, SLOT(plotCurve()));
    PlotTimer->start(1000);
}
void myWidget::plotCurve()
{
    ui->qwtPlot->setAxisScale(QwtPlot::xBottom, QDateTime::currentDateTime().toTime_t()-5, xMaxScale = QDateTime::currentDateTime().toTime_t());
    //qDebug()<<QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss")+"sec";
    points<<QPointF(QDateTime::currentDateTime().toTime_t(),rand()%3);
    p_adplot->setSamples(points);
    p_adplot->attach(ui->qwtPlot);
    ui->qwtPlot->replot();
}
myWidget::~myWidget()
{
    delete ui;
}