Qt第二十五天

亦凉 2022-04-02 19:42 217阅读 0赞

qwt绘制动态折线图  
mainwindow.h

#ifndef MAINWINDOW_H
    #define MAINWINDOW_H
    
    
    #include <QMainWindow>
    #include "qwt_plot_curve.h"
    #include <QTimer>
    #include <QTime>
    #include <QPainter>
    #include <qwt_legend.h>
    #include "qwt_plot_item.h"
    
    
    namespace Ui {
    class MainWindow;
    }
    
    
    class MainWindow : public QMainWindow
    {
        Q_OBJECT
    private:
        QwtPlotCurve *curve=new QwtPlotCurve("x-y");
        QwtPlotCurve *curve1=new QwtPlotCurve("a-b");
        double val[10]={3,5,8,6,2,8,6,9,1,5};
        double time[10]={0,1,2,3,4,5,6,7,8,9};
        double time1[20]={0};
        double val1[20]={0};
        QwtLegend *legend=new QwtLegend;
    
    
        void timerEvent(QTimerEvent *event);
    private slots:
        void  legendChecked( const QVariant &itemInfo, bool on );
    
    
    public:
        explicit MainWindow(QWidget *parent = 0);
        ~MainWindow();
    
    
    private:
        Ui::MainWindow *ui;
    };
    
    
    #endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
    #include "ui_mainwindow.h"
    
    
    MainWindow::MainWindow(QWidget *parent) :
        QMainWindow(parent),
        ui(new Ui::MainWindow)
    {
        ui->setupUi(this);
        curve->setSamples(time,val,9);
        curve->attach(ui->qwtPlot);
        curve->setPen(QColor(Qt::red),1);
        this->startTimer(1000);
        legend->setDefaultItemMode(QwtLegendData::Checkable);
        ui->qwtPlot->insertLegend(legend);
        connect( legend, SIGNAL( checked( const QVariant &, bool, int ) ),
                SLOT( legendChecked( const QVariant &, bool ) ) );
        for(int i=1;i<20;i++)
        {
            time1[i]=time1[i-1]+0.5;
        }
        for(int i=0;i<20;i++)
        {
            val1[i]=qrand()%10;
        }
        //curve1 ->setSamples(time1,val1,10);
        //curve1->attach(ui->qwtPlot);
    
    
    }
    
    
    MainWindow::~MainWindow()
    {
        delete ui;
    }
    /*void MainWindow::timerEvent(QTimerEvent *event)
    {
        for(int i=0;i<19;i++)
        {
            val1[i]=val1[i+1];
            time1[i]=time1[i+1];
        }
        time1[19]+=0.5;
        qsrand(QTime::currentTime().msec());
        val1[19]=qrand()%10;
        curve1->setSamples(time1,val1,9);
        curve1->attach(ui->qwtPlot);
        ui->qwtPlot->replot();
    }*/
    void MainWindow::timerEvent(QTimerEvent *event)
    {
        for(int i=0;i<9;i++)
        {
            val[i]=val[i+1];
            time[i]=time[i+1];
        }
        time[9]+=1;
        qsrand(QTime::currentTime().second());
        val[9]=qrand()%10-5;
        curve->setSamples(time,val,9);
        curve->attach(ui->qwtPlot);
        ui->qwtPlot->replot();
    }
    void MainWindow::legendChecked(const QVariant &itemInfo, bool on)
    {
        QwtPlotItem *item=ui->qwtPlot->infoToItem(itemInfo);
        if(item)
        {
            item->setVisible(on);
        }
        ui->qwtPlot->replot();
    }

运行结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RoZVJvb2tpZTE_size_16_color_FFFFFF_t_70]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RoZVJvb2tpZTE_size_16_color_FFFFFF_t_70]: /images/20220402/3d1f6ed528834e3b97824ffd05f66834.png