在Linux系统下QT获取摄像头图像，显示在对应窗口

快来打我* 2022-12-27 02:26 224阅读 0赞

在Linux系统下，通过QT对multimedia、multimediawidgets库的使用，打开摄像头获取图像并显示在对应窗口，点击指定按钮时实现截图保存与显示。

[完整工程代码：https://download.csdn.net/download/weixin\_43793181/20325195][https_download.csdn.net_download_weixin_43793181_20325195]

界面效果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc5MzE4MQ_size_16_color_FFFFFF_t_70]  
  
  
mycamera.h

#ifndef MYCAMERA_H
    #define MYCAMERA_H
    
    #include <QWidget>
    #include <QCameraInfo>
    #include <QCamera>
    #include <QVideoWidget>
    #include <QCameraViewfinder>
    #include <QCameraImageCapture>
    
    QT_BEGIN_NAMESPACE
    namespace Ui {  class MyCamera; }
    QT_END_NAMESPACE
    
    class MyCamera : public QWidget
    { 
        Q_OBJECT
    
    public:
        MyCamera(QWidget *parent = nullptr);
        ~MyCamera();
    
    private slots:
        void on_pushButton_start_clicked();
    
        void on_pushButton_stop_clicked();
    
        void on_pushButton_capture_clicked();
        //显示图片
        void show_pic(int id, const QImage &preview);
    
    private:
        Ui::MyCamera *ui;
        QCamera *ca;//摄像头对象
        //QVideoWidget *w;
        QCameraViewfinder *w;
        QCameraImageCapture *cap;//截屏对象
    };
    #endif // MYCAMERA_H

mycamera.cpp

#include "mycamera.h"
    #include "ui_mycamera.h"
    #include <QDebug>
    #include <QDir>
    
    MyCamera::MyCamera(QWidget *parent)
        : QWidget(parent)
        , ui(new Ui::MyCamera)
    { 
        ui->setupUi(this);
    
        //获取系统中可用的摄像头信息
        QList<QCameraInfo> infos = QCameraInfo::availableCameras();
        //显示到下拉列表
        foreach(QCameraInfo info,infos){ 
            qDebug()<<info.deviceName()<<info.description();
            //把摄像头设备名加入列表
            ui->comboBox->addItem(info.deviceName());
        }
    
        ui->pushButton_stop->setEnabled(false);
        ui->pushButton_capture->setEnabled(false);
    }
    
    MyCamera::~MyCamera()
    { 
        delete ui;
    }
    
    //开始
    void MyCamera::on_pushButton_start_clicked()
    { 
        //构造摄像头对象
        ca = new QCamera(ui->comboBox->currentText().toUtf8(),this);
        //构造截屏对象
        cap = new QCameraImageCapture(ca,this);
    
        //连接截屏信号和显示截屏图像的槽
        QObject::connect(cap,&QCameraImageCapture::imageCaptured,this,&MyCamera::show_pic);
    
    #if 0
        //使用父类对象构造显示窗口类
        w = new QVideoWidget(ui->widget);
    
    #else
        w = new QCameraViewfinder(ui->widget);
    
    #endif
        //调整大小一致
        w->resize(ui->widget->size());
    
        //设置摄像头的显示窗口
        ca->setViewfinder(w);
        w->show();
    
        //启动摄像头
        ca->start();
    
        //禁止开始按钮
        ui->pushButton_start->setEnabled(false);
        ui->pushButton_stop->setEnabled(true);
        ui->pushButton_capture->setEnabled(true);
    }
    
    //停止
    void MyCamera::on_pushButton_stop_clicked()
    { 
        //停止摄像头
        ca->stop();
        //隐藏显示窗口
        w->hide();
    
        //断开信号
        QObject::disconnect(cap,&QCameraImageCapture::imageCaptured,this,&MyCamera::show_pic);
    
        delete w;
        delete cap;
        delete ca;
    
        ui->pushButton_start->setEnabled(true);
        ui->pushButton_stop->setEnabled(false);
        ui->pushButton_capture->setEnabled(false);
    }
    
    //截屏
    void MyCamera::on_pushButton_capture_clicked()
    { 
        cap->capture();
        //不能立即显示图片
    }
    
    //显示截屏图片
    void MyCamera::show_pic(int id, const QImage &preview)
    { 
        qDebug()<<id;
        //把QImage转换成QPixmap
        QPixmap pix = QPixmap::fromImage(preview);
    
        //保存图片
        QString picpath = QString("./%1.jpg").arg(id);
        pix.save(picpath);
    
        //显示
        pix = pix.scaled(ui->label->size());
        ui->label->setPixmap(pix);
    }

main.cpp

#include "mycamera.h"
    
    #include <QApplication>
    
    int main(int argc, char *argv[])
    { 
        QApplication a(argc, argv);
        MyCamera w;
        w.show();
        return a.exec();
    }

[完整工程代码：https://download.csdn.net/download/weixin\_43793181/20325195][https_download.csdn.net_download_weixin_43793181_20325195]

[https_download.csdn.net_download_weixin_43793181_20325195]: https://download.csdn.net/download/weixin_43793181/20325195
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc5MzE4MQ_size_16_color_FFFFFF_t_70]: /images/20221120/14b5cf8775fd45adb11ba5139b35a944.png