【米尔-芯驰D9360商显板试用评测】创建视频监控

1、使用ui创建一个普通的桌面，放入两个Qcombox,一个按键，UI如下：

2、在.pro中添回摄像头的引用：
QT += multimedia multimediawidgets
3、mainwindows.h文件内容如下：

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>


QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class QCamera;
class QCameraViewfinder;
class QCameraImageCapture;
class QCameraInfo;
class QCameraViewfinderSettings;

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
    QCamera *camera;                   //相机
    QCameraViewfinder *viewfinder;     //取景器
    QCameraImageCapture *imageCapture; //图像捕获
    QList<QCameraInfo> cameras;        //相机列表
    QList<QSize> mResSize = {};        //分辨率列表


};
#endif // MAINWINDOW_H

4、mainwindos.cpp内容如下：

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QCamera>
#include <QCameraInfo>
#include <QCameraViewfinder>
#include <QCameraImageCapture>
#include <QFileDialog>
#include <QList>
#include <QDebug>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    setWindowTitle("Camera");
    setFixedSize(600,400);

    cameras = QCameraInfo::availableCameras();   //获取所有相机的列表
    //qDebug() << "this is camera: ";
    if (cameras.count() > 0) {
        for(const QCameraInfo &cameraInfo:cameras) {
            qDebug() << cameraInfo.description();
        }
        camera = new QCamera(cameras.at(0));     //初始化实例化一个相机对象
    }

    //设置取景器
    viewfinder = new QCameraViewfinder(this);
    camera->setViewfinder(viewfinder);
    viewfinder->resize(600,350);                 //设置取景器显示大小
    //viewfinder->show();

    imageCapture = new QCameraImageCapture(camera);
    camera->start();                             //开启相机

    //设置默认摄像头参数
    QCameraViewfinderSettings set;
    set.setResolution(640, 480);                 //设置显示分辨率
    set.setMaximumFrameRate(60);                 //设置帧率
    camera->setViewfinderSettings(set);

    //添加初始化的相机选项
    for(const QCameraInfo &cameraInfo:cameras) {
        qDebug() << "CameraInfo:" << cameraInfo;
        ui->cameraSel->addItem(cameraInfo.description());
    }
    ui->cameraSel->setCurrentIndex(0);

    //添加初始化相机的分辨率选项
    mResSize = camera->supportedViewfinderResolutions();
    //qDebug() << "mResSize = " << mResSize;
    for (const QSize &msize:mResSize) {
           qDebug() << msize; //摄像头支持分辨率打印
           ui->resolutionSel->addItem(QString::number(msize.width(), 10) + "*" + QString::number(msize.height(), 10));
    }
    ui->resolutionSel->setCurrentIndex(0);
    //信号槽连接
        connect(ui->cameraSel, QOverload<int>::of(&QComboBox::activated), [=](int index){
            //qDebug() << "Index" << ui->cameraSel->currentIndex() << ": " << ui->cameraSel->currentText();
            camera->stop();
            delete camera;
            camera = new QCamera(cameras[index]);                //camera指向指定的摄像头
            camera->setCaptureMode(QCamera::CaptureStillImage);  //设定捕获模式
            camera->setViewfinder(viewfinder);                   //设置取景器
            camera->start();

            //删除前相机的所有分辨率内容
            for (int i = 0; i < mResSize.size(); i++) {
                   ui->resolutionSel->removeItem(0);
            }

            //添加新相机的所有分辨率
            mResSize.clear();
            //qDebug() << "now mResSize = " << mResSize;
            mResSize = camera->supportedViewfinderResolutions();
            for (const QSize &msize:mResSize) {
                   qDebug() << msize; //摄像头支持分辨率打印
                   ui->resolutionSel->addItem(QString::number(msize.width(), 10) + "*" + QString::number(msize.height(), 10));
            }
            ui->resolutionSel->setCurrentIndex(0);
        });

        connect(ui->resolutionSel, QOverload<int>::of(&QComboBox::activated), [=](int index){
            //qDebug() << "Index" << ui->resolutionSel->currentIndex() << ": " << ui->resolutionSel->currentText();
            //qDebug() << "mResSize:" << mResSize[index];
            //重新设置摄像头参数
            QCameraViewfinderSettings reset;
            reset.setResolution(mResSize[index]);
            camera->setViewfinderSettings(reset);
        });

        connect(ui->screenShot, &QPushButton::clicked, [=](){
            camera->setCaptureMode(QCamera::CaptureStillImage);
            delete imageCapture;
            imageCapture = new QCameraImageCapture(camera);
            QString fileName = QFileDialog::getSaveFileName();
            camera->searchAndLock();
            imageCapture->capture(fileName);
            camera->unlock();
        });


}

MainWindow::~MainWindow()
{
    delete ui;
}

具体的代码见注释。
5、编译下载到开发板，效果如下！