Qt/QT_Assistant/camera/widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QGuiApplication>
#include <QScreen>
#include <QFile>
#include <QPixmap>
#include <QBuffer>
#include "camera.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    /* 摄像头 */
    camera = new Camera(this);
    scanCameraDevice();

    /* 信号连接槽 */
    connect(camera, SIGNAL(readyImage(QImage)),
            this, SLOT(showImage(QImage)));

    connect(ui->cam_traBut,SIGNAL(clicked(bool)),
            camera, SLOT(cameraProcess(bool)));//开启摄像头

    connect(ui->cam_playBut, SIGNAL(clicked()),
            this, SLOT(saveImageToLocal()));

}

Widget::~Widget()
{
    delete ui;
}
void Widget::scanCameraDevice()
{
    /* QFile文件指向/dev/video1 */
    QFile file("/dev/video1");

    file.setFileName("/dev/video1");

    if (file.exists())
    {
     qDebug()<<"camera success"  ;
     camera->selectCameraDevice(1);//video1
    }
    else
    {
      qDebug()<<"camera cannot finded" ;
    }
}
void Widget::showImage(const QImage &image)
{
    /* 显示图像 */
    ui->displayLabel->setPixmap(QPixmap::fromImage(image));
    saveImage = image;

    /* 判断图像是否为空，空则设置拍照按钮不可用 */
    if (!saveImage.isNull())
        ui->cam_playBut->setEnabled(true);
    else
        ui->cam_playBut->setEnabled(false);
}

void Widget::saveImageToLocal()
{
    /* 判断图像是否为空 */
    if (!saveImage.isNull()) {
        QString fileName =
                QCoreApplication::applicationDirPath() + "/test.png";
        qDebug()<<"正在保存"<<fileName<<"图片,请稍候..."<<endl;

        /* save(arg1，arg2，arg3)重载函数，arg1代表路径文件名，
         * arg2保存的类型，arg3代表保存的质量等级 */
        saveImage.save(fileName, "PNG", 1);

        /* 设置拍照的图像为显示在photoLabel上 */
        ui->cam_albumBut->setPixmap(QPixmap::fromImage(QImage(fileName)));

        qDebug()<<"保存完成！"<<endl;
    }
}