Qt调用摄像头（截取并保存图片）

Qt如何调用系统摄像设备进行显示、截图、录制？
QCamera：系统摄像设备（摄像头）
QCameraViewfinder：摄像取景器部件
QCameraImageCapture：截图部件
capture按钮：用于截图（截图后在右上角显示）
save按钮：用于保存截取后的图片（此处测试路径为：F:\a.jpg）
exit按钮：退出界面

效果如下：



代码如下：

#include "test_capture.h"

Dialog::Dialog(QWidget *parent) :
QDialog(parent)
{
this->resize(600, 400);

camera = new QCamera();
view_finder = new QCameraViewfinder();
camera_image_capture = new QCameraImageCapture(camera);
capture_button = new QPushButton();
save_button = new QPushButton();
exit_button = new QPushButton();
display_label = new QLabel();

QHBoxLayout *main_layout = new QHBoxLayout();
QVBoxLayout *v_layout = new QVBoxLayout();

display_label->setFixedSize(150, 150);
display_label->setScaledContents(true);

v_layout->addWidget(display_label);
v_layout->addStretch();
v_layout->addWidget(capture_button);
v_layout->addWidget(save_button);
v_layout->addWidget(exit_button);

main_layout->addWidget(view_finder);
main_layout->addLayout(v_layout);

connect(capture_button, &QPushButton::clicked, this, &Dialog::captureImage);
connect(save_button, &QPushButton::clicked, this, &Dialog::saveImage);
connect(exit_button, &QPushButton::clicked, this, &Dialog::close);
connect(camera_image_capture, &QCameraImageCapture::imageCaptured, this, &Dialog::displayImage);

camera_image_capture->setCaptureDestination(QCameraImageCapture::CaptureToFile);
camera->setCaptureMode(QCamera::CaptureStillImage);
camera->setViewfinder(view_finder);
camera->start(); //启动摄像头

this->setLayout(main_layout);
this->translateLanguage();
}

Dialog::~Dialog()
{

}

void Dialog::translateLanguage()
{
this->setWindowTitle("testCapture");
capture_button->setText(tr("capture"));
save_button->setText(tr("save"));
exit_button->setText(tr("exit"));
}

void Dialog::displayImage(int id, QImage image)
{
display_label->setPixmap(QPixmap::fromImage(image));
}

void Dialog::captureImage()
{
//截图
camera_image_capture->capture();
}

void Dialog::saveImage()
{
const QPixmap *pixmap = display_label->pixmap();
if(pixmap)
{
pixmap->save("F:\\a.jpg");
}
}