linux qt调用摄像头,Qt5下实现摄像头预览及捕获图像方法实例

Step4:修改mainwindow.cpp

源码如下

#include "mainwindow.h"

#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :

QMainWindow(parent),

ui(new Ui::MainWindow)

{

ui->setupUi(this);

camera=new QCamera(this);

viewfinder=new QCameraViewfinder(this);

imageCapture=new QCameraImageCapture(camera);

ui->ImageView->addWidget(viewfinder);

ui->ImageCapture->setScaledContents(true);

camera->setViewfinder(viewfinder);

camera->start();

connect(imageCapture, SIGNAL(imageCaptured(int,QImage)), this, SLOT(displayImage(int,QImage)));

connect(ui->buttonCapture, SIGNAL(clicked()), this, SLOT(captureImage()));

connect(ui->buttonSave, SIGNAL(clicked()), this, SLOT(saveImage()));

connect(ui->buttonQuit, SIGNAL(clicked()), qApp, SLOT(quit()));

}

MainWindow::~MainWindow()

{

delete ui;

}

void MainWindow::captureImage()

{

ui->statusBar->showMessage(tr("capturing..."), 1000);

imageCapture->capture();

}

void MainWindow::displayImage(int , QImage image)

{

ui->ImageCapture->setPixmap(QPixmap::fromImage(image));

ui->statusBar->showMessage(tr("capture OK!"), 5000);

}

void MainWindow::saveImage()

{

QString fileName=QFileDialog::getSaveFileName(this, tr("save file"), QDir::homePath(), tr("jpegfile(*.jpg)"));

if(fileName.isEmpty()) {

ui->statusBar->showMessage(tr("save cancel"), 5000);

return;

}

const QPixmap* pixmap=ui->ImageCapture->pixmap();

if(pixmap) {

pixmap->save(fileName);

ui->statusBar->showMessage(tr("save OK"), 5000);

}

}

Step5：编译工程效果如下

总结：QCamera类封装了很多底层操作，为了更进一步地了解Linux下摄像头的调用机制，我将在后续探讨V4L2及ioctl操作摄像头的机理。

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