Qt中实时调取摄像头(含代码)

QT       += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
CONFIG += c++11
# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
SOURCES += \
    main.cpp \
    widget.cpp
HEADERS += \
    widget.h
FORMS += \
    widget.ui
# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target
INCLUDEPATH += D:\opencv450\opencv\build\include
INCLUDEPATH += D:\opencv450\opencv\build\include\opencv2
INCLUDEPATH += D:\opencv450\opencv\build\bin
INCLUDEPATH += D:\opencv450\opencv\newbuild\install\include
LIBS += -LD:\opencv450\opencv\newbuild\install\x64\mingw\bin\
        -llibopencv_calib3d450 \
        -llibopencv_core450 \
        -llibopencv_dnn450 \
        -llibopencv_features2d450 \
        -llibopencv_flann450 \
        -llibopencv_gapi450 \
        -llibopencv_highgui450 \
        -llibopencv_imgcodecs450 \
        -llibopencv_imgproc450 \
        -llibopencv_ml450 \
        -llibopencv_objdetect450 \
        -llibopencv_photo450 \
        -llibopencv_stitching450 \
        -llibopencv_video450 \
        -llibopencv_videoio450 \
        #-opencv_videoio_ffmpeg.dll \

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <opencv2/opencv.hpp>
#include <QTimer>
using namespace cv;
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
    Q_OBJECT
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
private slots:
    void on_pushButton_clicked();
    void video_update();
private:
    Ui::Widget *ui;
    Mat video_image;
    VideoCapture cap;
    QTimer *label_update;
    int flag = 0;
};
#endif // WIDGET_H

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

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>
#include <QTimer>
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    label_update = new QTimer(this);
    connect(label_update,&QTimer::timeout,this,&Widget::video_update);
}
Widget::~Widget()
{
    delete ui;
}
void Widget::on_pushButton_clicked()
{
    if (flag == 0){
        cap.open(0);
        label_update->start(30);
        flag++;
        ui->pushButton->setText("Close");
    }
    else{
        label_update->stop();
        cap.release();
        ui->label->clear();
        ui->pushButton->setText("Open");
        flag = 0;
    }
}
void Widget::video_update()
{
    cap >> video_image;
    cvtColor(video_image, video_image, COLOR_BGR2RGB);
    ui->label->setPixmap(QPixmap::fromImage(QImage(video_image.data,video_image.cols,video_image.rows,QImage::Format_RGB888)));
}