[Qt]windows实时视频（Qt绘制Gui）

开篇先放一个很好的Qt5的学习链接：链接

这篇文章默认是你已经搭建好了windows和树莓派的Qt5的环境
Qt两个项目继承的基类都是Qwidget

本文用到的Qt知识有：
1、信号槽机制
2、Qt的网络编程
3、Qt的pushbutton，lable，textedit部件

我的学习一门语言或者一种语法的技巧就是学最精华的部分，学自己要用到的部分。现在学习的编程语言很多，也不可能去一个个细致的学习。掌握了最精华的部分就是关键！

涉及到两个程序，一个是Server，一个是Client

用到的模块有

Client.h

#ifndef CLIENT_H
#define CLIENT_H

#include 

#include 
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
using namespace cv;

namespace Ui {
class Client;
}

class Client : public QWidget
{
    Q_OBJECT

public:
    explicit Client(QWidget *parent = 0);
    ~Client();
    qint64 blockSize;

    QTcpSocket* tcpSocket;
    VideoCapture cap;
    QTimer* timer;

private slots:
    void displayError(QAbstractSocket::SocketError);
    void requestNewFortune();
    void enableGetFortuneButton();
    void SendData();

private:
    Ui::Client *ui;
};

#endif // CLIENT_H

Client.cpp

#include "client.h"
#include "ui_client.h"

Client::Client(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Client)
{
    ui->setupUi(this);

    ui->Fortune_ptn->setGeometry(100,330,80,80);
    ui->quit_ptn->setGeometry(360,330,80,80);
    tcpSocket=new QTcpSocket(this);
    timer=new QTimer(this);
    cap.open(0);

    if(!cap.isOpened()){
        QMessageBox::information(this,tr("提示"),tr("摄像头没有打开"));
    }

    connect(ui->Fortune_ptn,SIGNAL(clicked(bool)),this,SLOT(requestNewFortune()));
    connect(ui->quit_ptn,SIGNAL(clicked(bool)),this,SLOT(enableGetFortuneButton()));
    connect(timer,SIGNAL(timeout()),this,SLOT(SendData()));
    connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
}

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

void Client::displayError(QAbstractSocket::SocketError)
{
    qDebug()<<"传输失败！";
}

void Client::requestNewFortune()
{
    timer->start(30);
    ui->Fortune_ptn->setEnabled(true);
}

void Client::enableGetFortuneButton()
{
    ui->Fortune_ptn->setEnabled(true);
    tcpSocket->disconnectFromHost();
    timer->stop();
}

void Client::SendData()
{

    blockSize=0;
    tcpSocket->abort();
    tcpSocket->connectToHost(QHostAddress::LocalHost,8888);
    Mat frame;
    cap>>frame;
    cvtColor(frame,frame,CV_BGR2RGB);

    QByteArray byte;
    QBuffer buf(&byte);
    QImage image((unsigned const char*)frame.data,frame.cols,frame.rows,QImage::Format_RGB888);
    image.save(&buf,"JPEG");
    QByteArray ss=qCompress(byte,1);
    QByteArray vv=ss.toBase64();

    QByteArray ba;
    QDataStream out(&ba,QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_5_6);

    out<<(quint64)0;
    out<seek(0);
    out<<(quint64)(ba.size()-sizeof(quint64));
    tcpSocket->write(ba);
    ui->image_label->setGeometry(0,0,551,321);
    ui->image_label->setPixmap(QPixmap::fromImage(image));
    //ui->image_label->resize(image.size());

    update();

}

Server.h

#ifndef SERVER_H
#define SERVER_H

#include 
#include
#include
#include
#include
//#include
#include
#include

namespace Ui {
class Server;
}

class Server : public QWidget
{
    Q_OBJECT

public:
    explicit Server(QWidget *parent = 0);
    ~Server();

    QTcpServer *tcpServer;
    QTcpSocket *tcpServerConnection;
    QStringList *fortunes;
    QImage *img;
    quint64 basize;

public slots:
    void sendFortune();

    QByteArray GetPicData(QString fromPic);
    void DisplayError(QAbstractSocket::SocketError socketError);
    void ReadMyData();

    void ShowImage(QByteArray ba);


private:
    Ui::Server *ui;
};

#endif // SERVER_H

server.cpp

#include "server.h"
#include "ui_server.h"

Server::Server(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Server)
{
    ui->setupUi(this);
    tcpServer = new QTcpServer(this);
    if(!tcpServer->listen(QHostAddress::Any,8888))
    {
        QMessageBox::critical(this,tr("Fortune Server"),tr("Unable to start the server:%l.").arg(tcpServer->errorString()));
        close();
        return;
    }
    connect(tcpServer, SIGNAL(newConnection()), this, SLOT(sendFortune()));
}

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


void Server::sendFortune()
{
    basize=0;
    tcpServerConnection = tcpServer->nextPendingConnection();
    connect(tcpServerConnection,SIGNAL(readyRead()),this,SLOT(ReadMyData()));
    connect(tcpServerConnection,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(DisplayError(QAbstractSocket::SocketError)));

}
QByteArray Server::GetPicData(QString fromPic)
{
    QImage img(fromPic);
    QByteArray block;
    QBuffer buf(&block);
    img.save(&buf,"JPEG");//按照JPG解码保存数据
    QByteArray cc = qCompress(block,1);
    QByteArray hh;
    hh=cc.toBase64();//base64数据
    return hh;
}

void Server::DisplayError(QAbstractSocket::SocketError socketError)
{
    tcpServerConnection->close();
}
void Server::ReadMyData()
{
    QByteArray message;//存放从服务器接收到的字符串

    QDataStream in(tcpServerConnection);
    in.setVersion(QDataStream::Qt_5_6);
    if (basize==0)
    {
        //判断接收的数据是否有两字节（文件大小信息）
        //如果有则保存到basize变量中，没有则返回，继续接收数据
        if (tcpServerConnection->bytesAvailable()<(int)sizeof(quint64))
        {
            return;
        }
        in>>basize;
    }
    //如果没有得到全部数据，则返回继续接收数据
    if (tcpServerConnection->bytesAvailable()>message;//将接收到的数据存放到变量中
    ShowImage(message);
}

void Server::ShowImage(QByteArray ba)
{
    QString ss=QString::fromLatin1(ba.data(),ba.size());
    QByteArray rc;
    rc=QByteArray::fromBase64(ss.toLatin1());
    QByteArray rdc=qUncompress(rc);
    QImage img;
    img.loadFromData(rdc);
    ui->image_label->setGeometry(0,0,631,401);
    ui->image_label->setPixmap(QPixmap::fromImage(img));
    //ui->image_label->resize(img.size());
    update();
}

实验的结果：

可见是成功的！完成了监控。

期间遇到一些问题，在这里总结一下

这里是没有添加pushbutton部件，这里显示Client类没有这两个成员

这里是无效的类型，这里由于我的疏忽没有引入Qtimer头文件


这里没有引入Qbuffer头文件


以及一些奇怪的错误，原因在于没有引入network模块

参考博客：https://blog.csdn.net/u013812682/article/details/52185540