Qt 多线程

qt中多线程使用示例：

.h文件:
#ifndef CTHREAD_H
#define CTHREAD_H

#include <QThread>
#include <QImage>

class CThread : public QThread
{
    Q_OBJECT
public:
    CThread();
    void setMessage(QString message);
    void stop();
    void SetImage(const QImage& img);
    QImage& GetShowImage();
protected:
    void run(); 
    void printMessage();
    void CreateShowImage();
private:
    QString messageStr;
    QImage m_image;
    QImage m_showImage;
    volatile bool stopped;

};

#endif // CTHREAD_H

.cpp文件：

#include "CThread.h"
#include <QDebug>
#include <QPainter>

CThread::CThread()
{
     stopped = false;
}

void CThread::run()
{
    while(!stopped)
   {
        CreateShowImage();
    }
    stopped = false;
}

void CThread::stop()
{
    stopped = true;
}

void CThread::setMessage(QString message)
{
    messageStr = message;
}

void CThread::printMessage()
{
    qDebug()<<messageStr;
    sleep(1);
}

QImage& CThread::GetShowImage()
{
    return m_showImage;
}

void CThread::SetImage( const QImage& img )
{
    m_image = img;
}

void CThread::CreateShowImage()
{
    int nWidth = m_image.width();
    int nHeight = m_image.height();

    if (nWidth <=0||nHeight<=0)
    {
        //stopped = true;
        return;
    }

    m_showImage = QImage(3*nWidth,3*nHeight,QImage::Format_ARGB32);
    QPainter painter(&m_showImage);
    QPixmap pixmap;
    pixmap.convertFromImage(m_image);

    for (int i=0;i<3;++i)
    {
        painter.drawPixmap(0+i*nWidth,0,pixmap);
        painter.drawPixmap(0+i*nWidth,nHeight,pixmap);
        painter.drawPixmap(0+i*nWidth,2*nHeight,pixmap);
    }

    //stopped = true;
}