Qt + 线程 QImage

#ifndef MYTHREAD_H
#define MYTHREAD_H

#include <QObject>

#include <QImage>
class MyThread : public QObject
{
    Q_OBJECT
public:
    explicit MyThread(QObject *parent = 0);

    //线程处理函数
    void drawImage();

signals:
    void updateImage(QImage temp);

public slots:
};

#endif // MYTHREAD_H

#ifndef MYWIDGET_H
#define MYWIDGET_H

#include <QWidget>

#include "mythread.h"
#include <QThread>
namespace Ui {
class MyWidget;
}

class MyWidget : public QWidget
{
    Q_OBJECT

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

    //重写绘图事件
    void paintEvent(QPaintEvent *event);

    void getImage(QImage);//槽函数

    void dealClose();//窗口关闭槽函数

private:
    Ui::MyWidget *ui;

    QImage image;

    MyThread *myT;//自定义线程对象

    QThread *thread;
};

#endif // MYWIDGET_H

#include "mythread.h"

#include <QPoint>
#include <QPainter>
#include <QPen>
#include <QBrush>
MyThread::MyThread(QObject *parent) : QObject(parent)
{

}

void MyThread::drawImage()
{
    //定义QImage绘图设备
    QImage image(500,500,QImage::Format_ARGB32);

    //定义画家，指定绘图设备
    QPainter p(&image);

    //定义画笔对象
    QPen pen ;
    pen.setWidth(5);//设置宽度

    //把画笔交给画家
    p.setPen(pen);

    //定义画刷
    QBrush brush;
    brush.setStyle(Qt::SolidPattern);//设置样式
    brush.setColor(Qt::red);//设置颜色
    //把画刷交给画家
    p.setBrush(brush);

    //定义5个点
    QPoint a[] =
    {
        QPoint (qrand()%500,qrand()%500),
        QPoint (qrand()%500,qrand()%500),
        QPoint (qrand()%500,qrand()%500),
        QPoint (qrand()%500,qrand()%500),
        QPoint (qrand()%500,qrand()%500)

    };

    p.drawPolygon(a,5);

    //通过信号发送图片
    emit updateImage(image);


}

#include "mywidget.h"
#include "ui_mywidget.h"

#include <QPainter>
#include <QThread>
#include <QImage>

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

    //自定义类对象，分配空间，不可以指定父对象
    myT = new MyThread ;
    //创建子线程
    thread = new QThread(this);

    //将自定义模块添加到子线程
    myT->moveToThread(thread);

    //启动子线程，但是，并没有启动线程处理函数
    thread->start();

    //线程处理函数，必须通过sinal-slot调用
    connect(ui->pushButton,&QPushButton::pressed,myT,&MyThread::drawImage);

    connect(myT,&MyThread::updateImage,this,&MyWidget::getImage);


    connect( this,&MyWidget::destroyed,this,&MyWidget::dealClose);


}

MyWidget::~MyWidget()
{
    delete ui;

}
void MyWidget::dealClose()
{
    //退出子线程
    thread->quit();
    //回收资源
    thread->wait();
    delete myT;
}

void MyWidget::getImage(QImage temp)
{
    image = temp;
    update();//更新窗口，间接调用paintEvent
}



void MyWidget::paintEvent(QPaintEvent *event)
{
    QPainter p(this);//创建画家，指定 绘图设备为窗口

    p.drawImage(50,50,image);


}