qt Qimage动态更改图片像素例子

      #include "widget.h"
#include "ui_widget.h"

#include <QPainter>
#include <QTimer>
#include "QDebug"

int i;
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    m_Image = QImage(200,200,QImage::Format_RGB32);
    QColor backColor = qRgb(255,255,0);    //画布初始化背景色使用白色
    m_Image.fill(backColor);//对画布进行填充
    m_Image2.fill(QColor(255,255,255));
    time = new QTimer(this);
    connect(time,SIGNAL(timeout()),this,SLOT(change()));
    for(int i = 0;i<=1301;++i)
    {
        m_vector.append(i);
    }


}

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

void Widget::on_pushButton_clicked()
{
    time->start(500);

}

void Widget::change()
{
    QRgb value;
    value = qRgb(255,0,0);
    for(int j =0;j<200;++j)
    {
        m_Image.setPixel(j,i,value);
        this->update();
    }
    ++i;
}
//传入采样集合 acc 为取样精度
template <typename T>
QVector<T> Widget::transf(QVector<T> &vector,const  int acc)
{
    QVector<T> newVec;
    newVec.reserve(vector.length()/acc);
    auto it = vector.begin();
    for (it ; vector.end()-it >acc; it+=acc)
    {
        auto max = std::max_element(it, it+acc);
        newVec.push_back(*max);
    }
    return newVec;
}


void Widget::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);

    painter.drawImage(0,0,m_Image);
    painter.drawImage(250,0,m_Image2);

}

void Widget::on_pushButton_2_clicked()
{
    time->stop();
    qDebug()<<transf(m_vector,4);
}

void Widget::on_pushButton_3_clicked()
{
    m_Image2 = m_Image;
    update();
    for(int i =0;i<200;++i)
    {
        arr[i] = 0.523*i;
        qDebug()<<arr[i];
    }
    qDebug()<<"转换了";
    QVector<float> vec= charToVect(arr);
    qDebug()<<vec;
}

template <typename T>
QVector<T> Widget::charToVect(T* arr)
{
    for(int i; i<200; ++i)
    {
        m_vectorf.append(arr[i]);
    }
    qDebug()<<m_vectorf.length();
    return m_vectorf;
}