QPicture#include "widget.#include "ui_widget.p.p.drawPixmap(

#include "widget.h"
#include "ui_widget.h"
#include<QPainter>
#include<QPicture>

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

    QPicture picture;
    QPainter p;
    p.begin(&picture);

    p.drawPixmap(0,0,80,80,QPixmap("../image/路飞.jpg"));
    p.drawLine(50,50,150,50);

    p.end();
    //保存的是二进制文件
    picture.save("../picture.jpg");
}

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

void Widget::paintEvent(QPaintEvent *)
{
    QPicture pic;//把二进制文件加载出来
    pic.load("../picture.jpg");

    QPainter p(this);
    p.drawPicture(0,0,pic);
}