Qt之生成png/jpg/bmp格式图片

一、问题描述

有时候需要把Qt绘制的一些图形保存为png/jpg/bmp格式的图片，下面就根据自己写的一个简单的测试程序来讲解一下Qt中保存图片的方法。本文主要讲解使用Qpainter和QImage组合使用保存图片的方法。

二、显示效果

1、界面显示效果：

2、生成的图片及图片显示效果：

三、核心代码示例

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

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setWindowTitle("测试绘制图片并保存为png/jpg/bmp格式");
    drawPicture();
}

Widget::~Widget()
{
    delete ui;

}

/// 重写绘制事件，显示在widgt上面
void Widget::paintEvent(QPaintEvent *event)
{
    Q_UNUSED(event);
    QPainter *painter = new QPainter(this);
    painter->save();
    QPen pen;
    pen.setWidth(2);
    pen.setColor(Qt::red);
    painter->setPen(pen);
    painter->drawEllipse(QPoint(width()/2,height()/2),50,50);
    painter->drawLine(QPointF(0,0),QPointF(width()/2,height()/2));
    painter->drawRect(QRect(40,40,150,160));
    painter->restore();
    painter->end();
}

/// 绘制图片中
void Widget::drawPicture()
{
    QImage image(QSize(this->width(),this->height()),QImage::Format_ARGB32);
    image.fill("white");
    QPainter *painter = new QPainter(&image);
    painter->save();
    QPen pen;
    pen.setWidth(2);
    pen.setColor(Qt::red);
    painter->setPen(pen);
    painter->drawEllipse(QPoint(width()/2,height()/2),50,50);
    painter->drawLine(QPointF(0,0),QPointF(width()/2,height()/2));
    painter->drawRect(QRect(40,40,150,160));
    painter->restore();
    painter->end();
    m_image = image;
}

/// 保存为图片
void Widget::savePicture(const QString fileName, const char *format)
{
    m_image.save(fileName,format);
}

说明：源码下载地址：http://download.csdn.net/download/toby54king/10170570