QPaintDevice 绘图设备

1 QPixmap QImage Qbitmap(黑白色) QPicture QWidget

2 QPixmap 对不同平台做了显示优化  fill(填充颜色) QPainter paintere(&pic) 画家往设备上画 画完保存 save("路径")

3 QImage 可以对像素进行访问，和 QPixmap 差不多 对像素进行修改 img.setPixel();

4 Qpicture 记录和重现绘图指令。save 的时候可以上任意后缀名称 重现利用画家 painter.drawPicture();

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
Q_OBJECT

public:
Widget(QWidget *parent = nullptr);
~Widget();
protected:
void paintEvent(QPaintEvent * even);

private:
Ui::Widget *ui;
};
#endif // WIDGET_H

widght.cpp

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

Widget::Widget(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Widget)
{
ui->setupUi(this);
//绘画设备专门为为平台做显示优化的
QPixmap pixmap(300,300);
pixmap.fill(Qt::white);//填充颜色

QPainter painter(&pixmap);  
painter.setPen(QPen(Qt::green)); //设置绿色  
//在设备上画圆  
painter.drawEllipse(QPoint(100,100),100,100);//在点100，100 的位置画圆  
pixmap.save("/Users/libin/qtProject/painterDraw/pix.png");

 //////图片//////Qimag  
 QImage imag(300,300,QImage::Format\_ARGB32);  
 QPainter painter2(&imag);  
 painter2.setPen(QPen(Qt::red));  
 painter2.drawEllipse(QPoint(150,150),100,100);  
 imag.save("/Users/libin/qtProject/painterDraw/imag.png");

 ////QPictrue///////////绘图设备可以记录和重现绘图指令  
 QPicture picture;  
 QPainter painter4;  
 painter4.setPen(QPen(Qt::red));  
 painter4.begin(&picture); //开始往设备上画  
 painter4.drawEllipse(QPoint(20,20),200,200);  
 painter4.end();//结束  
 picture.save("/Users/libin/qtProject/paintDevice/pic.zt");

}
void Widget::paintEvent(QPaintEvent *even){
QImage img;
img.load(":/mm.png");
QPainter painter3(this);
for(int i =0;i<200;++i){
for(int j = 0;j<200;++j){
QRgb rbg = qRgb(255,i,j);
img.setPixel(i,j,rbg);
}
}
painter3.drawImage(0,0,img);

//读取画笔指令  
QPainter q5(this);  
QPicture picture3;  
picture3.load("/Users/libin/qtProject/paintDevice/pic.zt");  
q5.drawPicture(0,0,picture3);

}

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