QT简单绘图

文章为本人在黑马网络视频的学习笔记“https://www.bilibili.com/video/BV1XW411x7NU?p=37”

widget.h文件
#ifndef WIDGET_H
#define WIDGET_H


#include 
#include 
#include 
#include 


namespace Ui {
     
class Widget;
}


class Widget : public QWidget
{
     
    Q_OBJECT


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


private:
    Ui::Widget *ui;
protected:
    void paintEvent(QPaintEvent *event);
};


#endif // WIDGET_H

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


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


Widget::~Widget()
{
     
    delete ui;
}
void Widget::paintEvent(QPaintEvent *event)
    QPainter p;
    p.begin(this);
    //背景图操作
    //p.drawPixmap(0,0,width(),height(),QPixmap("../Image/1.bmp"));
    p.drawPixmap(rect(),QPixmap("../Image/1.bmp"));
    //定义画笔
    QPen pen;
    pen.setWidth(5);//设置线宽
    pen.setColor(QColor(0,0,255));//设置颜色
    pen.setStyle(Qt::DashLine);//设置风格
    //画直线
    p.setPen(pen);
    p.drawLine(50,50,150,50);
    p.drawLine(50,50,50,150);
    p.drawLine(50,150,150,150);
    p.drawLine(150,50,150,150);
    QBrush brush;//定义画刷
    brush.setColor(Qt::red);
    brush.setStyle(Qt::Dense1Pattern);//注意不设定样式不填充
    p.setBrush(brush);
    //画矩形
    p.drawRect(200,200,50,200);
    //画圆
    p.drawEllipse(QPoint(160,160),50,50);
    p.end();


}