QT：绘图

news2024/11/27 21:02:05

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QPaintEvent>  //绘图事件

class Widget : public QWidget
{
    Q_OBJECT

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

    void paintEvent(QPaintEvent *event);  //重写绘图事件
    void timerEvent(QTimerEvent *event);
private:
    int xPos;  //x轴坐标
};

#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include <QPainter>  //画家
#include <QPen>   //画笔
#include <QBrush>   //画刷
#include <QTimerEvent>
#include <QDebug>

Widget::Widget(QWidget *parent)
    : QWidget(parent),xPos(0)   //x轴坐标初始化为0
{
    setWindowTitle("绘图");
    setFixedSize(1000,800);
    //QWidget自带一个定时器
    startTimer(1000);
}

Widget::~Widget()
{

}

//重写绘图事件
void Widget::paintEvent(QPaintEvent *event)
{
    //将widget主窗口作为画布
    QPainter painter(this);

    //设置画笔颜色为蓝色
    QPen pen(QColor(0,0,255));  //三基色：红绿蓝
    //设置画笔的粗细
    pen.setWidth(2);
    //设置画笔风格:点线
    pen.setStyle(Qt::DotLine);

    //设置画刷颜色为红色:填充
    QBrush brush(QColor(255,0,0));
   //设置画刷风格
    brush.setStyle(Qt::Dense6Pattern);

   painter.setPen(pen);
   painter.setBrush(brush);

   //画一条线，起始x轴y轴，终点x轴y轴
   painter.drawLine(0,0,100,100);
   //画矩形，起始x轴y轴，宽200高100
   painter.drawRect(100,100,200,100);
   //画圆
   painter.drawEllipse(400,100,100,100);
   //画椭圆
   painter.drawEllipse(500,100,400,100);

   //画浮点数的点
   const QPointF points[4] = {
       QPointF(10.1,80.2),
       QPointF(20.1,10.5),
       QPointF(70.6,40.7),
       QPointF(90.2,100.6)
   };
   //画多边形，多个点连接
   painter.drawPolygon(points,4);

   //画图片
   painter.drawPixmap(xPos++*50,400,QPixmap(":/images/luffy.png"));
   if(xPos*50 > this->width())   //图片移动
   {
       xPos = 0;
   }
}

void Widget::timerEvent(QTimerEvent *event)
{
    qDebug() << "超时事件";

    //手动刷新，让窗口重绘，产生绘图事件
    this->update();
}

mian.cpp

#include "widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

资源文件