绘图事件
#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = nullptr);
~Widget();
//绘图事件
void paintEvent(QPaintEvent *);
private:
Ui::Widget *ui;
};
#endif // WIDGET_H
#include "widget.h"
#include "ui_widget.h"
#include <QPainter>
#include <QBrush>
Widget::Widget(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Widget)
{
ui->setupUi(this);
}
//绘图事件
void Widget::paintEvent(QPaintEvent *)
{
//实例化画家类 this指定的是绘图的设备
QPainter painter(this);
//设置画笔
QPen pen(QColor(255,0,0));
//设置画笔宽度
pen.setWidth(3);
//设置画笔风格
pen.setStyle(Qt::DotLine);
//让画家使用这个笔
painter.setPen(pen);
//设置画刷
//QBrush brush(QColor(0,255,0));
QBrush brush(Qt::green);
//设置画刷风格
brush.setStyle(Qt::Dense7Pattern);
//让画家使用画刷
painter.setBrush(brush);
painter.drawLine(QPoint(0,0),QPoint(100,100)); //画线
painter.drawEllipse(QPoint(100,100),50,50);//画圆(椭圆100 50)
painter.drawRect(QRect(20,20,50,50)); //画矩形
painter.drawText(QRect(10,200,150,50),"好好学习,天天向上");//画文字
}
Widget::~Widget()
{
delete ui;
}