QPanter 绘画

Qpainter 绘图

1 绘图事件 void paintEvent(QPaintEvent *event)

2 声明一个画家对象 QPainter painter(this) this 指定绘图设备

3 画线圆矩形文字等

4 设置画笔 QPen 设置画笔宽度，风格

5 设置画刷 QBrush 设置画刷风格

QPainter qPainter(this);//实例化画家对象 this 执向的是绘画设备

    //画线

    qPainter.drawLine(10,10,100,100);

    QPen pen(QColor(255,222,0));

    qPainter.setPen(pen);

    pen.setWidth(3);

    QBrush qBrush(Qt::cyan);

    qPainter.setBrush(qBrush);

    qPainter.drawEllipse(QPoint(100,100),50,30);

    qPainter.drawRect(QRect(200,200,100,100));

    qPainter.drawText(QRect(100,200,100,100),"到店下班了      11");

QPainter 高级设置

1 抗锯齿效率低画的更精细 painter2.setRenderHint(QPainter::HighQualityAntialiasing);

2 对画家进行移动。painter2.translate(300,20);

3 保存画家状态。painter2.save();

4 还原画家状态 painter2.restore();

    //高级

    QPainter painter2(this);

    painter2.drawEllipse(200,20,100,100);

    painter2.translate(300,20);

    painter2.setRenderHint(QPainter::HighQualityAntialiasing);

    painter2.save();

    painter2.drawEllipse(200,20,100,100);

    painter2.restore();

    painter2.drawEllipse(200,20,100,100);

手动调用一下painter 用update

1 利用画家画图片 drawPixmap(posx,300,QPixmap(":/8by.png"));

widget.h

public:

   int posx;

protected:

    void paintEvent(QPaintEvent *event);

widget.cpp

\#include "widget.h"

#include "ui_widget.h"

#include<QPaintEvent>

#include<QPainter>

Widget::Widget(QWidget *parent)

    : QWidget(parent)

    , ui(new Ui::Widget)

{

    ui->setupUi(this);

        posx = 20;

        connect(ui->pushButton,&QPushButton::clicked,[=](){

            update();

            posx+=20;

        });

}

Widget::~Widget()

{

    delete ui;

}

void Widget::paintEvent(QPaintEvent *event)

{

    QPainter qPainter(this);//实例化画家对象 this 执向的是绘画设备

    //画线

    qPainter.drawLine(10,10,100,100);

    QPen pen(QColor(255,222,0));

    qPainter.setPen(pen);

    pen.setWidth(3);

    QBrush qBrush(Qt::cyan);

    qPainter.setBrush(qBrush);

    qPainter.drawEllipse(QPoint(100,100),50,30);

    qPainter.drawRect(QRect(200,200,100,100));

    qPainter.drawText(QRect(100,200,100,100),"到店下班了      11");

    //高级

    QPainter painter2(this);

    painter2.drawEllipse(200,20,100,100);

    painter2.translate(300,20);

    painter2.setRenderHint(QPainter::HighQualityAntialiasing);

    painter2.save();

    painter2.drawEllipse(200,20,100,100);

    painter2.restore();

    painter2.drawEllipse(200,20,100,100);

    ///////画图////////

    QPainter painter3(this);

    if(posx > this->width()){

        posx= 20;

    }

    painter3.drawPixmap(posx,300,QPixmap(":/8by.png"));

}

巴特西

QPanter 绘画

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