Qt：QtPainter设置画刷

墨蓝 2022-10-24 11:45 10阅读 0赞

/\*  
\* 1、新建QT GUI， 基类选择QWidget，取消“创建界面”  
\* 2、添加资源文件qtlogn：在项目之下添加一个“resources”文件，里面存放"qtblog.png"，然后  
\* 文件-->新建文件/项目--->Qt---> Qt Resource File  
\* 3、在widget.h中添加\#include <QPainter>和重写绘画事件定义：  
\* protected:  
void paintEvent(QPaintEvent \*event);  
\* 4、在widget.cpp中添加重绘事件

\*/

1、QRadialGradient

void Widget::paintEvent(QPaintEvent *event)
    {
        QPainter painter;
        painter.begin(this);
    
        QRadialGradient gradient(50, 50, 50, 50, 50);
        gradient.setColorAt(0, QColor::fromRgbF(0, 1, 0, 1));
        gradient.setColorAt(1, QColor::fromRgbF(0, 0, 0, 0));
        QBrush brush(gradient);
    
        painter.setBrush(brush);
        painter.drawRect(0, 0, 100, 100);
    
        painter.end();
    }

![28d292d63f92ef5b677b4d52b9c921e3338.jpg][]

2、设置画刷为pixmap文件

void Widget::paintEvent(QPaintEvent *event)
    {
        QPainter painter;
        painter.begin(this);
    
        QPixmap pixmap("F:\\MyCode\\brush\\resources\\qtblog.png");
        int w = pixmap.width();
        int h = pixmap.height();
        pixmap.scaled(w, h, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
    
        QBrush brush(pixmap);   //设置画刷为pixmap文件：也就是用pixmap图形填充矩形
        painter.setBrush(brush);
        painter.drawRect(0, 0, w, h);
        painter.end();
    }

![e980d0b68014109335683d54162e1539ab0.jpg][]

3、设置画刷的填充颜色

void Widget::paintEvent(QPaintEvent *event)
    {
        QPainter painter;
        painter.begin(this);
        painter.setPen(Qt::blue);
        painter.setBrush(QBrush(Qt::green, Qt::Dense3Pattern));
        painter.drawEllipse(10, 10, 100,100);
        painter.setBrush(Qt::NoBrush);
        painter.drawEllipse(80, 10, 100, 100);
        painter.end();
    }

![a13d0b144765b9f1306cf39e7bd11fe9049.jpg][]

资源文件

![qtblog.png][]

[28d292d63f92ef5b677b4d52b9c921e3338.jpg]: /images/20221024/2d17aeabf09a45369f6ee34238d2f81d.png
[e980d0b68014109335683d54162e1539ab0.jpg]: /images/20221024/2eab036237c1424e848908d124d7cdcf.png
[a13d0b144765b9f1306cf39e7bd11fe9049.jpg]: /images/20221024/10327e8a03424ca4acce0106ff2f1ca8.png
[qtblog.png]: /images/20221024/78181edf0fe74b3b82a368d7d32521b6.png