Qt 透明窗体设置

参考自http://blog.sina.com.cn/s/blog_a6fb6cc90101i19x.html

一，全透明

　　setWindowOpacity(0.5);

    取值范围为：0.0 - 1.0，默认值为1.0，全透明为0.0，不透明则为1.0。

二、主窗体透明（子窗体不透明）

1、主窗体采用背景色

setAttribute(Qt::WA_TranslucentBackground, true);

void paintEvent(QPaintEvent *event)

{

    QPainter painter(this);

    painter.fillRect(this->rect(), QColor(0, 0, 255, 80));  //QColor最后一个参数80代表背景的透明度

}

 

2、主窗体采用背景图片

setAttribute(Qt::WA_TranslucentBackground, true);

void QZXingWidget::paintEvent(QPaintEvent *event)

{

    QPixmap covert_pixmap(":/Images/background");

    QPixmap pixmap(covert_pixmap.width(), covert_pixmap.height());

    pixmap.fill(Qt::transparent); 

    QPainter painter(&pixmap);

    QPoint start_point(0, 0);

    QPoint end_point(0, pixmap.height());

    //QLinearGradient进行渐变色设置

    QLinearGradient linear_gradient(start_point, end_point);

    linear_gradient.setColorAt(0, QColor(255, 255, 255, 100));

    linear_gradient.setColorAt(0.5, QColor(255, 255, 255, 150));

    linear_gradient.setColorAt(1, QColor(255, 255, 255, 255));

    painter.fillRect(this->rect(), QBrush(linear_gradient));

    painter.setCompositionMode(QPainter::CompositionMode_SourceIn); 

    painter.drawPixmap(0, 0, covert_pixmap);

    painter.end();

 

    QPainter painter2(this);

    painter2.drawPixmap(0, 0, pixmap);

}