修改QLabel的文本大小/颜色/背景颜色，使用QSS/QColor转换为QString的方法

QString foreground = TOOLBOX.qColor2qString(forecolor);
QString background = TOOLBOX.qColor2qString(backcolor);
//eg."QLabel{color:rgb(255,0,0);background-color:rgb(200,101,102);}"
QString qss = QString("QLabel{color:%1;background-color:%2;font:13pt}").arg(foreground).arg(background);
ui->label_systemstatus->setStyleSheet(qss);

QString CToolBox::qColor2qString(const QColor &color, const QString &type)
{
    if (type == "RGBA")
    {
        return QString("rgba(%1,%2,%3,%4)")
            .arg(color.red())
            .arg(color.green())
            .arg(color.blue())
            .arg(color.alpha());
    }
    else if (type == "RGB")
    {
        return QString("rgb(%1,%2,%3)")
            .arg(color.red())
            .arg(color.green())
            .arg(color.blue());
    }
    else if (type == "HEX")
    {
        return QString().sprintf("#%1%02X%02X%02X",
                                 color.red(),
                                 color.green(),
                                 color.blue())
            .arg(color.alpha() != 255 ? QString().sprintf("%02X", color.alpha()) : QString());
    }
    return color.name();
}