Qt Qpainter 画柱状图

 

void ScopeSetting::paintWidget()
{
    qDebug()<<"value ++"<<value;
    QPainter painter(ui->widget_3);
    QPainterPath path;
    int w = 25;
    int x = 60; 
    int y = 30;
    for(int i = 0; i < value; i++)
    {
        path.addRect(x, y, w, 150 - dBValue[i]);
        path.addRect(x, y, w, 150);
        //字体
        QFont font("宋体", 10);
        path.addText(x + 4, 150 - dBValue[i] + y - 2, font, QString::number(dBValue[i]));
        painter.drawPath(path);
        if(dBValue[i] > 120)
        {
            painter.fillRect(QRect(x, y + 150 - dBValue[i], w, dBValue[i]), QBrush(Qt::red));
        }
        else
        {
            painter.fillRect(QRect(x, y + 150 - dBValue[i], w, dBValue[i]), QBrush(QColor(107, 194, 53)));
        }
        x = x + 70;
    }
}

调用 update() 函数、会触发paintWidget() 函数