qt 卡拉OK 歌词效果

// 思路：一、先绘制全部歌词 二、设置裁剪区域 三、绘制已经唱的歌词

void Widget::paintEvent(QPaintEvent *event)

{

    QLineF line(10.0, 80.0, 90.0, 20.0);

    QPainter painter(this);

    QString m_sText = "测试文本 test";

    // 设置抗锯齿

    painter.setRenderHint(QPainter::Antialiasing);

    // 设置字体

    QFont font = painter.font();

    font.setPixelSize(240);

    painter.setFont(font);

    // 确定位置

    QFontMetrics metrics = painter.fontMetrics();

    int width = metrics.width(m_sText);

    int height = metrics.height();

    int xPt = (this->rect().width() - width) / 2;

    int yPt = (this->rect().height() - height) / 2 + height;

    // 设置绘制路径

    QPainterPath path;

    path.addText(xPt, yPt, font, m_sText);//文字

//    path.addRect(QRect(xPt, yPt - height, width, height));

    // 一、绘制全部歌词

    // 1、绘制轮廓

    QPen pen;

    pen.setWidth(8);//轮廓粗细8

    pen.setColor(QColor(0, 0, 0));

    painter.strokePath(path, pen);

    // 2、绘制中间文字

//    pen.setWidth(1);

    pen.setColor(QColor(255, 255, 255));

    painter.setPen(pen);

    painter.drawText(QPoint(xPt, yPt), m_sText);//The y-position is used as the baseline of the font.

    // 二、绘制演唱进度

    //1、设置裁剪区域，超出区域就不画

    painter.setClipRect(QRect(xPt, yPt-height+metrics.descent(), width/2, height));

    //2、绘制轮廓

    pen.setColor(QColor(255, 255, 255));

    painter.strokePath(path, pen);

    //3、绘制演唱进度文字

    pen.setColor(QColor(0, 0, 255));

    painter.setPen(pen);

    painter.drawText(QRect(xPt, yPt-height+metrics.descent(), width/2, height),  Qt::AlignLeft, m_sText);

//    painter.drawRect(QRect(xPt, yPt-height+metrics.descent(), width/2, height));

}