Qt音视频开发44-实时人脸框

bool FFmpegWidget::eventFilter(QObject *watched, QEvent *event)
{
    if (watched == osdWidget && event->type() == QEvent::Paint) {
        if (drawImage) {
            QPainter painter;
            painter.begin(osdWidget);
            painter.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);

            //绘制边框
            drawBorder(&painter);
            if (thread->getIsInit()) {
                //绘制背景图片
                drawImg(&painter, image);
                //绘制人脸框
                drawFace(&painter);
                //绘制标签
                drawOSD(&painter, osd1Visible, osd1FontSize, osd1Text, osd1Color, osd1Image, osd1Format, osd1Position);
                drawOSD(&painter, osd2Visible, osd2FontSize, osd2Text, osd2Color, osd2Image, osd2Format, osd2Position);
            } else {
                //绘制背景
                if (!isDrag) {
                    drawBg(&painter);
                }
            }

            painter.end();
        }
    }

    return QWidget::eventFilter(watched, event);
}

void FFmpegWidget::drawBorder(QPainter *painter)
{
    if (borderWidth == 0) {
        return;
    }

    painter->save();
    QPen pen;
    pen.setWidth(borderWidth);
    pen.setColor(hasFocus() ? focusColor : borderColor);
    painter->setPen(pen);
    painter->drawRect(rect());
    painter->restore();
}

void FFmpegWidget::drawBg(QPainter *painter)
{
    painter->save();

    //背景图片为空则绘制文字,否则绘制背景图片
    if (bgImage.isNull()) {
        painter->setFont(this->font());
        painter->setPen(palette().foreground().color());
        painter->drawText(rect(), Qt::AlignCenter, bgText);
    } else {
        //居中绘制
        int x = rect().center().x() - bgImage.width() / 2;
        int y = rect().center().y() - bgImage.height() / 2;
        QPoint point(x, y);
        painter->drawImage(point, bgImage);
    }

    painter->restore();
}

void FFmpegWidget::drawImg(QPainter *painter, QImage img)
{
    if (img.isNull()) {
        return;
    }

    painter->save();

    int offset = borderWidth * 1 + 0;
    img = img.scaled(width() - offset, height() - offset, Qt::KeepAspectRatio, Qt::SmoothTransformation);

    if (fillImage) {
        QRect rect(offset / 2, offset / 2, width() - offset, height() - offset);
        painter->drawImage(rect, img);
    } else {
        //按照比例自动居中绘制
        int x = rect().center().x() - img.width() / 2;
        int y = rect().center().y() - img.height() / 2;
        QPoint point(x, y);
        painter->drawImage(point, img);
    }

    painter->restore();
}

void FFmpegWidget::drawFace(QPainter *painter)
{
    if (faceRects.count() == 0) {
        return;
    }

    painter->save();

    //人脸边框的颜色
    QPen pen;
    pen.setWidth(faceBorder);
    pen.setColor(faceColor);
    painter->setPen(pen);

    //逐个取出人脸框区域进行绘制
    foreach (QRect rect, faceRects) {
        painter->drawRect(rect);
    }

    painter->restore();
}

void FFmpegWidget::drawOSD(QPainter *painter,
                           bool osdVisible,
                           int osdFontSize,
                           const QString &osdText,
                           const QColor &osdColor,
                           const QImage &osdImage,
                           const FFmpegWidget::OSDFormat &osdFormat,
                           const FFmpegWidget::OSDPosition &osdPosition)
{
    if (!osdVisible) {
        return;
    }

    painter->save();

    //标签位置尽量偏移多一点避免遮挡
    QRect osdRect(rect().x() + (borderWidth * 2), rect().y() + (borderWidth * 2), width() - (borderWidth * 5), height() - (borderWidth * 5));
    int flag = Qt::AlignLeft | Qt::AlignTop;
    QPoint point = QPoint(osdRect.x(), osdRect.y());

    if (osdPosition == OSDPosition_Left_Top) {
        flag = Qt::AlignLeft | Qt::AlignTop;
        point = QPoint(osdRect.x(), osdRect.y());
    } else if (osdPosition == OSDPosition_Left_Bottom) {
        flag = Qt::AlignLeft | Qt::AlignBottom;
        point = QPoint(osdRect.x(), osdRect.height() - osdImage.height());
    } else if (osdPosition == OSDPosition_Right_Top) {
        flag = Qt::AlignRight | Qt::AlignTop;
        point = QPoint(osdRect.width() - osdImage.width(), osdRect.y());
    } else if (osdPosition == OSDPosition_Right_Bottom) {
        flag = Qt::AlignRight | Qt::AlignBottom;
        point = QPoint(osdRect.width() - osdImage.width(), osdRect.height() - osdImage.height());
    }

    if (osdFormat == OSDFormat_Image) {
        painter->drawImage(point, osdImage);
    } else {
        QDateTime now = QDateTime::currentDateTime();
        QString text = osdText;
        if (osdFormat == OSDFormat_Date) {
            text = now.toString("yyyy-MM-dd");
        } else if (osdFormat == OSDFormat_Time) {
            text = now.toString("HH:mm:ss");
        } else if (osdFormat == OSDFormat_DateTime) {
            text = now.toString("yyyy-MM-dd HH:mm:ss");
        }

        //设置颜色及字号
        QFont font;
        font.setPixelSize(osdFontSize);
        painter->setPen(osdColor);
        painter->setFont(font);

        painter->drawText(osdRect, flag, text);
    }

    painter->restore();
}