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Qt音视频开发26-监控画面各种图形绘制设计 [复制链接]

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离线liudianwu
 

图酷模式  只看楼主 倒序阅读 楼主  发表于: 2023-03-19


## 一、前言
视频监控系统做到后面,逐渐需要搭配人工智能算法,将算法计算后的信息以OSD标签以及方框各种图形的信息显示到视频中,这种当然和OSD一样也是有两种方式,一种是源头就贴好了,一种是将结果发给软件这边解析绘制,于是才需要这种通用的图形绘制需求,有了之前OSD标签信息的经验,这个在最初设计的时候就考虑了很多可能的要素,比如图形的边框大小、边框颜色、背景颜色,区域为了兼容更多的内容,除了矩形,还支持QPainterPath路径集合,多边形区域QList<QPoint>点坐标集合,尤其是QPainterPath路径集合涵盖了所有可能的情况,只是对程序员使用者要求高很多,需要自己填充这个路径集合然后传入进来。

一般都是矩形区域居多,比如人脸框,人体区域、物体区域等,都是一个矩形区域,图形信息和OSD标签信息一样,都可以选择三种绘制方式,一种是绘制到覆盖窗体中,一种是绘制到图片中,一种是源头数据绘制好,如果源头支持的尽量源头就绘制好,比如ffmpeg的滤镜就专干这事的,而且干的非常漂亮,亲测几千个文字使用和几千个矩形框同时绘制在源头数据中,效果非常好,性能还是非常高的,就是数量越多占用CPU越高。

```cpp
//图形信息(人脸框和多边形区域等)
struct GraphInfo {
    QString name;               //名字唯一标识符(方便删除或更新)
    int borderWidth;            //边框大小
    QColor borderColor;         //边框颜色
    QColor bgColor;             //背景颜色

    QRect rect;                 //矩形区域
    QPainterPath path;          //路径集合
    QList<QPoint> points;       //点坐标集合

    GraphInfo() {
        name = "graph";
        borderWidth = 2;
        borderColor = "#FF0000";
        bgColor = Qt::transparent;
    }
};
```

## 二、效果图



## 三、体验地址
1. 国内站点:[https://gitee.com/feiyangqingyun](https://gitee.com/feiyangqingyun)
2. 国际站点:[https://github.com/feiyangqingyun](https://github.com/feiyangqingyun)
3. 个人作品:[https://blog.csdn.net/feiyangqingyun/article/details/97565652](https://blog.csdn.net/feiyangqingyun/article/details/97565652)
4. 体验地址:[https://pan.baidu.com/s/1d7TH_GEYl5nOecuNlWJJ7g](https://pan.baidu.com/s/1d7TH_GEYl5nOecuNlWJJ7g) 提取码:01jf 文件名:bin_video_demo/bin_linux_video。

## 四、相关代码
```cpp
void WidgetHelper::drawRect(QPainter *painter, const QRect &rect, int borderWidth, QColor borderColor, bool angle)
{
    painter->setPen(QPen(borderColor, borderWidth));
    //背景颜色
    borderColor.setAlpha(50);
    //painter->setBrush(QBrush(borderColor));

    int x = rect.x();
    int y = rect.y();
    int width = rect.width();
    int height = rect.height();

    if (!angle) {
        painter->drawRect(x, y, width, height);
    } else {
        //绘制四个角
        int offset = 10;
        painter->drawLine(x, y, x + offset, y);
        painter->drawLine(x, y, x, y + offset);
        painter->drawLine(x + width - offset, y, x + width, y);
        painter->drawLine(x + width, y, x + width, y + offset);
        painter->drawLine(x, y + height - offset, x, y + height);
        painter->drawLine(x, y + height, x + offset, y + height);
        painter->drawLine(x + width - offset, y + height, x + width, y + height);
        painter->drawLine(x + width, y + height - offset, x + width, y + height);
    }
}

void WidgetHelper::drawPoints(QPainter *painter, const QList<QPoint> &pts, int borderWidth, QColor borderColor)
{
    //至少要两个点
    if (pts.count() < 2) {
        return;
    }

    painter->setPen(QPen(borderColor, borderWidth));
    //背景颜色
    borderColor.setAlpha(50);
    //painter->setBrush(QBrush(borderColor));

    //绘制多边形
    QPainterPath path;
    //先移动到起始点
    path.moveTo(pts.first());
    //逐个连接线条
    int count = pts.count();
    for (int i = 1; i < count; ++i) {
        path.lineTo(pts.at(i));
    }

    //闭合图形
    path.closeSubpath();
    painter->drawPath(path);
}

void WidgetHelper::drawPath(QPainter *painter, QPainterPath path, int borderWidth, QColor borderColor)
{
    painter->setPen(QPen(borderColor, borderWidth));
    painter->drawPath(path);
}

void AbstractVideoWidget::drawInfo(QPainter *painter)
{
    //只有音频和句柄模式不用绘制OSD
    if (videoWidth == 0 || onlyAudio || widgetPara.videoMode == VideoMode_Hwnd) {
        return;
    }

    //标签位置尽量偏移多一点避免遮挡
    QRect rect = image.isNull() ? coverWidget->rect() : image.rect();
    int borderWidth = widgetPara.borderWidth + 5;
    rect = QRect(rect.x() + borderWidth, rect.y() + borderWidth, rect.width() - (borderWidth * 2), rect.height() - (borderWidth * 2));

    //将标签信息绘制到遮罩层
    if (widgetPara.osdDrawMode == DrawMode_Cover) {
        foreach (OsdInfo osd, listOsd) {
            if (osd.visible) {
                painter->save();
                WidgetHelper::drawOsd(painter, osd, rect);
                painter->restore();
            }
        }
    }

    //将图形信息绘制到遮罩层
    if (widgetPara.graphDrawMode == DrawMode_Cover) {
        foreach (GraphInfo graph, listGraph) {
            painter->save();
            if (!graph.rect.isEmpty()) {
                WidgetHelper::drawRect(painter, graph.rect, graph.borderWidth, graph.borderColor);
            }
            if (!graph.path.isEmpty()) {
                WidgetHelper::drawPath(painter, graph.path, graph.borderWidth, graph.borderColor);
            }
            if (graph.points.count() > 0) {
                WidgetHelper::drawPoints(painter, graph.points, graph.borderWidth, graph.borderColor);
            }
            painter->restore();
        }
    }
}

void AbstractVideoWidget::drawImage(QPainter *painter)
{
    if (image.isNull()) {
        return;
    }

    //标签位置尽量偏移多一点避免遮挡
    QRect rect = image.isNull() ? coverWidget->rect() : image.rect();
    int borderWidth = widgetPara.borderWidth + 5;
    rect = QRect(rect.x() + borderWidth, rect.y() + borderWidth, rect.width() - (borderWidth * 2), rect.height() - (borderWidth * 2));

    //将标签信息绘制到图片上
    if (widgetPara.osdDrawMode == DrawMode_Image) {
        foreach (OsdInfo osd, listOsd) {
            if (osd.visible) {
                QPainter painter;
                painter.begin(&image);
                //painter.setRenderHints(QPainter::Antialiasing);
                WidgetHelper::drawOsd(&painter, osd, rect);
                painter.end();
            }
        }
    }

    //将图形信息绘制到图片上
    if (widgetPara.graphDrawMode == DrawMode_Image) {
        foreach (GraphInfo graph, listGraph) {
            QPainter painter;
            painter.begin(&image);
            //painter.setRenderHints(QPainter::Antialiasing);
            if (!graph.rect.isEmpty()) {
                WidgetHelper::drawRect(&painter, graph.rect, graph.borderWidth, graph.borderColor);
            }
            if (!graph.path.isEmpty()) {
                WidgetHelper::drawPath(&painter, graph.path, graph.borderWidth, graph.borderColor);
            }
            if (graph.points.count() > 0) {
                WidgetHelper::drawPoints(&painter, graph.points, graph.borderWidth, graph.borderColor);
            }
            painter.end();
        }
    }

    //绘制图片
    painter->save();
    painter->drawImage(imageRect, image);
    painter->restore();
}
```

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