四、线段、矩形、圆、椭圆、自定义多边形、边缘轮廓和文本绘制（OpenCvSharp）

功能实现：
对指定图片上进行绘制线段、矩形、圆、椭圆、自定义多边形、边缘轮廓以及自定义文本

一、布局

用到了一个pictureBox和八个button

二、引入命名空间

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using OpenCvSharp;
// using Point = OpenCvSharp.Point;
using OpenCvSharp.Extensions;

要有这三个哈，没有就去浏览里面搜索下载安装就行

三、功能实现

1，OpenPicture，选择图片

定义全局变量picture用于存放读取的图片的位置

OpenFileDialog file = new OpenFileDialog();
new一个OpenFileDialog 类对象file，用于打开选择图片
OpenFileDialog 类官网API

if (file.FileName != string.Empty)
此时file.FileName就是图片的路径，是一个字符串数据

pictureBox1.Load(file.FileName);
pictureBox1就是布局里面的PictureBox控件名称
参数是图片的路径，这里传入用户选择的图片路径file.FileName
此时就可以将用户选择的照片显示在PictureBox控件上

private string picture = ""; // 全局变量存放读取图片的路径

private void button1_Click(object sender, EventArgs e)
{
    OpenFileDialog file = new OpenFileDialog();
    file.InitialDirectory = ".";
    file.Filter = "所有文件(*.*)|*.*";
    file.ShowDialog();
    if (file.FileName != string.Empty)
    {
        try
        {
            picture = file.FileName;
            this.pictureBox1.Load(file.FileName);
            Console.WriteLine("picture path is: " + picture);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }  
}

运行效果展示：
这里为了更加方便展示功能，制作了一个纯黑的图片（1000×400）

2，Line，绘制线段

Mat src_line = new Mat();
src_line = Cv2.ImRead(this.picture, ImreadModes.Color);
创建一个Mat对象src_line ，用于存放读取的图片

OpenCvSharp.Point pt1, pt2;
pt1.X = 10; pt1.Y = 20; pt2.X = 50; pt2.Y = 60;
设置线段的起点的终点坐标

Scalar scalar = new Scalar(0, 0, 255); // BGR
线段颜色，红色

Cv2.Line(src_line, pt1, pt2, scalar, 2, LineTypes.AntiAlias, 0);
参数一：src_line，要绘制的图片
参数二：pt1，起点
参数三：pt2，终点
参数四：scalar，线段颜色红色
参数五：2，线段粗细，越大越粗
参数六：LineTypes.AntiAlias，线段的类型
参数七：0，shift为0，表示缩放程度，无放缩
Cv2.Line Method (InputOutputArray, Int32, Int32, Int32, Int32, Scalar, Int32, LineTypes, Int32)

Bitmap bitmap_line = src_line.ToBitmap();
因为OpenCV读取的是Mat类型的图片，而pictureBox控件只能显示Bitmap和Image类型的数据，故需要将Mat转换为Bitmap
Mat、Bitmap和Image数据格式之间的相互转换可参考博文：三、Mat、Bitmap和Image数据类型之间的转换（OpenCvSharp）

pictureBox1.Image = bitmap_line;
将绘制好的Bitmap图片在pictureBox1控件上展示

private void button2_Click(object sender, EventArgs e)
{
    Mat src_line = new Mat();
    src_line = Cv2.ImRead(this.picture, ImreadModes.Color);

    // 设置线段的起点和终点的位置
    OpenCvSharp.Point pt1, pt2;
    pt1.X = 10;
    pt1.Y = 20;
    pt2.X = 50;
    pt2.Y = 60;
    // OpenCvSharp.Point pt1 = new OpenCvSharp.Point(100, 400);
    // OpenCvSharp.Point pt2 = new OpenCvSharp.Point(200, 800);

    Scalar scalar = new Scalar(0, 0, 255); // BGR
    Cv2.Line(src_line, pt1, pt2, scalar, 2, LineTypes.AntiAlias, 0);
    Bitmap bitmap_line = src_line.ToBitmap();
    pictureBox1.Image = bitmap_line;
    // Cv2.ImShow("src",src);
    // Cv2.WaitKey(0);
}

运行效果展示：
横x轴，竖y轴

3，Rectangle，绘制矩形框

Mat src_rectangle = new Mat();
src_rectangle = Cv2.ImRead(this.picture, ImreadModes.Color);
创建一个Mat对象src_rectangle ，用于存放读取的图片

OpenCvSharp.Point pt1 = new OpenCvSharp.Point(10, 20);
OpenCvSharp.Point pt2 = new OpenCvSharp.Point(20, 50);
设置左上角和右下角的坐标位置

Scalar scalar = new Scalar(0, 255, 0);
设置线段颜色BGR，这里是绿色

Cv2.Rectangle(src_rectangle, pt1, pt2, scalar, 2, LineTypes.Link4, 0);
参数一：src_rectangle，要绘制的图片
参数二：pt1，矩形左上角坐标位置
参数三：pt2，矩形右下角坐标位置
参数四：scalar，线段颜色绿色
参数五：2，线段粗细，越大越粗
参数六：LineTypes.Link4，线段的类型
参数七：0，shift为0，表示缩放程度，无放缩
Cv2.Rectangle Method (Mat, Rect, Scalar, Int32, LineTypes, Int32)

Bitmap bitmap_rect = src_rectangle.ToBitmap();
因为OpenCV读取的是Mat类型的图片，而pictureBox控件只能显示Bitmap和Image类型的数据，故需要将Mat转换为Bitmap

pictureBox1.Image = bitmap_rect;
将绘制好的Bitmap图片在pictureBox1控件上展示

private void button3_Click(object sender, EventArgs e)
{
    Mat src_rectangle = new Mat();
    src_rectangle = Cv2.ImRead(this.picture, ImreadModes.Color);

    // 设置矩形的左上和右下点的位置
    OpenCvSharp.Point pt1 = new OpenCvSharp.Point(10, 20);
    OpenCvSharp.Point pt2 = new OpenCvSharp.Point(20, 50);
    Scalar scalar = new Scalar(0, 255, 0); // BGR
    Cv2.Rectangle(src_rectangle, pt1, pt2, scalar, 2, LineTypes.Link4, 0);

    Bitmap bitmap_rect = src_rectangle.ToBitmap();
    pictureBox1.Image = bitmap_rect;
}

运行效果展示：

4，Circle，绘制圆形

Mat src_circle = new Mat();
src_circle = Cv2.ImRead(this.picture, ImreadModes.Color);
创建一个Mat对象src_circle ，用于存放读取的图片

OpenCvSharp.Point pt1 = new OpenCvSharp.Point(100, 60);
设置圆心坐标位置

Cv2.Circle(src_circle, pt1, 50, new Scalar(255, 0, 0), 2, LineTypes.Link8, 0);
参数一：src_circle，要绘制的图片
参数二：pt1，圆心坐标位置
参数三：50，圆的半径
参数四：new Scalar(255, 0, 0)，BGR，线段颜色蓝色
参数五：2，线段粗细，越大越粗
参数六：LineTypes.Link8，线段的类型
参数七：0，shift为0，表示缩放程度，无放缩
Cv2.Circle Method (InputOutputArray, Point, Int32, Scalar, Int32, LineTypes, Int32)

Bitmap bitmap_circle = src_circle.ToBitmap();
因为OpenCV读取的是Mat类型的图片，而pictureBox控件只能显示Bitmap和Image类型的数据，故需要将Mat转换为Bitmap

pictureBox1.Image = bitmap_circle;
将绘制好的Bitmap图片在pictureBox1控件上展示

private void button4_Click(object sender, EventArgs e)
{
    Mat src_circle = new Mat();
    src_circle = Cv2.ImRead(this.picture, ImreadModes.Color);

    // 设置圆心位置
    OpenCvSharp.Point pt1 = new OpenCvSharp.Point(100, 60);
    Scalar scalar = new Scalar(255, 0, 0); // BGR
    Cv2.Circle(src_circle, pt1, 50, scalar, 2, LineTypes.Link8, 0);

    Bitmap bitmap_circle = src_circle.ToBitmap();
    pictureBox1.Image = bitmap_circle;
}

运行效果展示：

5，Ellipse，绘制椭圆

Mat src_ellipse = new Mat();
src_ellipse = Cv2.ImRead(this.picture, ImreadModes.Color);
创建一个Mat对象src_circle ，用于存放读取的图片

OpenCvSharp.Point pt;
pt.X = 60; pt.Y = 60;
设置椭圆中心位置

OpenCvSharp.Size size;
size.Width = 50; size.Height = 10;
设置长半轴(size.Width，黄色)和短半轴(size.Height，蓝色)

Scalar scalar = new Scalar(255, 0, 255);
设置绘制线段的颜色BGR，蓝+红=紫

Cv2.Ellipse(src_ellipse, pt, size, 270, 0, 270, scalar, 2, LineTypes.AntiAlias, 0);
参数一：src_ellipse，要绘制的图片
参数二：pt，椭圆圆心坐标位置
参数三：size，椭圆的长半轴和短半轴
参数四：270，椭圆的角度
参数五：0，开始的角度，竖直为0度，也就是12点钟位置
参数六：270，结束的角度，顺时针转270度
参数七：scalar，BGR，线段颜色紫色
参数八：2，线段粗细，越大越粗
参数九：LineTypes.AntiAlias，线段的类型
参数十：0，shift为0，表示缩放程度，无放缩
Cv2.Ellipse Method (InputOutputArray, Point, Size, Double, Double, Double, Scalar, Int32, LineTypes, Int32)

Bitmap bitmap_ellipse = src_ellipse.ToBitmap();
因为OpenCV读取的是Mat类型的图片，而pictureBox控件只能显示Bitmap和Image类型的数据，故需要将Mat转换为Bitmap

pictureBox1.Image = bitmap_ellipse;
将绘制好的Bitmap图片在pictureBox1控件上展示

private void button5_Click(object sender, EventArgs e)
{
    Mat src_ellipse = new Mat();
    src_ellipse = Cv2.ImRead(this.picture, ImreadModes.Color);

    // 设置椭圆中心位置
    OpenCvSharp.Point pt;
    pt.X = 60;
    pt.Y = 60;
    
    // 设置长半轴和短半轴
    OpenCvSharp.Size size;
    size.Width = 50;
    size.Height = 10;
    
    Scalar scalar = new Scalar(255, 0, 255); // BGR

    Cv2.Ellipse(src_ellipse, pt, size, 270, 0, 270, scalar, 2, LineTypes.AntiAlias, 0);
    Bitmap bitmap_ellipse = src_ellipse.ToBitmap();
    pictureBox1.Image = bitmap_ellipse;
}

运行效果展示：

6，Polylines，绘制多边形

Mat src_poly = new Mat();
src_poly = Cv2.ImRead(this.picture, ImreadModes.Color);
创建一个Mat对象src_poly ，用于存放读取的图片

// pt1是一个三角形，一定要密闭哈，回归原来的起始点坐标
// pt1是一个矩形

List<OpenCvSharp.Point> pts1 = new List<OpenCvSharp.Point>
{
    new OpenCvSharp.Point(30,10),
    new OpenCvSharp.Point(50,50),
    new OpenCvSharp.Point(10,50),
    new OpenCvSharp.Point(30,10)
};

List<OpenCvSharp.Point> pts2 = new List<OpenCvSharp.Point>
{
    new OpenCvSharp.Point(70,10),
    new OpenCvSharp.Point(100,10),
    new OpenCvSharp.Point(100,50),
    new OpenCvSharp.Point(70,50),
    new OpenCvSharp.Point(70,10)
};

List<List<OpenCvSharp.Point>> pts = new List<List<OpenCvSharp.Point>>() { pts1, pts2 };
pts是俩多边形坐标点的位置，一个是pts1三角形，另一个是pts2矩形

Cv2.Polylines(src_poly, pts, true, new Scalar(0, 255, 255), 2, LineTypes.AntiAlias, 0);
参数一：src_poly，要绘制的图片
参数二：pts，待绘制多边形的各个点的位置坐标
参数三：true，是否闭合，因为这边绘制多边形的时候回到最初的位置了，是闭合的区域
参数四：new Scalar(0, 255, 255)，BGR，线段颜色黄色
参数五：2，线段粗细，越大越粗
参数六：LineTypes.AntiAlias，线段的类型
参数七：0，shift为0，表示缩放程度，无放缩
Cv2.Polylines Method (InputOutputArray, InputArray, Boolean, Scalar, Int32, LineTypes, Int32)

Bitmap bitmap_poly = src_poly.ToBitmap();
因为OpenCV读取的是Mat类型的图片，而pictureBox控件只能显示Bitmap和Image类型的数据，故需要将Mat转换为Bitmap

pictureBox1.Image = bitmap_poly;
将绘制好的Bitmap图片在pictureBox1控件上展示

private void button6_Click(object sender, EventArgs e)
{
    Mat src_poly = new Mat();
    src_poly = Cv2.ImRead(this.picture, ImreadModes.Color);

    List<OpenCvSharp.Point> pts1 = new List<OpenCvSharp.Point>
    {
        new OpenCvSharp.Point(30,10),
        new OpenCvSharp.Point(50,50),
        new OpenCvSharp.Point(10,50),
        new OpenCvSharp.Point(30,10)
    };
    List<OpenCvSharp.Point> pts2 = new List<OpenCvSharp.Point>
    {
        new OpenCvSharp.Point(70,10),
        new OpenCvSharp.Point(100,10),
        new OpenCvSharp.Point(100,50),
        new OpenCvSharp.Point(70,50),
        new OpenCvSharp.Point(70,10)
    };

    List<List<OpenCvSharp.Point>> pts = new List<List<OpenCvSharp.Point>>() { pts1, pts2 };

    Cv2.Polylines(src_poly, pts, true, new Scalar(0, 255, 255), 2, LineTypes.AntiAlias, 0);
    Bitmap bitmap_poly = src_poly.ToBitmap();
    pictureBox1.Image = bitmap_poly;
}

运行效果展示：

7，DrawContours，绘制轮廓

Mat src_contour = new Mat();
src_contour = Cv2.ImRead(this.picture, ImreadModes.Color);
创建一个Mat对象src_contour，用于存放读取的图片

// 五边形
List<OpenCvSharp.Point> pts1 = new List<OpenCvSharp.Point>
{
    new OpenCvSharp.Point(40,40),
    new OpenCvSharp.Point(40,50),
    new OpenCvSharp.Point(50,50),
    new OpenCvSharp.Point(50,40),
    new OpenCvSharp.Point(45,20),
    new OpenCvSharp.Point(40,40)
};

List<List<OpenCvSharp.Point>> pts = new List<List<OpenCvSharp.Point>>() { pts1 };
pts是一个五边形pts1

Cv2.DrawContours(src_contour, pts, -1, new Scalar(0, 255, 0), 1, LineTypes.AntiAlias);
参数一：src_contour，要绘制的图片
参数二：pts，待绘制轮廓的多边形点的坐标位置
参数三：-1，绘制哪个轮廓，-1表示所有的多边形轮廓都绘制
参数四：new Scalar(0, 255, 0)，BGR，线段颜色绿色
参数五：-1，线段粗细，越大越粗，-1表示填充该多边形
参数六：LineTypes.AntiAlias，线段的类型
Cv2.DrawContours Method (InputOutputArray, IEnumerable, Int32, Scalar, Int32, LineTypes, Mat, Int32, Nullable)

Bitmap bitmap_contour = src_contour.ToBitmap();
因为OpenCV读取的是Mat类型的图片，而pictureBox控件只能显示Bitmap和Image类型的数据，故需要将Mat转换为Bitmap

pictureBox1.Image = bitmap_contour;
将绘制好的Bitmap图片在pictureBox1控件上展示

private void button7_Click(object sender, EventArgs e)
{
    Mat src_contour = new Mat();
    src_contour = Cv2.ImRead(this.picture, ImreadModes.Color);

    List<OpenCvSharp.Point> pts1 = new List<OpenCvSharp.Point>
    {
        new OpenCvSharp.Point(40,40),
        new OpenCvSharp.Point(40,50),
        new OpenCvSharp.Point(50,50),
        new OpenCvSharp.Point(50,40),
        new OpenCvSharp.Point(45,20),
        new OpenCvSharp.Point(40,40)
    };

    List<List<OpenCvSharp.Point>> pts = new List<List<OpenCvSharp.Point>>() { pts1 };

    Cv2.DrawContours(src_contour, pts, -1, new Scalar(0, 255, 0), -1, LineTypes.AntiAlias);
    Bitmap bitmap_contour = src_contour.ToBitmap();
    pictureBox1.Image = bitmap_contour;
}

运行效果展示：

8，PutText，绘制文字

Mat src_text = new Mat();
src_text = Cv2.ImRead(this.picture, ImreadModes.Color);
创建一个Mat对象src_text ，用于存放读取的图片

OpenCvSharp.Point pt = new OpenCvSharp.Point(200, 200);
设置文字的起始位置，左上角坐标

Cv2.PutText(src_text, "beyondyanyu", pt, HersheyFonts.Italic, 3, new Scalar(0, 255, 0), 1, LineTypes.Link8, false);
参数一：src_text，要绘制的图片
参数二：“beyondyanyu”，待绘制文本内容
参数三：pt，文字左上角坐标位置
参数四：HersheyFonts.Italic，字体类型
参数五：3，字体范围
参数六：new Scalar(0, 255, 0)，BGR，线段颜色绿色
参数七：1，线段粗细，越大越粗
Cv2.PutText Method

Bitmap bitmap_text = src_text.ToBitmap();
因为OpenCV读取的是Mat类型的图片，而pictureBox控件只能显示Bitmap和Image类型的数据，故需要将Mat转换为Bitmap

pictureBox1.Image = bitmap_text;
将绘制好的Bitmap图片在pictureBox1控件上展示

private void button8_Click(object sender, EventArgs e)
{
    Mat src_text = new Mat();
    src_text = Cv2.ImRead(this.picture, ImreadModes.Color);
    
    OpenCvSharp.Point pt = new OpenCvSharp.Point(200, 200);
    
    Cv2.PutText(src_text,"beyondyanyu",pt,HersheyFonts.Italic,3, new Scalar(0, 255, 0),1,LineTypes.Link8,false);
    
    Bitmap bitmap_text = src_text.ToBitmap();
    pictureBox1.Image = bitmap_text;
}

运行效果展示：

四、完整代码

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using OpenCvSharp;
// using Point = OpenCvSharp.Point;
using OpenCvSharp.Extensions;

namespace Study_Point
{
    public partial class Form1 : Form
    {
        private string picture = ""; // 全局变量存放读取图片的路径
        public Form1()
        {
            InitializeComponent();
        }

        /// <summary>
        /// 选择图片
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog file = new OpenFileDialog();
            file.InitialDirectory = ".";
            file.Filter = "所有文件(*.*)|*.*";
            file.ShowDialog();
            if (file.FileName != string.Empty)
            {
                try
                {
                    picture = file.FileName;
                    this.pictureBox1.Load(file.FileName);
                    Console.WriteLine("picture path is: " + picture);
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }  
        }


        /// <summary>
        /// 画线段
        /// 参数一：src_line，要绘制的图片
        /// 参数二：pt1，起点
        /// 参数三：pt2，终点
        /// 参数四：scalar，线段颜色
        /// 参数五：2，线段粗细，越大越粗
        /// 参数六：LineTypes.AntiAlias，线段的类型
        /// 参数七：0，shift为0
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            Mat src_line = new Mat();
            src_line = Cv2.ImRead(this.picture, ImreadModes.Color);

            // 设置线段的起点和终点的位置
            OpenCvSharp.Point pt1, pt2;
            pt1.X = 10;
            pt1.Y = 20;
            pt2.X = 50;
            pt2.Y = 60;
            // OpenCvSharp.Point pt1 = new OpenCvSharp.Point(100, 400);
            // OpenCvSharp.Point pt2 = new OpenCvSharp.Point(200, 800);

            Scalar scalar = new Scalar(0, 0, 255); // BGR
            Cv2.Line(src_line, pt1, pt2, scalar, 2, LineTypes.AntiAlias, 0);
            Bitmap bitmap_line = src_line.ToBitmap();
            pictureBox1.Image = bitmap_line;
            // Cv2.ImShow("src",src);
            // Cv2.WaitKey(0);
        }


        /// <summary>
        /// 绘制矩形框
        /// 参数一：src_rectangle，要绘制的图片
        /// 参数二：pt1，矩形左上角坐标
        /// 参数三：pt2，矩形右下角坐标
        /// 参数四：scalar，线段颜色
        /// 参数五：2，线段粗细，越大越粗；-1表示填充
        /// 参数六：LineTypes.Link4，线段的类型
        /// 参数七：0，shift为0
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button3_Click(object sender, EventArgs e)
        {

            Mat src_rectangle = new Mat();
            src_rectangle = Cv2.ImRead(this.picture, ImreadModes.Color);

            // 设置矩形的左上和右下点的位置
            OpenCvSharp.Point pt1 = new OpenCvSharp.Point(10, 20);
            OpenCvSharp.Point pt2 = new OpenCvSharp.Point(20, 50);
            Scalar scalar = new Scalar(0, 255, 0); // BGR
            Cv2.Rectangle(src_rectangle, pt1, pt2, scalar, 2, LineTypes.Link4, 0);

            Bitmap bitmap_rect = src_rectangle.ToBitmap();
            pictureBox1.Image = bitmap_rect;
        }


        /// <summary>
        /// 画圆
        /// 参数一：src_circle，要绘制的图片
        /// 参数二：pt1，圆心坐标
        /// 参数三：50，圆的半径
        /// 参数四：scalar，线段颜色
        /// 参数五：2，线段粗细，越大越粗；-1表示填充
        /// 参数六：LineTypes.Link8，线段的类型
        /// 参数七：0，shift为0
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button4_Click(object sender, EventArgs e)
        {
            Mat src_circle = new Mat();
            src_circle = Cv2.ImRead(this.picture, ImreadModes.Color);

            // 设置圆心位置
            OpenCvSharp.Point pt1 = new OpenCvSharp.Point(100, 60);
            Cv2.Circle(src_circle, pt1, 50, new Scalar(255, 0, 0), 2, LineTypes.Link8, 0);

            Bitmap bitmap_circle = src_circle.ToBitmap();
            pictureBox1.Image = bitmap_circle;
        }

        /// <summary>
        /// 绘制椭圆
        /// 参数一：src_ellipse，处理的图片
        /// 参数二：pt，椭圆的中心点
        /// 参数三：size，半长轴和半短轴的长度
        /// 参数四：270，总共的角度
        /// 参数五：0，开始的角度
        /// 参数六：270，结束的角度
        /// 参数七：scalar，绘制的颜色
        /// 参数八：2，线条的宽度，-1表示填充
        /// 参数九：LineTypes.AntiAlias，绘制线条的类型
        /// 参数十：0，shift为0
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button5_Click(object sender, EventArgs e)
        {
            Mat src_ellipse = new Mat();
            src_ellipse = Cv2.ImRead(this.picture, ImreadModes.Color);

            // 设置椭圆中心位置
            OpenCvSharp.Point pt;
            pt.X = 60;
            pt.Y = 60;
            
            // 设置长半轴和短半轴
            OpenCvSharp.Size size;
            size.Width = 50;
            size.Height = 10;
            
            Scalar scalar = new Scalar(255, 0, 255); // BGR

            Cv2.Ellipse(src_ellipse, pt, size, 270, 0, 270, scalar, 2, LineTypes.AntiAlias, 0);
            Bitmap bitmap_ellipse = src_ellipse.ToBitmap();
            pictureBox1.Image = bitmap_ellipse;
        }


        /// <summary>
        /// 绘制多边形
        /// 参数一：src_poly，待处理的图片
        /// 参数二：pts，绘制多边形坐标，这里是两个多边形pt1和pt2
        /// 参数三：true，是否是闭合的
        /// 参数四：绘制的线段的颜色
        /// 参数五：绘制的线段的宽度
        /// 参数六：LineTypes.AntiAlias，线段的类型
        /// 参数七：0，shift为0
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button6_Click(object sender, EventArgs e)
        {
            Mat src_poly = new Mat();
            src_poly = Cv2.ImRead(this.picture, ImreadModes.Color);

            List<OpenCvSharp.Point> pts1 = new List<OpenCvSharp.Point>
            {
                new OpenCvSharp.Point(30,10),
                new OpenCvSharp.Point(50,50),
                new OpenCvSharp.Point(10,50),
                new OpenCvSharp.Point(30,10)

            };
            List<OpenCvSharp.Point> pts2 = new List<OpenCvSharp.Point>
            {
                new OpenCvSharp.Point(70,10),
                new OpenCvSharp.Point(100,10),
                new OpenCvSharp.Point(100,50),
                new OpenCvSharp.Point(70,50),
                new OpenCvSharp.Point(70,10)
            };

            List<List<OpenCvSharp.Point>> pts = new List<List<OpenCvSharp.Point>>() { pts1, pts2 };

            Cv2.Polylines(src_poly, pts, false, new Scalar(0, 255, 255), 2, LineTypes.AntiAlias, 0);
            Bitmap bitmap_poly = src_poly.ToBitmap();
            pictureBox1.Image = bitmap_poly;
        }


        /// <summary>
        /// 绘制轮廓
        /// 参数一：src_contour，绘制的图片
        /// 参数二：pts，绘制的多边形
        /// 参数三：-1，轮廓索引，看需要绘制那个轮廓，-1表示所有轮廓全都绘制
        /// 参数四：绘制线段的颜色
        /// 参数五：绘制线段的宽度，-1表示填充
        /// 参数六：LineTypes.AntiAlias，线段的类型
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button7_Click(object sender, EventArgs e)
        {
            Mat src_contour = new Mat();
            src_contour = Cv2.ImRead(this.picture, ImreadModes.Color);

            List<OpenCvSharp.Point> pts1 = new List<OpenCvSharp.Point>
            {
                new OpenCvSharp.Point(40,40),
                new OpenCvSharp.Point(40,50),
                new OpenCvSharp.Point(50,50),
                new OpenCvSharp.Point(50,40),
                new OpenCvSharp.Point(45,20),
                new OpenCvSharp.Point(40,40)
            };

            List<List<OpenCvSharp.Point>> pts = new List<List<OpenCvSharp.Point>>() { pts1 };

            Cv2.DrawContours(src_contour, pts, -1, new Scalar(0, 255, 0), -1, LineTypes.AntiAlias);
            Bitmap bitmap_contour = src_contour.ToBitmap();
            pictureBox1.Image = bitmap_contour;
        }


        /// <summary>
        /// 绘制文本内容
        /// 参数一：src_text，待处理的图片
        /// 参数二："beyondyanyu"，绘制的文本字符串内容
        /// 参数三：pt，绘制文字的左上角坐标位置
        /// 参数四：HersheyFonts.Italic，字体的类型
        /// 参数五：3，字体的范围
        /// 参数六：绘制字体的颜色
        /// 参数七：1，绘制线条的宽度
        /// 参数八：LineTypes.AntiAlias，线段的类型
        /// 参数九：false，是否bottomLeftOrigin
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button8_Click(object sender, EventArgs e)
        {
            Mat src_text = new Mat();
            src_text = Cv2.ImRead(this.picture, ImreadModes.Color);

            OpenCvSharp.Point pt = new OpenCvSharp.Point(200, 200);

            Cv2.PutText(src_text, "beyondyanyu", pt, HersheyFonts.Italic, 3, new Scalar(0, 255, 0), 1, LineTypes.Link8, false);

            Bitmap bitmap_text = src_text.ToBitmap();
            pictureBox1.Image = bitmap_text;
        }
    }
}

完整运行效果展示：