《学习OpenCV(中文版)》

作者：（美）布拉德斯基（Bradski，G.）
（美）克勒（Kaehler，A.） 著
出版社：清华大学出版社
出版时间：2009年10月

http://cn.voidcc.com/question/p-pneulhvn-qa.html

一、MouseUp事件

• 当鼠标移动时，鼠标指针所走过的每个像素都不会得到MouseMove事件。你会以相当一致的时间间隔得到它们，所以鼠标移动的速度越快，得到的点就越远。这个你不能做太多的细节。

• MouseUp事件中取、存储最后一个点的位置，并在最后一个点和最后一个点之间的每个点绘制一个矩形。

二、在画布内移动动态绘制矩形

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using OpenCvSharp;
using OpenCvSharp.Extensions;


namespace Ky_CvRoi
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        public string SourceFname = @"d:\2022视觉文件夹\安柏.JPG";
        public Mat S0 = Cv2.ImRead(@"d:\2022视觉文件夹\安柏.JPG", ImreadModes.Unchanged);
        public OpenCvSharp.Point p1 = new OpenCvSharp.Point(-1, -1);
        public OpenCvSharp.Point p2 = new OpenCvSharp.Point(-1, -1);
        bool mouseDown = false; 

        #region  定义一个发送接收图像数据的全局变量SendPicData
        public Mat SendPicData  
        {
            get { return BitmapConverter.ToMat((Bitmap)pictureBox1.Image); }
            set { pictureBox1.Image = value.ToBitmap(); }
        }
        #endregion


        private void Form1_Load(object sender, EventArgs e)
        {
            pictureBox1.Image = S0.ToBitmap();
        }

        private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
        {
            mouseDown = true;
            if (mouseDown)
            {
                p1.X = e.X;
                p1.Y = e.Y;
                textBox1.Text = textBox1.Text + "p1=(" + e.X.ToString() + " , " + e.Y.ToString() + ")\r\n";
            }
        }


        private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
        {
            mouseDown = false;
                int w1;
                int h1;
                if ((p1.X >= 0) && (p1.Y >= 0))
                {
                    p2.X = e.X;
                    p2.Y = e.Y;
                    textBox1.Text = textBox1.Text + "p2=(" + e.X.ToString() + " , " + e.Y.ToString() + ")\r\n";
                    w1 = p2.X - p1.X;
                    h1 = p2.Y - p1.Y;
                    if (p2.X < p1.X)
                    {
                        w1 = p1.X - p2.X;
                    };
                    if (p2.Y < p1.Y)
                    {
                        h1 = p1.Y - p2.Y;
                    }
                }

                OpenCvSharp.Scalar scalar = new OpenCvSharp.Scalar(0, 200, 200);
                S0.Rectangle(p1, p2, scalar,2);
                pictureBox1.Image = OpenCvSharp.Extensions.BitmapConverter.ToBitmap(S0);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            string path = @"d:\2022视觉文件夹\安柏.JPG";
            pictureBox1.Image = new Bitmap(path);
            S0 = new Mat(path);
            pictureBox1.Image = OpenCvSharp.Extensions.BitmapConverter.ToBitmap(S0);
        }
    }
}

三、运行结果