程序代码：

 int a, b, c;
        Graphics g;
        Color c2 = new Color();
        Color c3 = new Color();
        Color c4 = new Color();
        Color c5 = new Color();
        private void picturebox1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            Point mouseDownLocation = new Point(e.X, e.Y);
            Bitmap box1 = new Bitmap(pictureBox1.Image);
            int a, b, c;
            a = mouseDownLocation.X;
            b = mouseDownLocation.Y;
            c = pictureBox1.Image.Height;
            Color c1 = Color.FromArgb(0, 0, 0);
            for (int i = b; i < c; i++)
            {
                if (box1.GetPixel(a, i) == c1)
                {
                    return;//找到相应点，返回相应坐标
                    b = i;
                }
            }
            return;//找不到相应点，返回0,0
            c2 = box1.GetPixel(a, b - 1);
            c3 = box1.GetPixel(a, b);
            c4 = box1.GetPixel(a, b + 1);
            c5 = box1.GetPixel(a, b + 2);
           
        }

        private void button1_Click(object sender, EventArgs e)
        {
            int gray2, gray3, gray4, gray5;
            gray2 = (c2.R + c2.G + c2.B) / 3;
            gray3 = (c3.R + c3.G + c3.B) / 3;
            gray4 = (c4.R + c4.G + c4.B) / 3;
            gray5 = (c5.R + c5.G + c5.B) / 3;
            Pen p = new Pen(Color.Black, 1);
            Point pt1 = new Point(b - 1, gray2);
            Point pt2 = new Point(b, gray3);
            Point pt3 = new Point(b + 1, gray4);
            Point pt4 = new Point(b + 2, gray5);
            g.DrawBezier(p, pt1, pt2, pt3, pt4);
        }

寻找点.rar (33.95 KB)