C＃LASER盘旋手势使用

Question

在我的程序中，用户可以在大型显示器上与LASER指针进行交互，LASER将通过在其周围做一个圆圈来执行打开文件等操作。

我的代码正在检测画一个圆圈，我想预测用户在连续移动期间何时开始制作这个圆圈。我想找到用户开始制作圆圈的时间和这个圆圈的起点。

 Bitmap b = new Bitmap(pictureBox1.Image);
       Rectangle a = (Rectangle)r;
       global.PointX[global.LastIndex] = a.Location.X;
       global.PointY[global.LastIndex] = a.Location.Y;
       global.LastIndex++;
       Pen pen1 = new Pen(Color.FromArgb(160, 255, 160), 3);
       Graphics g2 = Graphics.FromImage(b);
       pen1 = new Pen(color, 3);
       SolidBrush b5 = new SolidBrush(color);


       Font f = new Font(Font, FontStyle.Bold);

       g2.DrawString("o", f, b5, a.Location);
       g2.Dispose();
       pictureBox1.Image = (System.Drawing.Image)b;

       if (global.LastIndex > 1)
       {
               if (Math.Sqrt(Math.Pow(global.PointX[global.LastIndex - 1] - global.PointX[0], 2) + Math.Pow(global.PointY[global.LastIndex - 1] - global.PointY[0], 2)) < Math.Sqrt(Math.Pow(global.PointX[global.LastIndex - 2] - global.PointX[0], 2) + Math.Pow(global.PointY[global.LastIndex - 2] - global.PointY[0], 2)))
               {
                   global.CloseToBeCircle = true;
               }
               global.angle[global.LastIndex] = System.Math.Atan2(global.PointY[global.LastIndex - 2] - global.PointY[global.LastIndex - 1], global.PointX[global.LastIndex - 2] - global.PointX[global.LastIndex - 1]) * 180 / System.Math.PI;

               if (global.angle[global.LastIndex - 1] < 0)
                   global.angle[global.LastIndex - 1] += 360;

               if (global.angle[global.LastIndex - 1] > 270 && global.angle[global.LastIndex - 2] < 90)
               {
                   global.angle[global.LastIndex - 2] += 360;
               }
               else if (global.angle[global.LastIndex - 2] > 270 && global.angle[global.LastIndex - 1] < 90)
               {
                   global.angle[global.LastIndex - 1] += 360;
               }

               if (global.angle[global.LastIndex - 1] - global.angle[global.LastIndex - 2] > 0)
               {
                   global.IsPositive[global.PositiveIndex++] = true;

               }
               else if (global.angle[global.LastIndex - 1] - global.angle[global.LastIndex - 2] < 0)
                   global.IsNegative[global.NegativeIndex++] = true;

               //if (global.IsPositive[15] == true || global.IsNegative[15] == true)
               if (global.CloseToBeCircle)
               {
                   if ((global.PositiveIndex > global.NegativeIndex && global.NegativeIndex == 0) || (global.NegativeIndex > global.PositiveIndex && global.PositiveIndex == 0))
                   {
                       if (Math.Pow(global.PointX[global.LastIndex - 1] - global.PointX[0], 2) <= 25 || Math.Pow(global.PointY[global.LastIndex - 1] - global.PointY[0], 2) <= 25)
                       {
                           flush();
                           this.Invoke((MethodInvoker)delegate
                           {
                               MessageBox.Show("Circle");
                           });
                       }
                   }
               }