通过用户交互的方式形成Delauny三角网，也可以通过读取点（txt）文件画tin并且输出三角网的每条边的起点，终点，线的斜率和截距-Using the way that users control the positions of the points so as to draw the TIN under the rule of Delauny.Besides,it allows the users that call the txt file which records the infor