说明：  Spline曲线拟合的VB源代，根据鼠标的轨迹画出弧线，鼠标在右侧窗体的空白处单击，会留下圆圈，留下一定数量的圆圈后（至少两个）后，点击左上角的“运算曲线”按钮，即可将圆圈圈成线，绘制出图形。
(Spline curve fitting VB source code, based on the trajectory of the mouse to draw an arc, a mouse click on a blank form on the right side, will leave the circle, leaving after a certain number of circles (at least two), click the upper left corner of the operation curve button, you can circle indicates a line drawn graphics.)