mfc实现的二次B样条曲线实例，点击所有的点之后，点击生成按钮，自动实现绘制二次B样条曲线。 此实例是我费了很大劲才找来的，对研究二次B样条曲线绘制会有很大帮助。-mfc realized quadratic B-spline curve example, click on all the points, click generate button, automatically rendering the second B-spline curve. This example is my g