这是老外写的一个类似于书法的画笔，特别是占用内存特别的少，看了好久源代码，才差不多了解，对以后开发画板功能有很大的帮助。 1 笔触移动平滑 2 笔尖跟随鼠标的拖放速度变化-This is written by a foreigner like calligraphy brush, especially a special memory for less, read the source code for a long time, it is almost understood that