IMG_ARC_PIE and IMG_ARC_CHORD are mutually exclusive; IMG_ARC_CHORD just connects the starting and ending angles with a straight line, while IMG_ARC_PIE produces a rounded edge.

• IMG_ARC_PIE和IMG_ARC_CHORD是互斥的;IMG_ARC_CHORD只是用直线连接了起始和结束点,IMG_ARC_PIE则产生圆形边界(如果两个都用,IMG_ARC_CHORD生效)。