无论如何就是找不到方法🤣

/**
 Rounds a new image with a given corner size.
 
 @param radius  The radius of each corner oval. Values larger than half the
                rectangle's width or height are clamped appropriately to half
                the width or height.
 */
- (nullable UIImage *)imageByRoundCornerRadius:(CGFloat)radius;

原来是因为,Swift里省略了头部image,调用这个方法要这样调用

image.ByRoundCornerRadius(5)

我可太菜了哈哈哈，记录一下