视图不规则圆角

平常view的圆角可以通过以下设置，4个角都生效

  view.layer.cornerRadius = 20;
  view.layer.masksToBounds = YES;

如果需要指定一个角为圆角

• byRoundingCorners 指定某个角为圆弧角
  有如下参数
  typedef NS_OPTIONS(NSUInteger, UIRectCorner) {
  UIRectCornerTopLeft = 1 << 0,
  UIRectCornerTopRight = 1 << 1,
  UIRectCornerBottomLeft = 1 << 2,
  UIRectCornerBottomRight = 1 << 3,
  UIRectCornerAllCorners = ~0UL
  };
• cornerRadii : 为圆角的半径

    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 100, 30) byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomLeft cornerRadii:CGSizeMake(15, 15)];
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = CGRectMake(0, 0, 100, 30);
    maskLayer.path = maskPath.CGPath;
    button.layer.mask = maskLayer;

如图。指定左边上下2个角为圆形

1.png