ios:给矩形指定角圆角

UIBezierPath *maskPath=  [UIBezierPath bezierPathWithRoundedRect:viewRadius.bounds byRoundingCorners:UIRectCornerBottomLeft|UIRectCornerBottomRight cornerRadii:CGSizeMake(5, 5)];
  CAShapeLayer *maskLayer=[[CAShapeLayer alloc] init];
  maskLayer.frame=viewRadius.bounds;
  maskLayer.path=maskPath.CGPath;
  viewRadius.layer.mask=maskLayer;
  viewRadius.layer.masksToBounds=YES;

typedef NS_OPTIONS(NSUInteger, UIRectCorner) {
    UIRectCornerTopLeft     = 1 << 0,
    UIRectCornerTopRight    = 1 << 1,
    UIRectCornerBottomLeft  = 1 << 2,
    UIRectCornerBottomRight = 1 << 3,
    UIRectCornerAllCorners  = ~0UL
};