用 UIBezierPath设置任意方向的圆角
UIView *view = [[UIView alloc] init];
view.backgroundColor = [UIColor orangeColor];
view.frame = CGRectMake(100, 100, 100, 100);
[self.view addSubview:view];
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:UIRectCornerTopLeft|UIRectCornerTopRight cornerRadii:CGSizeMake(10, 10)];
CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.frame = view.bounds;
maskLayer.path = maskPath.CGPath;
view.layer.mask = maskLayer;
typedef NS_OPTIONS(NSUInteger, UIRectCorner) {
UIRectCornerTopLeft = 1 << 0,
UIRectCornerTopRight = 1 << 1,
UIRectCornerBottomLeft = 1 << 2,
UIRectCornerBottomRight = 1 << 3,
UIRectCornerAllCorners = ~0UL
};