切去某个角弧度

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(120, 50, 100, 100)];
    view.backgroundColor = [UIColor blueColor];
    [self.view addSubview:view];
    
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerTopRight cornerRadii:CGSizeMake(20, 20)];
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = view.bounds;
    maskLayer.path = maskPath.CGPath;
    view.layer.mask = maskLayer;

 效果图