iOS-把某个角切成圆角

//把 view2 的 左下角 和 右下角的直角切成圆角
    UIView *view2 = [[UIView alloc] initWithFrame:CGRectMake(120,10,80,80)];
    view2.backgroundColor = [UIColor redColor];
    [self.view addSubview:view2];
    
    //设置切哪个直角
//    UIRectCornerTopLeft     = 1 << 0,  左上角
//    UIRectCornerTopRight    = 1 << 1,  右上角
//    UIRectCornerBottomLeft  = 1 << 2,  左下角
//    UIRectCornerBottomRight = 1 << 3,  右下角
//    UIRectCornerAllCorners  = ~0UL     全部角
    //得到view的遮罩路径
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view2.bounds byRoundingCorners:UIRectCornerBottomLeft | UIRectCornerBottomRight cornerRadii:CGSizeMake(10,10)];
    //创建 layer
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = view2.bounds;
    //赋值
    maskLayer.path = maskPath.CGPath;
    view2.layer.mask = maskLayer;