Iphone 如何在图像视图中对齐标签？

我有一个滚动视图（IBOutlet）；在这个滚动视图中，我添加了一个imageview。我正在尝试根据图像的大小在图像中添加标签。我的意思是，在图像中放置标签有9个选项：例如TR（右上角）、TC（上中）、C（中）。。。假设我的图像小于iPhone的分辨率，比如300x160。现在，我正在图像视图中加载标签，但工作不正常，标签对齐不正确。 这是我的对齐按钮代码：

-(IBAction)btn_AlignPressed:(UIButton*)sender{
    lbl.tag = sender.tag;
    [imgView addSubview:lbl];
    if (sender.tag == 1) {
        lbl.frame = CGRectMake(0, 0, imgView.frame.size.width, imgView.frame.size.height);
    } else if(sender.tag == 2) {
        lbl.frame = CGRectMake(160-(imgView.frame.size.width/2), 0, imgView.frame.size.width, imgView.frame.size.height);
    } else if(sender.tag == 3) {
        lbl.frame = CGRectMake(320-imgView.frame.size.width, 0, imgView.frame.size.width, imgView.frame.size.height);
    } else if(sender.tag == 4) {
        lbl.frame = CGRectMake(0, 210-(imgView.frame.size.height/2), imgView.frame.size.width, imgView.frame.size.height);
    } else if(sender.tag == 5) {
        lbl.frame = CGRectMake(160-(imgView.frame.size.width/2), 210-(imgView.frame.size.height/2), imgView.frame.size.width, imgView.frame.size.height);
    } else if(sender.tag == 6) {
        lbl.frame = CGRectMake(320-imgView.frame.size.width, 210-(imgView.frame.size.height/2), imgView.frame.size.width, imgView.frame.size.height);
    } else if(sender.tag == 7) {
        lbl.frame = CGRectMake(0, 420-imgView.frame.size.height, imgView.frame.size.width, imgView.frame.size.height);
    } else if(sender.tag == 8) {
        lbl.frame = CGRectMake(160-(imgView.frame.size.width/2), 420-imgView.frame.size.height, imgView.frame.size.width, imgView.frame.size.height);
    } else if(sender.tag == 9) {
        lbl.frame = CGRectMake(320-imgView.frame.size.width, 420-imgView.frame.size.height, imgView.frame.size.width, imgView.frame.size.height);
    }
}

请帮帮我

---

提前感谢。

您只需设置x和y值，还需要调整标签的宽度和高度