How to adjust width of TTStyledTextLabel?

I am implementing an IM app on iOS. I found that three20 library has a TTStyledTextLabel which provides cool features like showing images and url links. However I want to embed the TTStyledTextLabel in a message bubble (just like the sms app shipped with iphone does), where I need the label to adjust its size according to the text length. I found that TTStyledTextLabel can adjust its height according to its width, but I don't know how to make it shrink horizontally when the text is very short and can't fill up a whole line. Any suggestions?

I think I have a slightly better solution: I get the rootFrame of the ttstyledtext and iterate over its sibling frames to find the max width.

It works like this:

    TTStyledTextLabel* label = [[TTStyledTextLabel alloc] init];
    label.text = [TTStyledText textFromXHTML:myTextToBeDisplayed];
    [label sizeToFit];
    CGFloat maxWidth = 0;
    TTStyledFrame *f = label.text.rootFrame;
    while (f) {
        int w = f.x + f.width;
        if (w > maxWidth) {
            maxWidth = w;
        }
        f = f.nextFrame;
    }
    return CGSizeMake(maxWidth, label.height);