I am annotating a mutable attributed string with a strikethrough in objective-c. Using the following code.

```
[MAString addAttribute:NSStrikethroughStyleAttributeName
                     value:[NSNumber numberWithInt:1]
                     range:NSMakeRange(0, [text length])]

```

I am not clear what the value parameter controls and what its possible values are. Does it control thickness? If so, what are the possible values?