Doesn't seem to work with printf

[stewartjohnson]

When I'm using rainbow to add colour to strings that are displayed with printf, it seems to mess up the alignments. Example using irb below. Is there anything I can do to work around this?

stewart@host:~$ irb
ruby-1.9.2-head > require "rainbow" 
 => true
ruby-1.9.2-head > printf("%20s\n", "foo")
                 foo # this is indented by 17 chars (correctly)
 => nil
ruby-1.9.2-head > printf("%20s\n", "foo".foreground(:red))
        foo # this is coloured, but only indented by 8 chars
 => nil 
ruby-1.9.2-head > printf("%20s\n", "foo".foreground(:red).background(:white))
   foo # this is coloured, but it's only indented by 3 chars
 => nil

[ku1ik]

I don't think there is anything I can change in rainbow to resolve this issue. Looks like printf is counting also ANSI escape codes as normal characters when doing alignment.

The only solution I can think of now is to monkey-patch Kernel#printf, but this sounds like a dangerous thing to do. I won't do this in rainbow, but If you're brave you can try it by yourself :)