The font tool height of i-beam and line-height

[Noitidart]

Dear Mauz, Your font tool is very nice!! I wrote a font tool myself but it is not like yours. You can see my font tool in this firefox addon - https://addons.mozilla.org/en-US/firefox/addon/nativeshot/

I was wondering how are you calcuating line height so well when the user presses the enter key? Also how are you calculating the perfect height of the i-beam? (your ibeam top most seems to line up with top most of letter and ibeam bottom lines up with the bottoms most _ character its amazingly cool)

Thanks I'm going to dig into your code now