No, because supporting a character means knowing all the metadata about it, not merely drawing it on the screen. You have to know whether it's a letter or a number or punctuation so that you can match against it in regular expressions, or do word breaking when you double click on it, etc. You have to know its bidi class so that you can render it in the right direction when putting it on the screen. You have to know the shaping rules so that apply when it's near other characters. None of that comes from your fonts; fonts just have glyphs in them. All the other metadata comes from the Unicode specification.
