How to find out height of text, given width?

Question

Hello, I apologize in advance for this must be a stupid question, but I just can't seem to find an answer in the docs...
If I have a text (string + font information), and I know how wide the display will be, how do I find the height??
The solution I know of (adapted from camickr code), works, is a hack using a phantom JFrame - see the method showHeight. This is the kind of code that my first college programming professor would call "Mark, your code is ugly and miserable". How to do this right? (or is this the only way)
import java.awt.*;
public class Foo
     public static void main(String[] args)
          showHeight("FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR ", new Font("Arial", Font.BOLD, 12), 100);
     public static void showHeight(String s, Font f,  int width)
          JFrame frame = new JFrame();
          JTextPane txt = new JTextPane();
          Rectangle r = null;
          txt.setFont(f); 
          txt.setText(s);
          Dimension dim = txt.getPreferredSize();
          frame.setContentPane(txt);
          dim.width = width;
          txt.setPreferredSize(dim);
          frame.pack();
          try
               r = txt.modelToView(txt.getDocument().getLength());
          catch (Exception exc)
          System.out.println("height is " + (r.y + r.height));
}

Answer 1

This is not a trivial problem
To start with, you definitely need to know
#1 What Font (family, size, style) are you using? This is assuming you are just using 1 font. More than 1 font makes it much much more complicated.
#2 How are you doing line breaks? Are you doing line breaks just on whitespace characters, or on any character?
Now you need to find out how many lines there are going to be. Start by getting the FontMetrics for the Font. You should use getCharWidth('W') or getCharWidth('0') to get a rough estimate of how many characters any line can contain. Then you need to go through your text and figure out how many lines there are, not using the guess you calculated above, but using FontMetrics.stringWidth()