Re: FontMetrics help needed

Knute Johnson <>
Thu, 17 Aug 2006 19:55:08 -0700
David Cogen wrote:

Hi, this seems like a "chicken and egg" problem, but I am sure there is
a way to do this:

In order to compute the height of a JPanel I want to instantiate I need
to know the height of a line of text, which I could do using

But that doesn't work until I call JPanel.setVisible() (null pointer

But before I can make it visible I need to know its size!

Any suggestions?

Very easy if you can use 1.5 or later.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class test3 extends JPanel {
     String str = "Now is the time for all good men to come to the aid";
     int height;

     public test3(Font font) {
         FontMetrics fm = getFontMetrics(font);
         height = fm.getHeight();
         int width = fm.stringWidth(str);
         setPreferredSize(new Dimension(width,height));

     public void paintComponent(Graphics g) {

     public static void main(String[] args) {
         Runnable r = new Runnable() {
             public void run() {
                 test3 t3 = new test3(new Font("Arial",Font.BOLD,24));
                 JFrame f = new JFrame();


Knute Johnson
email s/nospam/knute/

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