Text justify : Font Metrics « 2D Graphics « Java Tutorial

1. Java Tutorial
2. 2D Graphics
3. Font Metrics

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.util.StringTokenizer;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class TextLayoutJustify extends JPanel {
  Dimension d;

  Font f = new Font("fontname", Font.PLAIN, 20);

  FontMetrics fm;

  int fh, ascent;

  int space;

  public static void main(String[] a) {
    JFrame f = new JFrame();
    f.setSize(300, 300);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.getContentPane().add(new TextLayoutJustify());
    f.setVisible(true);
  }
  public void paint(Graphics g) {
    d = getSize();
    g.setFont(f);
    if (fm == null) {
      fm = g.getFontMetrics();
      ascent = fm.getAscent();
      fh = ascent + fm.getDescent();
      space = fm.stringWidth(" ");
    }
    g.setColor(Color.black);
    StringTokenizer st = new StringTokenizer("this is a text. this is a test <BR> this is a text. this is a test");
    int x = 0;
    int nextx;
    int y = 0;
    String word, sp;
    int wordCount = 0;
    String line = "";
    while (st.hasMoreTokens()) {
      word = st.nextToken();
      if (word.equals("<BR>")) {
        drawString(g, line, wordCount, fm.stringWidth(line), y + ascent);
        line = "";
        wordCount = 0;
        x = 0;
        y = y + (fh * 2);
      } else {
        int w = fm.stringWidth(word);
        if ((nextx = (x + space + w)) > d.width) {
          drawString(g, line, wordCount, fm.stringWidth(line), y + ascent);
          line = "";
          wordCount = 0;
          x = 0;
          y = y + fh;
        }
        if (x != 0) {
          sp = " ";
        } else {
          sp = "";
        }
        line = line + sp + word;
        x = x + space + w;
        wordCount++;
      }
    }
    drawString(g, line, wordCount, fm.stringWidth(line), y + ascent);
  }

  public void drawString(Graphics g, String line, int wc, int lineWidth, int y) {
    if (lineWidth < (int) (d.width * .75)) {
      g.drawString(line, 0, y);
    } else {
      int toFill = (int) ((d.width - lineWidth) / wc);
      int nudge = d.width - lineWidth - (toFill * wc);
      StringTokenizer st = new StringTokenizer(line);
      int x = 0;
      while (st.hasMoreTokens()) {
        String word = st.nextToken();
        g.drawString(word, x, y);
        if (nudge > 0) {
          x = x + fm.stringWidth(word) + space + toFill + 1;
          nudge--;
        } else {
          x = x + fm.stringWidth(word) + space + toFill;
        }
      }
    }
  }
}

16.24.Font Metrics
	16.24.1.	Font Metrics: the wealth of dimensional data about a font
	16.24.2.	Font base line
	16.24.3.	Getting Char with based on current font
	16.24.4.	calls stringWidth (String) to center several text messages
	16.24.5.	Center text.
	16.24.6.	Draw text to the left
	16.24.7.	Draw text to the right
	16.24.8.	Draw text to the center
	16.24.9.	Text justify
	16.24.10.	Draw font metrics
	16.24.11.	Display a text in 3 dimensions
	16.24.12.	Obtain FontMetrics of different fonts