// TLineBreakMeasurer.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.font.*;
import java.text.*;
import java.awt.geom.*;

public class TLineBreakMeasurer extends JFrame {
    // 1. Constructor
    public TLineBreakMeasurer(String title) {
        super(title);
        setBackground(Color.white);
    }

    // 2. The main method...
    public static void main(String arg[]) {
        TLineBreakMeasurer frame = new TLineBreakMeasurer("TLineBreakMeasurer");
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        frame.getContentPane().add("Center", new DisplayPanel());
        frame.pack();
        frame.setSize(new Dimension(350,400));
        frame.show();
    }
}

// 3. Definition of the display panel class
class DisplayPanel extends JPanel {
    String text = "This is a long string of Java 2D text "
                + "that can wrap futher to new rows when the "
                + "user reduces the width of this window!!! "
                + "So try to reduce the window and see the effect, "
                + "especially if you have a long word like "
                + "blablablablablablablablabla.";
    AttributedString attribString;
    AttributedCharacterIterator attribCharIterator;

    public DisplayPanel() {
        // 4. Prepare the display panel with suitable size and background
        setBackground(Color.white);
        setSize(350, 400);

        // 5. Create the attributed string object using the given text, and
        // assign a new font and foreground color.
        attribString = new AttributedString(text);
        attribString.addAttribute(TextAttribute.FOREGROUND,
                                  Color.blue,
                                  0, text.length()); // Start and end indexes.
        Font font = new Font("sanserif", Font.ITALIC, 20);
        attribString.addAttribute(TextAttribute.FONT, font, 0, text.length());
    }

    // 6. The paintComponent method...
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;

        // 7. Retrieve the character iterator from the attributed string
        attribCharIterator = attribString.getIterator();

        // 8. Create a font render contex object and line break measurer.
        FontRenderContext frc = new FontRenderContext(null, false, false);
        LineBreakMeasurer lbm = new LineBreakMeasurer(attribCharIterator, frc);

        // 9. Perform the layout using the line break measurer, and 
        // draw the text on different rows in a 'while' loop.
        int x = 10, y = 20; // Left and top margins
        int w = getWidth(), h = getHeight(); // Window dimensions
        // Leave 15 pixels before the right edge of the the window. 
        float wrappingWidth = w - 15;

        while (lbm.getPosition() < text.length()) {
            // Retrieve the text layout for the wrapping width
            TextLayout layout = lbm.nextLayout(wrappingWidth);

            // Compute the base line 
            y += layout.getAscent();

            // Draw the string from the layout
            layout.draw(g2, x, y);

            //Go to the line passing through the acent of characters.
            y += layout.getDescent() + layout.getLeading();
        }
    }
}