TextLayoutWithCarets.java Source code

Introduction

Here is the source code for TextLayoutWithCarets.java

Source

import java.awt.BasicStroke;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.font.FontRenderContext;
import java.awt.font.TextAttribute;
import java.awt.font.TextHitInfo;
import java.awt.font.TextLayout;
import java.awt.geom.AffineTransform;
import java.text.AttributedCharacterIterator;
import java.text.AttributedString;

import javax.swing.JFrame;
import javax.swing.JLabel;

public class TextLayoutWithCarets extends JLabel {
    private TextHitInfo mHit;

    private TextLayout mLayout;

    private boolean mInitialized = false;

    public TextLayoutWithCarets() {
        addKeyListener(new KeyListener() {
            public void keyPressed(KeyEvent ke) {
                if (ke.getKeyCode() == KeyEvent.VK_RIGHT) {
                    mHit = mLayout.getNextRightHit(mHit.getInsertionIndex());
                    if (mHit == null)
                        mHit = mLayout.getNextLeftHit(1);
                    repaint();
                } else if (ke.getKeyCode() == KeyEvent.VK_LEFT) {
                    mHit = mLayout.getNextLeftHit(mHit.getInsertionIndex());
                    if (mHit == null)
                        mHit = mLayout.getNextRightHit(mLayout.getCharacterCount() - 1);
                    repaint();
                }
            }

            public void keyTyped(KeyEvent arg0) {
                // TODO Auto-generated method stub

            }

            public void keyReleased(KeyEvent arg0) {
                // TODO Auto-generated method stub

            }
        });

    }

    private void initialize(Graphics2D g2) {
        String s = "Java Source and Support.";
        // Create a plain and italic font.
        int fontSize = 32;
        Font font = new Font("Lucida Sans Regular", Font.PLAIN, fontSize);
        Font italicFont = new Font("Lucida Sans Oblique", Font.ITALIC, fontSize);
        // Create an Attributed String
        AttributedString as = new AttributedString(s);
        as.addAttribute(TextAttribute.FONT, font);
        as.addAttribute(TextAttribute.FONT, italicFont, 2, 5);
        // Get the iterator.
        AttributedCharacterIterator iterator = as.getIterator();
        // Create a TextLayout.
        FontRenderContext frc = g2.getFontRenderContext();
        mLayout = new TextLayout(iterator, frc);

        mHit = mLayout.getNextLeftHit(1);

        // Respond to left and right arrow keys.

        mInitialized = true;
    }

    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);

        if (mInitialized == false)
            initialize(g2);

        float x = 20, y = 80;
        mLayout.draw(g2, x, y);

        // Create a plain stroke and a dashed stroke.
        Stroke[] caretStrokes = new Stroke[2];
        caretStrokes[0] = new BasicStroke();
        caretStrokes[1] = new BasicStroke(1, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND, 0, new float[] { 4, 4 },
                0);

        // Now draw the carets
        Shape[] carets = mLayout.getCaretShapes(mHit.getInsertionIndex());
        for (int i = 0; i < carets.length; i++) {
            if (carets[i] != null) {
                AffineTransform at = AffineTransform.getTranslateInstance(x, y);
                Shape shape = at.createTransformedShape(carets[i]);
                g2.setStroke(caretStrokes[i]);
                g2.draw(shape);
            }
        }
    }

    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.getContentPane().add(new TextLayoutWithCarets());
        f.setSize(350, 250);
        f.setVisible(true);

    }

}