Java2D Graphics anti-aliased

Question

I am new to Java and trying to use Java2D Graphics to create a Image. But the output is coming as anti-aliased. I tried many ways to rectify it but doesn't work. The characters are getting distorted or jagged.

public BufferedImage createNameOnButton(String label) {
    int messageWidth = 0;
    Font font = new Font("Arial", Font.PLAIN, 11);

    BufferedImage bi = new BufferedImage(
        10, 10, BufferedImage.TYPE_INT_RGB);

    Graphics2D g2d = (Graphics2D) bi.getGraphics();
    g2d.setRenderingHint(
        RenderingHints.KEY_ANTIALIASING,
        RenderingHints.VALUE_ANTIALIAS_ON);
    g2d.setRenderingHint(
        RenderingHints.KEY_TEXT_ANTIALIASING,
        RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
    g2d.setRenderingHint(
        RenderingHints.KEY_FRACTIONALMETRICS,
        RenderingHints.VALUE_FRACTIONALMETRICS_ON);
    g2d.setFont(font);

    bi = g2d.getDeviceConfiguration()
        .createCompatibleImage(500, 30, Transparency.BITMASK);
    FontMetrics fm = bi.getGraphics().getFontMetrics(font);
    int messageHeight = fm.getHeight() - fm.getDescent();
    for (char ch : label.toCharArray()) {
        messageWidth += fm.charWidth(ch);
    }

    bi = bi.getSubimage(50, 0, messageWidth + 10, fm.getHeight());
    Graphics g = bi.getGraphics();
    g.setColor(Color.black);
    AttributedString as = new AttributedString(label);
    as.addAttribute(TextAttribute.FONT, font);
    g.drawString(as.getIterator(), 5, messageHeight);
    g2d.dispose();
    g.dispose();
    return bi;
}

Can anyone please help me to rectify the error?

Answer 1

Assuming you actually want smooth (non-aliased) text, TextLayout may make this easier. The FontRenderContext constructor can manage the anti-aliasing and fractional metrics settings.

Addendum: Using g2d.setColor(Color.blue) seems to produce the expected effect.

Addendum: On Mac OS X, the Pixie application in /Developer/Applications/Graphics Tools/ is convenient for examining the anti-alias pixels. On other platforms, Zoom may be used.

/** @see https://stackoverflow.com/questions/4285464 */
public class BITest extends JPanel {

    private BufferedImage image = createNameOnButton("Sample");

    public BITest() {
        this.setPreferredSize(new Dimension(
            image.getWidth(), image.getHeight()));
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(image, 0, 0, null);
    }

    public BufferedImage createNameOnButton(String label) {
        Font font = new Font("Arial", Font.PLAIN, 64);
        FontRenderContext frc = new FontRenderContext(null, true, true);
        TextLayout layout = new TextLayout(label, font, frc);
        Rectangle r = layout.getPixelBounds(null, 0, 0);
        System.out.println(r);
        BufferedImage bi = new BufferedImage(
            r.width + 1, r.height + 1,
            BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2d = (Graphics2D) bi.getGraphics();
        g2d.setColor(Color.blue);
        layout.draw(g2d, 0, -r.y);
        g2d.dispose();
        return bi;
    }

    private void display() {
        JFrame f = new JFrame("BITest");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setUndecorated(true);
        f.add(this);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new BITest().display();
            }
        });
    }
}

Answer 2

I found that just this line does the trick:

  g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);

After that, just use drawString().

Answer 3

As Traroth mentioned it is more than likely due to

g2d.setRenderingHint(
    RenderingHints.KEY_ANTIALIASING,
    RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(
    RenderingHints.KEY_TEXT_ANTIALIASING,
    RenderingHints.VALUE_TEXT_ANTIALIAS_ON);

Instead this should be

g2d.setRenderingHint(
    RenderingHints.KEY_ANTIALIASING,
    RenderingHints.VALUE_ANTIALIAS_OFF);
g2d.setRenderingHint(
    RenderingHints.KEY_TEXT_ANTIALIASING,
    RenderingHints.VALUE_TEXT_ANTIALIAS_OFF);