java.awt.font letter spacing

Question

Is it possible to increase letter spacing when using java.awt.font ? Something like this:

Font font = new Font("serif", Font.PLAIN, 21);
//Increase the spacing - perhaps with deriveFont()?

BufferedImage image = new BufferedImage(400, 600, BufferedImage.TYPE_INT_RGB);
Graphics2D graphics = image.createGraphics();
graphics.setFont(font);
graphics.drawString("testing",0,0);

Answer 1

You can derive a new font, with an updated tracking attribute:

Map<TextAttribute, Object> attributes = new HashMap<TextAttribute, Object>();
attributes.put(TextAttribute.TRACKING, 0.5);
Font font2 = font.deriveFont(attributes);
gr.setFont(font2);
gr.drawString("testing",0,20);

Answer 2

A generic "center this text in the current font within a container of width w" might be:

    /**
     * Calculates the x-coordinate to use to center the specified message
     * horizontally during a subsequent call to g.drawString().
     * 
     * @param g       - the instance of the Graphics object to use.
     * @param message - the string containing the message to be centered.
     * @param width   - the width of the container to center the message in.
     * @return - the integer x-coordinate to use in a subsequent call to
     *             g.drawString()
     */
    private int centerMessageHorizontal(Graphics g, String message, int width)
    {
        FontMetrics fontMetrics = g.getFontMetrics();
        int textWidth = fontMetrics.stringWidth(message);
        return width / 2 - textWidth / 2;
    }