Java center text in rectangle

Question

I use drawString() method to draw string using Graphics, but I want to center my text in a rectangle. How should I do that?

Your title states, you're using `JTextField`, but not your question. So which is true? — Mordechai, Jan 11 '13 at 18:51
Your title is: *Java center text in textfield* but your post says: *I use `drawString()` method to draw string on Graphics, but I want to center my text in a rectangle. How should I do that?* how does this correspond — David Kroukamp, Jan 11 '13 at 18:59
To correct my question: I have a rectangle somewhere in the JFrame.... I want to draw string centered in that rectangle. How should i do that? — Luka Tiger, Jan 11 '13 at 23:00
Read about the [`FontMetrics`](http://docs.oracle.com/javase/6/docs/api/java/awt/FontMetrics.html) class — Mordechai, Jan 11 '13 at 18:53

Gilbert Le Blanc · Answer 1 · 2013-01-11T20:37:54.470

32

I've used this to center text on a JPanel

        Graphics2D g2d = (Graphics2D) g;
        FontMetrics fm = g2d.getFontMetrics();
        Rectangle2D r = fm.getStringBounds(stringTime, g2d);
        int x = (this.getWidth() - (int) r.getWidth()) / 2;
        int y = (this.getHeight() - (int) r.getHeight()) / 2 + fm.getAscent();
        g.drawString(stringTime, x, y);

edited Jan 11 '13 at 20:37

answered Jan 11 '13 at 19:03

Gilbert Le Blanc

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Centring text vertically is little more involved, because of the text ascent and the way that text is rendered. From memory, it should be more like y = ((getHeight() - fm.getHeight()) / 2) + fm.getAscent(); ... Try drawing a line across the components centre line and compare the two method, if my memory is serving me well, I believe this will be more properly centered ... +1 – MadProgrammer Jan 11 '13 at 20:12
1

You might also like to have a read through [this](http://stackoverflow.com/questions/1055851/how-do-you-draw-a-string-centered-vertically-in-java) – MadProgrammer Jan 11 '13 at 20:39
1

I think I liked the appearance better when I centered the baseline. :-) – Gilbert Le Blanc Jan 11 '13 at 20:42
1

It comes down to what you want, I prefer the text to be vertically based on the visual centre position, but that's just me ;) – MadProgrammer Jan 11 '13 at 21:24

score 21 · Answer 2 · answered Jan 11 '13 at 21:53

Centering text has a lot of "options". Do you center absolutely or based on the base line??

enter image description here

Personally, I prefer the absolute center position, but it depends on what you are doing...

public class CenterText {

    public static void main(String[] args) {
        new CenterText();
    }

    public CenterText() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Test");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }

        });
    }

    public class TestPane extends JPanel {

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            int height = getHeight();
            String text = "This is a test xyx";

            g.setColor(Color.RED);
            g.drawLine(0, height / 2, getWidth(), height / 2);

            FontMetrics fm = g.getFontMetrics();
            int totalWidth = (fm.stringWidth(text) * 2) + 4;

            // Baseline
            int x = (getWidth() - totalWidth) / 2;
            int y = (getHeight() - fm.getHeight()) / 2;
            g.setColor(Color.BLACK);

            g.drawString(text, x, y + ((fm.getDescent() + fm.getAscent()) / 2));

            // Absolute...
            x += fm.stringWidth(text) + 2;
            y = ((getHeight() - fm.getHeight()) / 2) + fm.getAscent();
            g.drawString(text, x, y);

        }

    }

}

Java center text in rectangle

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