label in coordinates

[shalini gnana]

i want to label the co-ordinates in the graph using JLabel.
So far i named the co-ordinates only by using drawstring() method..So,can anyone say me how can i do the same with a Label..Moreover i have to add tool-tip to it.

Any Help!!

[Craig Wood]

import java.awt.*;
import java.awt.geom.Ellipse2D;
import java.text.NumberFormat;
import javax.swing.*;
 
public class LabelOption extends JPanel {
    double[] data = {
        20.2, 12.7, 19.0, 35.75, 16.2, 48.9, 31.0, 10.2
    };
    final int PAD = 20;
    JLabel[] labels;
    NumberFormat nf;
 
    LabelOption() {
        nf = NumberFormat.getInstance();
        nf.setMinimumFractionDigits(1);
        nf.setMaximumFractionDigits(2);
        setLayout(null);
        // For null layout components must be added to the parent
        // Container and must have a size and location specified.
        labels = new JLabel[data.length];
        for(int j = 0; j < labels.length; j++) {
            labels[j] = new JLabel(nf.format(data[j]));
            labels[j].setToolTipText("data["+j+"]");
            // Set size for each label.
            Dimension d = labels[j].getPreferredSize();
            labels[j].setSize(d);
            add(labels[j]);
        }
    }
 
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        int w = getWidth();
        int h = getHeight();
        // Draw axes.
        g2.drawLine(PAD, PAD, PAD, h-PAD);
        g2.drawLine(PAD, h-PAD, w-PAD, h-PAD);
        double xInc = (w - 2*PAD)/(data.length-1);
        double scale = getScale(h);
        // Origin location is (PAD, h-PAD).
        // So y == zero at:
        double y0 = h-PAD;
        g2.setPaint(Color.red);
        // Plot data.
        for(int j = 0; j < data.length; j++) {
            double x = PAD + j*xInc;
            double y = y0 - scale*data[j];
            // Set location for each label.
            Dimension d = labels[j].getPreferredSize();
            labels[j].setLocation((int)(x-d.width/2), (int)y);
            g2.fill(new Ellipse2D.Double(x-1.5, y-1.5, 4, 4));
        }
    }
 
    private double getScale(int h) {
        double max = -Double.MAX_VALUE;
        for(int j = 0; j < data.length; j++) {
            if(data[j] > max)
                max = data[j];
        }
        return (h - 2*PAD)/max;
    }
 
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new LabelOption());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}