Plot a 2D Graph as Date being on X-Axis

Question

hi all,
I'm a quite a new bee to Java 2D an would like to know if there are any possibilities to plot a graph in java 2D with X Axis representing Date.
I would need a graph somewhat like
Y
|_____
| _______
|
|_____
|
|________________________ X Axis = Date ->
I have to plot a graph which has a Blocks (consisting of Start & end Dates).
So my graph looks like as shown above and starting point of my graph being the start date of Block & End point being End Date respectively.
Any help in this regard will be highly appreciable.
Thanx
Ati

Answer 1

import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.text.*;
import java.util.*;
import javax.swing.*;
public class PlottingData extends JPanel {
    int[] xVals;
    int[] yVals;
    final int MIN = 50;
    final int MAX = 100;
    final int PAD = 25;
    public PlottingData() {
        // Create a couple of "dates".
        Calendar start = Calendar.getInstance();
        start.setTime(new Date());
        Calendar end = Calendar.getInstance();
        end.setTime(start.getTime());
        end.add(Calendar.DAY_OF_MONTH, 16);
        DateFormat df = new SimpleDateFormat("dd MMM");
        System.out.printf("start = %s  end = %s%n",
                           df.format(start.getTime()),
                           df.format(end.getTime()));
        // Calculate the number of days in between.
        Date difference = new Date(end.getTime().getTime() -
                                   start.getTime().getTime());
        Calendar c = Calendar.getInstance();
        c.setTime(difference);
        int days = c.get(Calendar.DAY_OF_MONTH);
        System.out.println("days = " + days);
        // Instantiate xVals.
        xVals = new int[days];
        // Prepare to count from start to end in days.
        int startDay = start.get(Calendar.DAY_OF_MONTH);
        int endDay = end.get(Calendar.DAY_OF_MONTH);
        Calendar counter = Calendar.getInstance();
        counter.setTime(start.getTime());
        // Initialize elements of xVals array.
        for(int j = 0; j < days; j++) {
            counter.add(Calendar.DAY_OF_MONTH, 1);
            xVals[j] = counter.get(Calendar.DAY_OF_MONTH);
        //System.out.printf("xVals = %s%n", Arrays.toString(xVals));
        // Instantiate yVals array and initialize its elements.
        yVals = new int[days];
        Random seed = new Random();
        for(int j = 0; j < yVals.length; j++) {
            yVals[j] = MIN + seed.nextInt(MAX-MIN+1);  // [50 - 100]
        //System.out.printf("yVals = %s%n", Arrays.toString(yVals));
    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();
        double xInc = (double)(w - 2*PAD)/(xVals.length-1);
        double yInc = (double)(h - 2*PAD)/(MAX - MIN);
        //System.out.printf("xInc = %.1f  yInc = %.1f%n", xInc, yInc);
        // Origin of graph:
        double x0 = PAD;
        double y0 = h-PAD;
        // Draw ordinate.
        g2.draw(new Line2D.Double(PAD, PAD, PAD, h-PAD));
        // Draw tick marks.
        for(int j = MAX-MIN; j >= 0; j -= 10) {
            double y = y0 - j*yInc;
            g2.draw(new Line2D.Double(x0, y, x0-2, y));
        // Label ordinate.
        Font font = g2.getFont();
        FontRenderContext frc = g2.getFontRenderContext();
        LineMetrics lm = font.getLineMetrics("0", frc);
        float height = lm.getAscent() + lm.getDescent();
        for(int j = 0; j <= MAX-MIN; j += 10) {
            String s = String.valueOf(j+MIN);
            float width = (float)font.getStringBounds(s, frc).getWidth();
            float x = (PAD - width)/2;
            float y = (float)(y0 - j*yInc + lm.getDescent());
            g2.drawString(s, x, y);
        // Draw abcissa.
        g2.draw(new Line2D.Double(PAD, h-PAD, w-PAD, h-PAD));
        // Draw tick marks.
        for(int j = 0; j < xVals.length; j++) {
            double x = PAD + j*xInc;
            g2.draw(new Line2D.Double(x, y0, x, y0+2.0));
        // Label abcissa with xVals.
        float sy = h - PAD + (PAD + height)/2 - lm.getDescent();
        for(int j = 0; j < xVals.length; j++) {
            String s = String.valueOf(xVals[j]);
            float width = (float)font.getStringBounds(s, frc).getWidth();
            float x = (float)(PAD + j*xInc - width/2);
            g2.drawString(s, x, sy);
        // Plot data.
        g2.setPaint(Color.red);
        for(int j = 0; j < yVals.length; j++) {
            double x = x0 + j*xInc;
            double y = y0 - (yVals[j] - MIN)*yInc;
            g2.fill(new Ellipse2D.Double(x-1.5, y-1.5, 4, 4));
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new PlottingData());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
}