Drawing a chart or diagram

Question

I'm new to drawing with Java. What I would like to do is draw an event sequence diagram. Basically, a list of endpoints at the top of the diagram, a vertical line below each endpoint, and lines that connect the endpoints in a sequence. I know I'll need to use Graphics and Graphics2D, but I'm not sure where to start.
Anyone have any tips or good references that do something like this?
Thanks.

Answer 1

import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.util.List;
import javax.swing.*;
public class PlotThis
    public PlotThis()
        float[] data = {
            100f, 220f, 12.9f, 65f, 47.3f, 175f, 190f, -18f
        Plotter plotter = new Plotter();
        for(float f : data)
            plotter.plot(f);
        JFrame f = new JFrame("Plot +/- Float Values");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(plotter);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    public static void main(String[] args)
        new PlotThis();
class Plotter extends JPanel
    final float PAD = 25;
    List<Float> dataList;
    public Plotter()
        dataList = new ArrayList<Float>();
        setBackground(Color.white);
        setPreferredSize(new Dimension(400,300));
    public void paintComponent(Graphics g)
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        float width = getWidth();
        float height = getHeight();
        float xStep = (width - 2*PAD)/(dataList.size() - 1);
        float x = PAD;
        float y;
        // scale data
        float max = Collections.max(dataList);
        float min = Collections.min(dataList);
        float vertSpace = height - 2*PAD;
        float yOffset = height - PAD;
        float yDataOffset = (min >= 0 ? min : max > 0 ? 0 : max);
        float scale = vertSpace/(max - min);
        float yOrigin = yOffset +
                            (min > 0 ? 0 : max > 0 ? scale*min : - vertSpace);
        // draw ordinate
        g2.draw(new Line2D.Float(PAD, PAD, PAD, yOffset));
        // draw abcissa
        g2.draw(new Line2D.Float(PAD, yOrigin, width - PAD, yOrigin));
        // label ordinate limits
        g2.drawString(String.valueOf(max), 10, PAD - 10);
        g2.drawString(String.valueOf(min), 10, yOffset + PAD*2/3);
        float lastX = 0, lastY = 0;
        for(int j = 0; j < dataList.size(); j++)
            y = yOrigin - scale * (dataList.get(j) - yDataOffset);
            g2.setPaint(Color.red);
            g2.draw(new Ellipse2D.Float(x - 2, y - 2, 4, 4));
            if( j > 0)
                g2.setPaint(Color.black);
                g2.draw(new Line2D.Float(lastX, lastY, x, y));
            lastX = x;
            lastY = y;
            x += xStep;
    protected void plot(float input)
        dataList.add(input);
        repaint();
}