Java2D graphics -GIS(pls help)

Question

Hey!...
My Applet is basically split into two parts....a JTree on the left and a text area on the right...i have two arrays...x3Points and y3Points that contain the map co-ordinates that are retrieved from the server side. They contain data like following for example.....
x3points (-119.169)
y3points (45.7601)
x3points (-119.259)
y3points (45.8506)
I am trying to display these points in the text area using the following code syntax....but nothing show up :(...can neone help pls!
for(int i=0;i<x3Points.length-1;i++)
g2.draw(new Line2D.Double(x3Points,y3Points,x3Points[i+1],y3Points[i+1]));
Thank You...An

Answer 1

I don't think you can paint graphics inside a JTextArea.
import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.util.List;
import javax.swing.*;
import javax.swing.tree.*;
public class ShowingPoints {
  public static void main(String[] args) {
    TreeNode root = new DefaultMutableTreeNode("Root Node");
    TreeModel model = new DefaultTreeModel(root);
    JTree tree = new JTree(model);
    tree.setPreferredSize(new Dimension(200,200));
    double[] xPoints = {
      -20.0, 15.5, 84.1, 65.3
    double[] yPoints = {
      12.9, 15.3, 19.0, 44.3
    LinePlotter lp = new LinePlotter(xPoints, yPoints);
    lp.setPreferredSize(new Dimension(200,200));
    JPanel panel = new JPanel();
    panel.add(tree);
    panel.add(lp);
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.getContentPane().add(new JScrollPane(panel));
    f.setSize(400,300);
    f.setLocation(300,300);
    f.setVisible(true);
class LinePlotter extends JPanel {
  List xData, yData;
  final double PAD = 25.0;
  public LinePlotter(double[] xPoints, double[] yPoints) {
    xData = new ArrayList();
    yData = new ArrayList();
    for(int i = 0; i < xPoints.length; i++) {
      xData.add(new Double(xPoints));
yData.add(new Double(yPoints[i]));
setBackground(Color.white);
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
if(xData.size() == 0 || yData.size() == 0 ||
xData.size() % 2 != 0 || yData.size() % 2 != 0 || xData.size()/yData.size() != 1)
return;
double
xMin = ((Double)Collections.min(xData)).doubleValue(),
xMax = ((Double)Collections.max(xData)).doubleValue(),
yMin = ((Double)Collections.min(yData)).doubleValue(),
yMax = ((Double)Collections.max(yData)).doubleValue();
double
width = getWidth(),
height = getHeight(),
yOffset = height - PAD,
yDataOffset = (yMin >= 0 ? yMin : yMax > 0 ? 0 : yMax),
xDataOffset = (xMin >= 0 ? xMin : xMax > 0 ? 0 : xMax),
vertSpace = height - 2*PAD,
vScale = vertSpace/(yMax - yMin),
yOrigin = yOffset + (yMin > 0 ? 0 : yMax > 0 ? vScale*yMin : - vertSpace),
horizSpace = width - 2*PAD,
hScale = horizSpace/(xMax - xMin),
xOrigin = PAD - (xMin >= 0 ? 0 : xMax > 0 ? hScale*xMin : - horizSpace);
double x1, y1, x2, y2;
for(int i = 0; i < xData.size(); i += 2) {
x1 = xOrigin + hScale*(((Double)xData.get(i)).doubleValue() - yDataOffset);
y1 = yOrigin - vScale*(((Double)yData.get(i)).doubleValue() - yDataOffset);
x2 = xOrigin + hScale*(((Double)xData.get(i + 1)).doubleValue() - xDataOffset);
y2 = yOrigin - vScale*(((Double)yData.get(i + 1)).doubleValue() - yDataOffset);
g2.draw(new Line2D.Double(x1, y1, x2, y2));