How to draw only straight line instead of angled one??

Question

Dear friends,
I saw a very good code posted by guru here(I think is camickr),
But I tried to change it and I hope to draw only straight line instead of angled one, can you help how to do it??
Thanks so much.
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class DrawingArea extends JPanel
     Vector angledLines;
     Point startPoint = null;
     Point endPoint = null;
     Graphics g;
     public DrawingArea()
          angledLines = new Vector();
          setPreferredSize(new Dimension(500,500));
          MyMouseListener ml = new MyMouseListener();
          addMouseListener(ml);
          addMouseMotionListener(ml);
          setBackground(Color.white);
     public void paintComponent(Graphics g)
          // automatically called when repaint
          super.paintComponent(g);
          g.setColor(Color.black);
          AngledLine line;
          if (startPoint != null && endPoint != null)
               // draw the current dragged line
               g.drawLine(startPoint.x, startPoint.y, endPoint.x,endPoint.y);
          for (Enumeration e = angledLines.elements(); e.hasMoreElements();)
               // draw all the angled lines
               line = (AngledLine)e.nextElement();
               g.drawPolyline(line.xPoints, line.yPoints, line.n);
     class MyMouseListener extends MouseInputAdapter
          public void mousePressed(MouseEvent e)
               if (SwingUtilities.isLeftMouseButton(e))
                    startPoint = e.getPoint();
          public void mouseReleased(MouseEvent e)
               if (SwingUtilities.isLeftMouseButton(e))
                    if (startPoint != null)
                         AngledLine line = new AngledLine(startPoint, e.getPoint(), true);
                         angledLines.add(line);
                         startPoint = null;
                         repaint();
          public void mouseDragged(MouseEvent e)
               if (SwingUtilities.isLeftMouseButton(e))
                    if (startPoint != null)
                         endPoint = e.getPoint();
                         repaint();
          public void mouseClicked( MouseEvent e )
               if (g == null)
                    g = getGraphics();
               g.drawRect(10,10,20,20);
     class AngledLine
          // inner class for angled lines
          public int[] xPoints, yPoints;
          public int n = 3;
          public AngledLine(Point startPoint, Point endPoint, boolean left)
               xPoints = new int[n];
               yPoints = new int[n];
               xPoints[0] = startPoint.x;
               xPoints[2] = endPoint.x;
               yPoints[0] = startPoint.y;
               yPoints[2] = endPoint.y;
               if (left)
                    xPoints[1] = startPoint.x;
                    yPoints[1] = endPoint.y;
               else
                    xPoints[1] = endPoint.x;
                    yPoints[1] = startPoint.y;
     public static void main(String[] args)
          JFrame frame = new JFrame("Test angled lines");
          frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
          DrawingArea d = new DrawingArea();
          frame.getContentPane().add( d );
          frame.pack();
          frame.setVisible(true);
}

Answer 1

Change the AngledLine class to store two points instead of 3 points (I would rename the class to be StraightLine). The code is much simpler because you just store the starting and ending points and you don't need to calculate the middle point.