Bresenham (midpoint) algorithm (integer DDA) drawing line

package aa;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

/*
 * Line.java
 *
 * Created on 10 , 2007, 11:16 
  
 */

/**
 *
 * @author Sami
 */
public class Line extends MIDlet implements CommandListener
{
    Form form;
    TextField x1Field,x2Field,y1Field,y2Field;
    Command okCommand;
    myCanvas can;
    
    /** Creates a new instance of Line */
    public Line() 
    {
        okCommand=new Command("OK",Command.OK,0);
        form=new Form("Enter The Cordinates");
        x1Field=new TextField("X1: ","",20,TextField.DECIMAL);
        y1Field=new TextField("Y1: ","",20,TextField.DECIMAL);
        x2Field=new TextField("X2: ","",20,TextField.DECIMAL);
        y2Field=new TextField("Y2: ","",20,TextField.DECIMAL);
        form.append(x1Field);
        form.append(y1Field);
        form.append(x2Field);
        form.append(y2Field);
        form.addCommand(okCommand);
        form.setCommandListener(this);
    }

    protected void startApp() throws MIDletStateChangeException 
    {
        Display display=Display.getDisplay(this);
        display.setCurrent(form);      
    }

    protected void pauseApp() {
    }

    protected void destroyApp(boolean b) throws MIDletStateChangeException {
    }

    public void commandAction(Command command, Displayable displayable) 
    {
        if(command.getCommandType()==Command.OK)
        {
            
            int x1=Integer.parseInt(x1Field.getString());
            int y1=Integer.parseInt(y1Field.getString());
            int x2=Integer.parseInt(x2Field.getString());
            int y2=Integer.parseInt(y2Field.getString());
            can=new myCanvas(x1,y1,x2,y2);
           
            Display.getDisplay(this).setCurrent(can);
            can.repaint();
            
        }
    }

}
class myCanvas extends Canvas
{
    public myCanvas(int x1,int y1,int x2,int y2)
    {
        this.x1=x1;
        this.y1=y1;
        this.x2=x2;
        this.y2=y2;
    }
    protected void paint(Graphics g) 
    {
               g.fillRect(0,0,300,300);
        g.setColor(200,23,43);
        int x=0,y=0,dx=0,dy=0;
        int incE,incNE,c;
        
        dx=x2-x1;
        dy=y2-y1;
        c=dy*2-dx;
        incE=dy*2;
        incNE=(dy-dx)*2;
        
        y=y1;
        for(int i=x1;i<x2;i++)
        {
            g.drawLine(i,y,i,y);
            if(c<=0)
            {
                c=c+incE;
            }
            else
            {
                c=c+incNE;
                y++;
            }
        }
        g.drawLine(x2,y,x2,y);
        
    }
    
    int x1=0;
    int x2=0;
    int y1=0;
    int y2=0;
    
}