2) DDA - LINE DRAWING ALGORITHM

       

/*<applet code = DDA height = 400 width = 400>

</applet>*/

import java.awt.*;

import java.applet.*;

import java.awt.event.*;

public class DDA extends Applet implements ActionListener {

int x1,x2,y1,y2,step,dx,dy;

float xinc,yinc,X,Y;

Label l1 = new Label("x1 = ");

Label l2 = new Label("x2 = ");

Label l3 = new Label("y1 = ");

Label l4 = new Label("y2 = ");

TextField t1 = new TextField(3);

TextField t2 = new TextField(3);

TextField t3 = new TextField(3);

TextField t4 = new TextField(3);

Button b = new Button("DRAW");

public void init(){

add(l1);

add(t1);

add(l2);

add(t2);

add(l3);

add(t3);

add(l4);

add(t4);

add(b);

b.addActionListener(this);

}

public void paint (Graphics g){

x1=Integer.parseInt(t1.getText());

x2=Integer.parseInt(t2.getText());

y1=Integer.parseInt(t3.getText());

y2=Integer.parseInt(t4.getText());

dx=x2-x1;

dy=y2-y1;

if(Math.abs(dx)>Math.abs(dy))

step=Math.abs(dx);

else

step=Math.abs(dy);

xinc=(float)dx/step;

yinc=(float)dy/step;

X=x1;

Y=y1;

//g.setColor(Color.Red);

g.drawString(".",(int)X,(int)Y);

for(int i=1;i<step;i++)

{

X=X+xinc;

Y=Y+yinc;

//g.setColor(Color.RED);

g.drawString(".",(int)X,(int)Y);

}

}

public void actionPerformed(ActionEvent a)

{

repaint();

}

}