Implementation of Digital Differential Analyzer (DDL) algorithm in java

Algorithm:

Step 1: Take input two end points (x1, y1) and (x2, y2)

Step 2:Calculate m = dy/dx = (y2-y1)/(x2-x1)

Step 3:Repeat step 4 and 5 while ( x1 <= x2)

Step 4: Color the pixel (x1,y1)

Step 5: if ( m < 1)

x1 = x1 + 1

y1 = y1 + m

else if ( m > 1)

x1 = x1 + (1/m)

y1  = y1 + 1

else

x1 = x1 + 1

y1 = y1 + 1

Source Code:

package today;

import java.awt.Color;

import java.awt.Graphics;

import java.util.Scanner;

import javax.swing.JFrame;

import javax.swing.JPanel;

public class DrawLineAlgorithm {

    public static void main(String[] args) {

        double x1,y1,x2,y2;

        Scanner input = new Scanner(System.in);

        System.out.println("Enter starting co-ordinate:");

        x1 = input.nextDouble();

        y1 = input.nextDouble();

         

        System.out.println("Enter ending co-ordinate:");

        x2 = input.nextDouble();

        y2 = input.nextDouble();

        input.close();

        JFrame frame = new JFrame("My Frame");

        NewClass nc = new NewClass(x1,y1,x2,y2);

        nc.setBackground(Color.WHITE);

        frame.add(nc);

        frame.setSize(500, 500);

        frame.setLocationRelativeTo(null);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.setVisible(true);

         

         

         

    }

}

class NewClass extends JPanel{

    /**

     *

     */

    private static final long serialVersionUID = 1L;

    double x1,y1,x2,y2;

    public NewClass(double x1,double y1,double x2,double y2) {

        this.x1 = x1;

        this.y1 = y1;

        this.x2 = x2;

        this.y2 = y2;

    }

     

    public void paintComponent(Graphics g){

        super.paintComponent(g);

        lineDraw(x1, y1, x2, y2,g);

         

         

         

    }

    public void lineDraw(double x1,double y1,double x2,double y2,Graphics g){

         

        double m;

        m = (y2-y1)/(x2-x1);   

         

        for(int i=0; x1<=x2; i++){

            g.setColor(Color.RED);

            g.fillOval((int)x1, (int)y1, 5, 5);    

            if(m<1){

                x1 = x1 + 1;

                y1 = y1 + m;               

                 

                g.fillOval((int)x1, (int)y1, 5, 5);                    

            }else if(m>1){

                x1 = x1 + (1/m);

                y1 = y1 + 1;

                g.fillOval((int)x1, (int)y1, 5, 5);

            }else{

                x1 = x1 + 1;

                y1 = y1 + 1;

                 

                g.fillOval((int)x1, (int)y1, 5, 5);

            }

             

        }

    }

     

}