Bresenham.java

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.WindowConstants;
 
public class Bresenham {
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        f.setTitle("Bresenham");
 
        f.getContentPane().add(new BresenhamPanel());
        f.pack();
        
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}
 
class BresenhamPanel extends JPanel {
    //line width
    private final int pixelSize = 5;
 
    BresenhamPanel() {
        setPreferredSize(new Dimension(600, 600));
        setBackground(Color.RED);
    }
 
    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        
        //***DRAW LINE***//
        drawLine(g, 0, 0, 0, 100);
        
        g.setColor(Color.white);   //set line color
        drawLine(g, 100, 100, 10, 30);
        
        g.setColor(Color.blue);   //set line color
        drawLine(g, 50, 50, 500, 400);
        
        g.setColor(Color.GREEN);   //set line color
        drawLine(g, 500, 50, 250, 300);
        
        g.setColor(new Color(255,0,255));   //set line color
        drawLine(g, 250, 20, 250, 300);
    }
 
    private void plot(Graphics g, int x, int y) {
        g.fillOval(x, y, pixelSize, pixelSize);
    }
 
    //Bresenham algorithm
    private void drawLine(Graphics g, int x1, int y1, int x2, int y2) {
        // delta of exact value and rounded value of the dependent variable
        int d = 0;
 
        int dx = Math.abs(x2 - x1);
        int dy = Math.abs(y2 - y1);
 
        int dx2 = 2 * dx; // slope scaling factors to
        int dy2 = 2 * dy; // avoid floating point
 
        int ix = x1 < x2 ? 1 : -1; // increment direction
        int iy = y1 < y2 ? 1 : -1;
 
        int x = x1;
        int y = y1;
 
        if (dx >= dy) {
            while (true) {
                plot(g, x, y);
                if (x == x2)
                    break;
                x += ix;
                d += dy2;
                if (d > dx) {
                    y += iy;
                    d -= dx2;
                }
            }
        } else {
            while (true) {
                plot(g, x, y);
                if (y == y2)
                    break;
                y += iy;
                d += dx2;
                if (d > dy) {
                    x += ix;
                    d -= dy2;
                }
            }
        }
    }
}