import javax.swing.*;
import java.awt.*;

public class CustomPanel extends JPanel {

    private int width = 1920;
    private int height = 1080;
    public CustomPanel() {
        setBackground(Color.WHITE);
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics g2 = g.create();
        g2.setColor(Color.BLACK);

        for(int x=0; x<width; x=x+50){
            g2.drawLine(x, 0, x, 1080);
        }
        for(int y=0; y<height; y=y+50){
            g2.drawLine(0, y, 1920, y);
        }
    }
}