wordle/src/GUI.java

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.util.Iterator;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class GUI extends JPanel {

	private static final long serialVersionUID = 1L;
	private JFrame frame;
	
	private Letter[][] letters;
	
	private boolean running;
	private float marginRatio = 0.2f;
	
	public GUI() {
		frame = new JFrame();
		frame.setSize(1000, 800);
		frame.setTitle("Wordle");
		frame.setVisible(true);
		frame.setLocationRelativeTo(null);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.add(this);

		letters = new Letter[5][6];
		for (int x = 0; x < letters.length; x++) {
			for (int y = 0; y < letters[0].length; y++) {
				letters[x][y] = new Letter();
			}
		}
		
		new Thread(new Runnable() {			
			@Override
			public void run() {
				running = true;
				while (running) {
					repaint();
					try {
						Thread.sleep(16);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			}
		}).start();
	}
	
	@Override
	protected void paintComponent(Graphics g) {
		Graphics2D g2d = (Graphics2D) g;
		
		if (letters == null) {
			return;
		}
		
		g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
		g2d.setFont(new Font(null, Font.BOLD, 48));
		g2d.setStroke(new BasicStroke(4));
		
		int framew = getSize().width;
		int frameh = getSize().height;
		
		g2d.setColor(Color.DARK_GRAY);
		g2d.fillRect(0, 0, framew, frameh);
		
		int letterSize = frameh / 10;
		int margin = (int) (letterSize * marginRatio);
		int offsetX = framew / 2 - (5 * letterSize + 4 * margin) / 2;
		int offsetY = frameh / 2 - (6 * letterSize + 5 * margin) / 2;
		
		for (int x = 0; x < letters.length; x++) {
			for (int y = 0; y < letters[0].length; y++) {
				int posX = offsetX + x * (letterSize + margin);
				int posY = offsetY + y * (letterSize + margin);
				g2d.setColor(letters[x][y].getColor());
				g2d.fillRect(posX, posY, letterSize, letterSize);
				g2d.setColor(Color.BLACK);
				g2d.drawRect(posX, posY, letterSize, letterSize);
				
				String letter = "" + letters[x][y].getLetter();
				int letterWidth = g2d.getFontMetrics().stringWidth(letter);
				
				g2d.drawString(letter, posX + letterSize / 2 - letterWidth / 2, posY + letterSize / 2 + 20);
			}
		}
	}
}