DotsAndBoxesUI.java

package dotsandboxes;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.MouseInputAdapter;
import java.util.ArrayList;

public class DotsAndBoxesUI {

    static final int lineLength = 32;
    static final int margin = 10;
    static final int gap = 0;
    static final int dotDiameter = 6;

    // The coordinate of the top or left of a the painting area for this row/col
    private static int corner(int col) {
        return margin + col * (gap + lineLength + gap + dotDiameter);
    }

    /** Colours for the different players. Only goes up to 5. */
    static final Color[] playerColours = { Color.WHITE, Color.RED, Color.BLUE, Color.GREEN, Color.PINK, Color.ORANGE };

    final DotsAndBoxesGrid grid;
    final JPanel anchorPane;
    final Canvas canvas;
    final JLabel label;

    private void updateLabel() {
        label.setForeground(playerColours[grid.getPlayer()]);
        label.setText(String.format("Player %d's turn", grid.getPlayer()));
    }

    public DotsAndBoxesUI(final DotsAndBoxesGrid grid) {
        this.grid = grid;
        anchorPane = new JPanel(new BorderLayout());

        label = new JLabel("");
        updateLabel();

        canvas = new DABCanvas();

        anchorPane.add(canvas, BorderLayout.CENTER);
        anchorPane.add(label, BorderLayout.NORTH);

        grid.addConsumer((g) -> {
            updateLabel();
            canvas.repaint();
        });
    }

    /** A component that paints and handles clicks on the game */
    class DABCanvas extends Canvas {

        final ArrayList<Horizontal> horizontals = new ArrayList<>();
        final ArrayList<Vertical> verticals = new ArrayList<>();
        final ArrayList<Box> boxes = new ArrayList<>();

        /** Represents a horizontal line. */
        record Horizontal(int col, int row) {
            Rectangle rect() {
                int x = corner(col) + dotDiameter + gap;
                int y = corner(row);
                return new Rectangle(x, y, lineLength, dotDiameter);
            }

            /** Whether or not this line contains this point */
            boolean contains(int x, int y) {
                return rect().contains(x, y);
            }