private class PixelBoard extends JPanel implements MouseListener, MouseMotionListener {
    private boolean leftMouse = false;
    private HiddenOptions hiddenOptions;

public Bucket(int startPixel, Color groupColor) {
        this.groupColor = groupColor;
        if (groupColor != getColor) {
            bucket = add(startPixel, getColor, bucket);
            getPixels.add(startPixel);
        }
        new Thread(this).start();
    }

    @Override
    public void run() {
        while (!getPixels.isEmpty()) {
            getPixels = move(getPixels, groupColor, getColor, bucket);
        }
    }

    public ArrayList<Integer> bucket() {
        return bucket;
    }

    private ArrayList<Integer> add(int p, Color getColor, ArrayList<Integer> bucket) {
        pixel[p].setColor(getColor);
        pixel[p].setToolTipText(pixel(p));
        container.repaint();
        bucket.add(p);
        return bucket;
    }

    private ArrayList<Integer> move(ArrayList<Integer> getPixels, Color groupColor, Color getColor, ArrayList<Integer> bucket) {
        ArrayList<Integer> pix = new ArrayList<Integer>();
        for (int p : getPixels) {
            for (int m : mov(p)) {
                if (!bucket.contains(m)) {
                    if (pixel[m].getColor().equals(groupColor)) {
                        bucket = add(m, getColor, bucket);
                        pix.add(m);
                    }
                }
            }
        }
        return pix;
    }

            private boolean[] pixelLocations(int index) {
    boolean topLeftCorner = index == 0, topRightCorner = index == pixels - 1;
    boolean bottomLeftCorner = index == lastPixel - pixels, bottomRightCorner = index == lastPixel - 1;
    boolean leftEdge = index % pixels == 0, rightEdge = (index + 1) % pixels == 0;
    boolean topEdge = index > 0 && index < pixels - 1, bottomEdge = index > lastPixel - pixels && index < lastPixel - 1;
    return new boolean[] {topLeftCorner, topRightCorner, bottomLeftCorner, bottomRightCorner, leftEdge, rightEdge, topEdge, bottomEdge};
}


    private int[] move(int p) {
        int[] move = {p + 1, p - 1, p + pixels, p - pixels};
        boolean[] location = pixelLocations(p);
        if (location[0])
            move = move(move, new int[] {0, 2});
        else if (location[1])
            move = move(move, new int[] {1, 2});
        else if (location[2])
            move = move(move, new int[] {0, 3});
        else if (location[3])
            move = move(move, new int[] {1, 3});
        else if (location[4])
            move = move(move, new int[] {0, 2, 3});
        else if (location[5])
            move = move(move, new int[] {1, 2, 3});
        else if (location[6])
            move = move(move, new int[] {0, 1, 2});
        else if (location[7])
            move = move(move, new int[] {0, 1, 3});
        return move;
    }

    private int[] move(int[] move, int[] newMove) {
        int[] m = new int[newMove.length];
        for (int i = 0; i < m.length; i++)
            m[i] = move[newMove[i]];
        return m;
    }