import java.awt.Color;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JOptionPane;

public class Test {

    public static void main(String[] args) throws IOException {
        BufferedImage img = ImageIO.read(new File("/Users/swhitehead/Downloads/47hb1.png"));
        Rectangle bounds = getBounds(img, Color.WHITE);
        System.out.println(bounds);
        BufferedImage trimmed = img.getSubimage(bounds.x, bounds.y, bounds.width, bounds.height);
        JOptionPane.showMessageDialog(null, new JLabel(new ImageIcon(trimmed)));
    }

    public static Rectangle getBounds(BufferedImage img, Color fillColor) {
        int top = getYInset(img, 20, 0, 1, fillColor);
        int bottom = getYInset(img, 20, img.getHeight() - 1, -1, fillColor);
        int left = getXInset(img, 0, top, 1, fillColor);
        int right = getXInset(img, img.getWidth() - 1, top, -1, fillColor);

        return new Rectangle(left, top, right - left, bottom - top);
    }

    public static int getYInset(BufferedImage img, int x, int y, int step, Color fillColor) {
        while (new Color(img.getRGB(x, y), true).equals(fillColor)) {
            y += step;
        }
        return y;
    }

    public static int getXInset(BufferedImage img, int x, int y, int step, Color fillColor) {
        while (new Color(img.getRGB(x, y), true).equals(fillColor)) {
            x += step;
        }
        return x;
    }
}

import static marvin.MarvinPluginCollection.*;
import java.awt.Rectangle;
import marvin.image.MarvinImage;
import marvin.io.MarvinImageIO;

public class BoardSegmentation {

    public BoardSegmentation() {
        MarvinImage imageOriginal = MarvinImageIO.loadImage("./res/board.png");
        MarvinImage image = imageOriginal.clone();
        thresholding(image, 250);
        Rectangle rect = getBoundingBox(image);
        crop(imageOriginal, image, rect.x, rect.y, rect.width, rect.height);
        MarvinImageIO.saveImage(image, "./res/board_cropped.png");
    }
    public Rectangle getBoundingBox(MarvinImage image) {
        Rectangle r = new Rectangle();
        r.x = -1; r.y = -1; r.width = -1; r.height = -1;
        for(int y=0; y<image.getHeight(); y++) {
            for(int x=0; x<image.getWidth(); x++) {
                if(image.getIntColor(x, y) == 0xFF000000) {
                    if(r.x == -1 || x < r.x) {  r.x = x;    }
                    if(r.width == -1 || x > r.x + r.width) {    r.width = x - r.x;  }
                    if(r.y == -1 || x < r.y) {  r.y = y;    }
                    if(r.height == -1 || y > r.y + r.height) {  r.height = y - r.y; }
                }
            }
        }
        return r;
    }
    public static void main(String[] args) {
        new BoardSegmentation();
    }
}