dither.java

public static void ditherToBlackWhite(LightBitmap bitmap)
    {
        double[][] separatedColorArray = new double[bitmap.getWidth()][bitmap.getHeight()];

        for (int y = 0; y < bitmap.getHeight(); y++)
        {
            for (int x = 0; x < bitmap.getWidth(); x++)
            {
                separatedColorArray[x][y] = getGrayscaleColor(bitmap.getPixel(x, y));
            }
        }

        for (int y = 0; y < bitmap.getHeight(); y++)
        {
            for (int x = 0; x < bitmap.getWidth(); x++)
            {
                double oldColor = separatedColorArray[x][y];
                double newColor = getNearestBlackWhiteColor(oldColor);
                bitmap.setPixel(x, y, Color.rgb((int) newColor, (int) newColor, (int) newColor));

                double quantError = oldColor - newColor;

                if (x < bitmap.getWidth() - 1)
                    separatedColorArray[x + 1][y] += quantError * 7.0 / 16;

                if (y < bitmap.getHeight() - 1)
                {
                    if (x > 0)
                        separatedColorArray[x - 1][y + 1] += quantError * 3.0 / 16.0;

                    separatedColorArray[x][y + 1] += quantError * 5.0 / 16.0;

                    if (x < bitmap.getWidth() - 1)
                        separatedColorArray[x + 1][y + 1] += quantError / 16.0;
                }
            }
        }
    }

    public static double getGrayscaleColor(int rgbPixel)
    {
        return Math.round((Color.red(rgbPixel) + Color.green(rgbPixel) + Color.blue(rgbPixel)) / 3.0);
    }

    public static double getNearestBlackWhiteColor(double colorWithError)
    {
        return colorWithError > 255 / 2 ? 255 : 0;
    }