public LuminanceSource crop(int left, int top, int width, int height) {
    throw new RuntimeException("This luminance source does not support cropping.");
  }
Returns a new object with cropped image data. Implementations may keep a reference to the
original data rather than a copy. Only callable if isCropSupported() is true.

@param left The left coordinate, 0 <= left < getWidth().
@param top The top coordinate, 0 <= top <= getHeight().
@param width The width of the rectangle to crop.
@param height The height of the rectangle to crop.
@return A cropped version of this object.
OCRTest/src/main/java/edu/sfsu/cs/orange/ocr/LuminanceSource.java