crop method
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, which must be in [0,getWidth()) @param top The top coordinate, which must be in [0,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.
Implementation
@override
LuminanceSource crop(int left, int top, int width, int height) {
return RGBLuminanceSource.crop(_luminances, _dataWidth, _dataHeight,
_left + left, _top + top, width, height);
}