#------- CHECKING DEPENDENCIES ----------------------------------------- 
painting_possible = True
try:
    from skimage.filter import sobel
except:
    try:
        from scipy.ndimage.filters import sobel
    except:
        painting_possible = False
#-----------------------------------------------------------------------    



import numpy as np


def to_painting(image,saturation = 1.4,black = 0.006):
    """ transforms any photo into some kind of painting """
    edges = sobel(image.mean(axis=2))
    darkening =  black*(255*np.dstack(3*[edges]))
    painting = saturation*image-darkening
    return np.maximum(0,np.minimum(255,painting)).astype('uint8')
    
def painting(clip, saturation = 1.4,black = 0.006):
    """
    Transforms any photo into some kind of painting. Saturation
    tells at which point the colors of the result should be
    flashy. ``black`` gives the anount of black lines wanted.
    Requires Scikit-image or Scipy installed.
    """
    return clip.fl_image(lambda im : to_painting(im,saturation,black))
        


#------- OVERWRITE IF REQUIREMENTS NOT MET -----------------------------

if not painting_possible:
    doc = painting.__doc__
    def painting(clip, newsize=None, height=None, width=None):
        raise IOError("fx painting needs scikit-image or scipy")
    
    painting.__doc__ = doc
#-----------------------------------------------------------------------