''' Purpose: provide means of reducing the color palette of an image
'''

from PIL import Image

def shrink( original, p ) :
    ''' returns a new_image image where colors from the original are replaced
        with their closest palette correspondents of color palette p
    '''
    ow, oh = original.size
    nw, nh = ow, oh
   
    new_image = Image.new( 'RGB', ( nw, nh ) )

    for nx in range( 0, nw ) :
        for ny in range( 0, nh ) :
            nspot = ( nx, ny )
            ospot = ( nx, ny )

            opixel = original.getpixel( ospot )

            npixel = closest( opixel, p )

            new_image.putpixel( nspot, npixel )

    return new_image

def closest( pixel, p ) :
    ''' Returns the color in palette p closest to pixel
    '''

    pass


def distance( c1, c2 ) :
    ''' returns the distance between c1 and c2
    '''
    pass

def generate_random_palette( n ) :
    # generate a palette p of n random colors

    import random

    p = []

    for i in range( 0, n ) :
        pass

    return p

if ( __name__ == '__main__') :

    import url
    import palette

    # define our palettes
    B        = [ (0,0,0) ]
    BW       = B + [ (255,255,255) ]
    BWRGB    = BW + [ (0,255,0), (0,0,255), (255,0,0) ]
    BWRGBMCY = BWRGB + [ (255,255,0), (255,0,255), (0,255,255) ]
    rand_palette = palette.generate_random_palette( 12 )

    palettes = [ B, BW, BWRGB, BWRGBMCY, rand_palette ]

    location = input( 'Enter image location: ' )

    original = url.get_image( location )

    for p in palettes :

        im = palette.shrink( original, p )

        im.show()