''' Recolor images '''

from PIL import Image

import random


def random_color() :
    ''' Returns a random RGB three-tuple '''

    r = random.randrange( 0, 256 )
    g = random.randrange( 0, 256 )
    b = random.randrange( 0, 256 )
    return ( r, g, b )


def get_width( drawing ) :

    ''' Returns the width of the Image represented by drawing. '''

    w, h = drawing.size
    return w



def get_height( drawing ) :

    ''' Returns the height of the Image represented by drawing. '''

    w, h = drawing.size
    return h


def left( spot ) :

    ''' Returns the coordinate immediately left of spot '''

    x, y = spot
    return ( x - 1, y )


def right( spot ) :

    ''' Returns the coordinate immediately right of spot '''

    x, y = spot
    return ( x + 1, y )


def above( spot ) :

    ''' Returns the coordinate immediately above spot '''

    x, y = spot
    return ( x, y - 1 )


def below( spot ) :

    ''' Returns the coordinate immediately below spot '''

    x, y = spot
    return ( x, y + 1 )


def is_inbounds( drawing, spot ) :

    ''' Returns spot is inbounds on drawing. '''

    x, y = spot
    w, h = get_width( drawing ), get_height( drawing )
    
    xgood = ( 0 <= x < w )
    ygood = ( 0 <= y < h )

    return ( xgood and ygood )

def get_color( drawing, spot ) :

    ''' If spot is inbounds on drawing, returns the color at that spot;
        otherwise, None. '''

    if ( is_inbounds( drawing, spot ) ) :
        return drawing.getpixel( spot )
    else :
        return None


def is_colorable( drawing, spot, bg=(255,255,255) ) :

    ''' Returns whether spot is inbounds on drawing and equal to bg '''

    rgb = get_color( drawing, spot )

    return ( rgb == bg ) 


def paint( drawing, spot, c, bg=(255,255,255) ) :

    ''' If spot is a colorable pixel on drawing, the pixel at that spot
        is set to c. '''

    if ( is_colorable( drawing, spot, bg ) ) :
        drawing.putpixel( spot, c )