import media

def get_picture():
    filename = media.choose_file()
    pic = media.load_picture(filename)
    media.show(pic)
    return pic

def make_test_pic():
    '''Return a 48 x 48 test picture with red, black, white and blue pixels.'''

    # n X n sized picture
    n = 48

    # number of columns in each block of color
    block_size = n/4
    
    pic = media.create_picture(n, n)

    for i in range(block_size * 0, block_size * 0 + block_size):        
        for j in range(0,n):
            p = media.get_pixel(pic, i, j)
            media.set_color(p, media.red)

    for i in range(block_size * 1, block_size * 1 + block_size):        
        for j in range(0,n):
            p = media.get_pixel(pic, i, j)
            media.set_color(p, media.black)

    for i in range(block_size * 2, block_size * 2 + block_size):        
        for j in range(0,n):
            p = media.get_pixel(pic, i, j)
            media.set_color(p, media.white)

    for i in range(block_size * 3, block_size * 3 + block_size):        
        for j in range(0,n):
            p = media.get_pixel(pic, i, j)
            media.set_color(p, media.blue)

    return pic

def maximize_red(pic):
    for pix in pic:
        media.set_red(pix, 255)


def reduce_red(pic):
    '''For each pixel in Picture pic, set the red component to zero
    if it is currently greater than 100.'''

    for p in pic:
        if media.get_red(p) > 100:
            media.set_red(p, 0)