recursive_art.py

""""
HEADER COMMENTS:
AUTHOR: EMILY YEH
DESCRIPTION: This program creates art using computation as an artistic medium.
LAST UPDATED: FEBRUARY 19, 2016
ADDITIONAL NOTES: I'm sorry this is late!
"""

from random import *
from PIL import Image
from math import *

bases = [["x"], ["y"]]
functions = ["prod", "avg", "cos_pi", "sin_pi", "squares", "biquadratics"]

def build_random_function(min_depth, max_depth):
    """ Builds a random function of depth at least min_depth and depth
        at most max_depth (see assignment writeup for definition of depth
        in this context)

        min_depth: the minimum depth of the random function
        max_depth: the maximum depth of the random function
        returns: the randomly generated function represented as a nested list
                (see assignment writeup for details on the representation of
                these functions)
    """
    if max_depth == 0:
        return bases[randint(0, 1)]
    if min_depth <= 0:
        return  bases[randint(0, 1)]
    
    functions_index = randint(0, 5)
    if functions_index > 2:
        return [functions[functions_index], build_random_function((min_depth - 1), (max_depth - 1))]
    else:
        return [functions[functions_index], build_random_function((min_depth - 1), (max_depth - 1)), build_random_function((min_depth - 1), (max_depth - 1))]


def evaluate_random_function(f, x, y):
    """ Evaluate the random function f with inputs x,y
        Representation of the function f is defined in the assignment writeup

        f: the function to evaluate
        x: the value of x to be used to evaluate the function
        y: the value of y to be used to evaluate the function
        returns: the function value

        >>> evaluate_random_function(["x"], -0.5, 0.75)
        -0.5
        >>> evaluate_random_function(["y"], 0.1, 0.02)
        0.02
    """
    if len(f) == 1:
        if f == ["x"]:
            return float(x)
        elif f == ["y"]:
            return float(y)

    if f[0] == "prod":
        return evaluate_random_function(f[1], x, y) * evaluate_random_function(f[2], x, y)
    elif f[0] == "avg":
        return (evaluate_random_function(f[1], x, y) + evaluate_random_function(f[2], x, y)) / 2
    elif f[0] == "cos_pi":
        return cos(evaluate_random_function(f[1], x, y) * pi)
    elif f[0] == "sin_pi":
        return sin(evaluate_random_function(f[1], x, y) * pi)
    elif f[0] == "squares":
        return (evaluate_random_function(f[1], x, y)) ** 2
    elif f[0] == "biquadratics":
        return (evaluate_random_function(f[1], x, y)) ** 4


def remap_interval(val,
                   input_interval_start,
                   input_interval_end,
                   output_interval_start,
                   output_interval_end):
    """ Given an input value in the interval [input_interval_start,
        input_interval_end], return an output value scaled to fall within
        the output interval [output_interval_start, output_interval_end].

        val: the value to remap
        input_interval_start: the start of the interval that contains all
                              possible values for val
        input_interval_end: the end of the interval that contains all possible
                            values for val
        output_interval_start: the start of the interval that contains all
                               possible output values
        output_inteval_end: the end of the interval that contains all possible
                            output values
        returns: the value remapped from the input to the output interval

        >>> remap_interval(0.5, 0, 1, 0, 10)
        5.0
        >>> remap_interval(5, 4, 6, 0, 2)
        1.0
        >>> remap_interval(5, 4, 6, 1, 2)
        1.5
    """
    scale = float(val - input_interval_start) / (input_interval_end - input_interval_start)
    scaled_output = (scale * (output_interval_end - output_interval_start)) + output_interval_start
    return scaled_output


def color_map(val):
    """ Maps input value between -1 and 1 to an integer 0-255, suitable for
        use as an RGB color code.

        val: value to remap, must be a float in the interval [-1, 1]
        returns: integer in the interval [0,255]

        >>> color_map(-1.0)
        0
        >>> color_map(1.0)
        255
        >>> color_map(0.0)
        127
        >>> color_map(0.5)
        191
    """
    color_code = remap_interval(val, -1, 1, 0, 255)
    return int(color_code)


# def test_image(filename, x_size=350, y_size=350):
#     """ Generate test image with random pixels and save as an image file.

#         filename: string filename for image (should be .png)
#         x_size, y_size: optional args to set image dimensions (default: 350)
#     """
#     # Create image and loop over all pixels
#     im = Image.new("RGB", (x_size, y_size))
#     pixels = im.load()
#     for i in range(x_size):
#         for j in range(y_size):
#             x = remap_interval(i, 0, x_size, -1, 1)
#             y = remap_interval(j, 0, y_size, -1, 1)
#             pixels[i, j] = (random.randint(0, 255),  # Red channel
#                             random.randint(0, 255),  # Green channel
#                             random.randint(0, 255))  # Blue channel
 
#     im.save(filename)


def generate_art(filename, x_size=350, y_size=350):
    """ Generate computational art and save as an image file.

        filename: string filename for image (should be .png)
        x_size, y_size: optional args to set image dimensions (default: 350)
    """
    # Functions for red, green, and blue channels - where the magic happens!
    red_function = build_random_function(2, 9) #["X"]
    green_function = build_random_function(2, 9) #["Y"]
    blue_function = build_random_function(2, 9) #["X"]

    im = Image.new("RGB", (x_size, y_size))
    pixels = im.load()
    for i in range(x_size):
        for j in range(y_size):
            x = remap_interval(i, 0, x_size, -1, 1)
            y = remap_interval(j, 0, y_size, -1, 1)
            pixels[i, j] = (
                    color_map(evaluate_random_function(red_function, x, y)),
                    color_map(evaluate_random_function(green_function, x, y)),
                    color_map(evaluate_random_function(blue_function, x, y))
                    )

    # im.show(filename)
    im.save(filename)


if __name__ == '__main__':
    import doctest
    doctest.testmod()

generate_art("example3.png")

# print build_random_function(7,9)