2020. augusztus 23., vasárnap

Fraktál létrehozása python segítségével

 Egyszerű alakzatokból bonyolult alapzatok létrehozása.


WIKI link


---Python minta:

import numpy as np

from PIL import Image

import matplotlib.pyplot as plt


PIXEL_SCALE = 200

WIDTH = 3

HEIGHT = 3

XSTART = -2

YSTART = -1.5


image_width = int(PIXEL_SCALE*WIDTH)

image_height = int(PIXEL_SCALE*HEIGHT)


def create_color(v):

    values = [0, 64, 128, 196]

    b = values[v % 4] 

    g = values[(v//4) % 4] 

    r = values[(v//16) % 4]

    return (r, g, b)



def calc(c1, c2):

    x = y = 0

    for i in range(1000):

        x, y = x*x - y*y + c1, 2*x*y + c2

        if x*x + y*y > 4:

            return i+1

    return 0


array = np.zeros((image_height,

                  image_width,

                  3),

                 dtype=np.uint8)


for i in range(image_width):

    c1 = XSTART + i/PIXEL_SCALE

    for j in range(image_height):

        c2 = YSTART + j/PIXEL_SCALE

        v = calc(c1, c2)

        array[j, i,] = create_color(v)


img = Image.fromarray(array)

# img.save('mandelbrot-colour.png')

plt.imshow(img, cmap='hot')

plt.axis("off")

plt.show()







---Python minta:

import math

from random import randint

from collections import namedtuple

# const - upper limit for randint

s = 20

class Point(namedtuple('Point', 'x y')):

    def __str__(self):

        return'{} {}'.format(self.x, self.y)


    def __add__(self, other):

        assert isinstance(other, Point)

        return Point(self.x + other.x, self.y + other.y)


    def __mul__(self, other):

        return Point(self.x * other, self.y * other)


    def __rmul__(self, other):

        return self.__mul__(other)



class Branch(namedtuple('Branch', 'p1 p2 color size')):


    def __str__(self):

        """Path SVG object with points, color and stroke of branch."""

        return ('<path d="M {p1} L {p2}" '

                'stroke="rgb(100,{c},0)" stroke-width="{w}"/>\n'.

                format(p1=self.p1, p2=self.p2, w=self.size, c=self.color))


    def __repr__(self):

        return self.__str__()



class Tree(object):


    def __init__(self, length, angle, depth, point, size, color, outlist):

        """Main point of start generation."""

        self.branches = outlist

        self.draw_branches(length, angle, depth, point, size, color)


    def draw_branches(self, length, angle, depth, p1, size, color):

        """ Recursively generate three Branch objects per iteration."""

        if depth <= 0:

            return


        p2 = p1 + length * Point(

            math.cos(math.radians(angle)),

            math.sin(math.radians(angle))

        )


        # set some new characteristics for the next level

        branch_length = 2.0 / 3.0 * length

        branch_size = 2.0 / 3.0 * size + 1

        color += 6


        # Calculate new angle and recurse

        self.branches.append(Branch(p1, p2, color, branch_size))

        nangle = angle + randint(-10, s)

        self.draw_branches(branch_length, nangle, depth - 1,

                           p2, branch_size, color)


        # Calculate new angle and recurse

        b = Point(p1.x, p2.y)

        self.branches.append(Branch(p1, b, color, branch_size))

        nangle = angle + randint(-1, 0) * randint(1, s)

        self.draw_branches(branch_length, nangle, depth - 1,

                           b, branch_size, color)


        # Calculate new angle and recurse

        c = Point(-p2.x + 2 * p1.x, p2.y)

        self.branches.append(Branch(p1, c, color, branch_size))

        nangle = angle + randint(0, 1) * randint(1, s)

        self.draw_branches(branch_length, nangle, depth - 1,

                           c, branch_size, color)


    def write_svg(self, output='kl_py_fractral_20.svg'):

        with open(output, 'w') as outfile:

            outfile.write('<svg xmlns="http://www.w3.org/2000/svg" '

                          'viewBox="0 0 800 800" version="1.1">\n')

            outfile.writelines(map(str, self.branches))

            outfile.write('</svg>\n')



resultlist = [Branch(Point(400, 800), Point(400, 600), color=60, size=35)]

t = Tree(length=200, angle=-20, depth=9, point=Point(400, 600), size=35, color=60, outlist=resultlist)

t.write_svg()








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