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#!/usr/bin/env python
# coding=utf-8
#
# Copyright (C) 2005 Carsten Goetze c.goetze@tu-bs.de
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
import math
import random
import inkex
from inkex.paths import Move, Line
def calculate_subdivision(smoothness, x1, y1, x2, y2):
# Calculate the vector from (x1,y1) to (x2,y2)
x3 = x2 - x1
y3 = y2 - y1
# Calculate the point half-way between the two points
hx = x1 + x3 / 2
hy = y1 + y3 / 2
# Calculate normalized vector perpendicular to the vector (x3,y3)
length = math.sqrt(x3 * x3 + y3 * y3)
if length != 0:
nx = -y3 / length
ny = x3 / length
else:
nx = 1
ny = 0
# Scale perpendicular vector by random factor """
r = random.uniform(-length / (1 + smoothness), length / (1 + smoothness))
nx = nx * r
ny = ny * r
# add scaled perpendicular vector to the half-way point to get the final displaced subdivision point
x = hx + nx
y = hy + ny
return (x, y)
class Fractalize(inkex.EffectExtension):
def add_arguments(self, pars):
pars.add_argument(
"-s", "--subdivs", type=int, default=6, help="Number of subdivisons"
)
pars.add_argument(
"-f",
"--smooth",
type=float,
default=4.0,
help="Smoothness of the subdivision",
)
def effect(self):
for node in self.svg.selection.filter(inkex.PathElement):
path = node.path.to_absolute()
result = []
for cmd_proxy in path.proxy_iterator(): # type: inkex.Path.PathCommandProxy
prev = cmd_proxy.previous_end_point
end = cmd_proxy.end_point
if cmd_proxy.letter == "M":
result.append(Move(*cmd_proxy.args))
else:
for seg in self.fractalize(
(prev.x, prev.y, end.x, end.y),
self.options.subdivs,
self.options.smooth,
):
result.append(Line(*seg))
result.append(Line(end.x, end.y))
node.path = result
def fractalize(self, coords, subdivs, smooth):
"""recursively subdivide the segments left and right of the subdivision"""
subdiv_point = calculate_subdivision(smooth, *coords)
if subdivs:
# recursively subdivide the segment left of the subdivision point
for left_seg in self.fractalize(
coords[:2] + subdiv_point[-2:], subdivs - 1, smooth
):
yield left_seg
yield subdiv_point
# recursively subdivide the segment right of the subdivision point
for right_seg in self.fractalize(
subdiv_point[-2:] + coords[-2:], subdivs - 1, smooth
):
yield right_seg
if __name__ == "__main__":
Fractalize().run()
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