1 files changed, 105 insertions, 0 deletions
diff --git a/share/extensions/fractalize.py b/share/extensions/fractalize.py
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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()