refactored file structures to match extension ids, file names and class names

extensions/fablabchemnitz/zigzag_nodes/zigzag_nodes.inx

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
+    <name>Zigzag Nodes</name>
+    <id>fablabchemnitz.de.zigzag_nodes</id>
+    <label>This effect shifts the nodes of the selected path alternately.</label>
+    <param name="radius" type="float" min="0.0" max="1000.0" gui-text="Maximum displacement, px">3.0</param>
+    <effect>
+        <object-type>path</object-type>
+        <effects-menu>
+            <submenu name="FabLab Chemnitz">
+                <submenu name="Shape/Pattern from existing Path(s)"/>
+            </submenu>
+        </effects-menu>
+    </effect>
+    <script>
+        <command location="inx" interpreter="python">zigzag_nodes.py</command>
+    </script>
+</inkscape-extension>

extensions/fablabchemnitz/zigzag_nodes/zigzag_nodes.py

@@ -0,0 +1,85 @@
+#!/usr/bin/env python3
+'''
+zigzag.py
+Sunabe kazumichi 2009/9/29
+http://dp48069596.lolipop.jp/
+
+
+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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+this program shifts the nodes zigzags.
+'''
+import random
+import math
+import inkex
+from inkex import CubicSuperPath
+
+def pointdistance(x1, y1, x2, y2):
+    dist=math.sqrt(((x2 - x1) ** 2) + ((y2 - y1) ** 2))
+    if dist==0:
+        dx=0
+        dy=0
+    else:
+        dx=(x2 - x1)/dist
+        dy=(y2 - y1)/dist    
+    return dx,dy
+
+def randomize(x,y, r):    
+    if y == 0:
+        a = math.pi
+    elif x == 0 and y != 0:
+        a = math.pi/2
+    else:
+        a = math.atan2(y,x)
+    x = math.cos(a-math.pi/2)*r
+    y = math.sin(a-math.pi/2)*r       
+    return [x, y]
+
+class ZigzagNodes(inkex.EffectExtension):
+    
+    def add_arguments(self, pars):
+        pars.add_argument("--title")
+        pars.add_argument("--radius", type=float,  default=10.0, help="Randomly move control and end points in this radius")
+        
+    def effect(self):
+        for id, node in self.svg.selected.items():
+            if node.tag == inkex.addNS('path','svg'):
+                d = node.get('d')
+                p = CubicSuperPath(d)
+                for subpath in p:
+                    for i, csp in enumerate(subpath):
+                        if i % 2 != 0:
+                            dx,dy=pointdistance(csp[0][0],csp[0][1],csp[1][0],csp[1][1])
+                            delta=randomize(dx, dy, self.options.radius)
+                            csp[0][0]+=delta[0] 
+                            csp[0][1]+=delta[1] 
+                            csp[1][0]+=delta[0] 
+                            csp[1][1]+=delta[1] 
+                            csp[2][0]+=delta[0] 
+                            csp[2][1]+=delta[1]                                
+                        else:
+                            dx,dy=pointdistance(csp[0][0],csp[0][1],csp[1][0],csp[1][1])
+                            delta=randomize(dx, dy, self.options.radius)
+                            csp[0][0]-=delta[0] 
+                            csp[0][1]-=delta[1] 
+                            csp[1][0]-=delta[0] 
+                            csp[1][1]-=delta[1] 
+                            csp[2][0]-=delta[0] 
+                            csp[2][1]-=delta[1]
+
+                node.set('d',CubicSuperPath(p))
+
+if __name__ == '__main__':       
+    ZigzagNodes().run()