reworked unwind_paths

extensions/fablabchemnitz/unwind_paths/.gitattributes

@@ -0,0 +1,2 @@
+# Auto detect text files and perform LF normalization
+* text=auto

extensions/fablabchemnitz/unwind_paths/unwind_paths.inx

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
+    <name>Unwind Paths</name>
+    <id>fablabchemnitz.de.unwind_paths</id>
+    <param name="extrude" type="bool" gui-text="Extrude">false</param>
+    <param name="extrude_height" type="float" min="0.000" max="99999.000" precision="3" gui-text="Extrude height">10.000</param>
+    <param name="unit" gui-text="Unit" type="optiongroup" appearance="combo">
+        <option value="mm">mm</option>
+        <option value="cm">cm</option>
+        <option value="m">m</option>
+        <option value="in">in</option>
+        <option value="pt">pt</option>
+        <option value="px">px</option>
+    </param>
+    <effect>
+        <object-type>all</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">unwind_paths.py</command>
+    </script>
+</inkscape-extension>

extensions/fablabchemnitz/unwind_paths/unwind_paths.py

@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+
+"""
+For each selected path element, this extension creates an additional path element
+consisting of horizontal line segments which are the same size as the original
+line segments. Has option to extrude as a band (add height; adds vertical lines and another horizontal path)
+
+ToDo:
+- option to colorize each line segment of the original curve (we need to split and group the original one to do this). We map the colors to the unwinded paths
+- handle combined paths correctly
+- copy style of input paths and only apply new colors
+
+"""
+
+import inkex
+from inkex import bezier
+from lxml import etree
+import math
+
+class UnwindPaths(inkex.EffectExtension):
+    
+    #draw an SVG line segment between the given (raw) points
+    def drawline(self, pathData, name, parent):
+        line_style   = {'stroke':'#000000','stroke-width':'1px','fill':'none'}
+        line_attribs = {'style' : str(inkex.Style(line_style)),
+                    inkex.addNS('label','inkscape') : name,
+                    'd' : pathData}
+        line = etree.SubElement(parent, inkex.addNS('path','svg'), line_attribs )
+        
+    
+    def add_arguments(self, pars):
+        pars.add_argument('--extrude', type=inkex.Boolean, default=False)
+        pars.add_argument('--extrude_height', type=float, default=10.000)
+        pars.add_argument('--unit', default="mm")
+
+    def effect(self):
+        path_num = 0  
+        shifting = self.svg.unittouu(str(self.options.extrude_height) + self.options.unit)
+        
+        for element in self.svg.selection.filter(inkex.PathElement).values(): 
+            elemGroup = self.svg.get_current_layer().add(inkex.Group(id="unwinding-" + element.get('id')))
+
+            #beginning point of the unwind band:
+            bbox = element.bounding_box() #shift the element to the bottom of the element
+            xmin = bbox.left
+            ymax = bbox.bottom
+   
+            for sub in element.path.to_superpath():
+                new = []
+                new.append([sub[0]])
+                i = 1
+                topPathData = "m {:0.6f},{:0.6f} ".format(xmin, ymax)
+                bottomPathData = "m {:0.6f},{:0.6f} ".format(xmin, ymax + shifting)
+                lengths = []
+                while i <= len(sub) - 1:
+                    length = bezier.cspseglength(new[-1][-1], sub[i]) #sub path length
+                    lengths.append(length)
+                    segment = "l {:0.6f},{:0.0f} ".format(length, 0)
+                    topPathData += segment
+                    bottomPathData += segment
+                    new[-1].append(sub[i])
+                    i += 1           
+                                     
+                self.drawline(topPathData, "hline-top-{0}".format(element.get('id')), elemGroup)
+                if self.options.extrude is True:
+                    self.drawline(bottomPathData, "hline-bottom-{0}".format(element.get('id')), elemGroup)
+                    
+                    #draw as much vertical lines as segments in bezier + start + end vertical line
+                    self.drawline("m {:0.6f},{:0.6f} v {:0.6f}".format(xmin, ymax, shifting),"vline{0}".format(path_num), elemGroup)
+                    self.drawline("m {:0.6f},{:0.6f} v {:0.6f}".format(xmin + sum([length for length in lengths]), ymax, shifting),"vline{0}".format(path_num), elemGroup)
+                    x = 0
+                    for n in range(0, i-1):           
+                        x += lengths[n]
+                        self.drawline("m {:0.6f},{:0.6f} v {:0.6f}".format(xmin + x, ymax, shifting),"vline{0}".format(path_num), elemGroup)
+
+if __name__ == '__main__':
+    UnwindPaths().run()