Added option to convert-to-dashes before running (resolves #11)

Author: mehtank

sendto_silhouette.inx

@@ -50,6 +50,7 @@ Pressure values of 19 or more make the machine misbehave. Beware.
       <param name="speed" type="int" min="0" max="10" _gui-text="Speed">0</param>
       <param name="pressure" type="int" min="0" max="18" _gui-text="Pressure">0</param>
       <param name="speed_help" type="description">Use speed=0, pressure=0 to take the media defaults.</param>
+      <param name="dashes" type="boolean" _gui-text="Convert to dashes">false</param> <param name="dashes_help" type="description">Convert paths with dashed strokes to separate subpaths for perforated cuts.</param>
       <param name="autocrop" type="boolean" _gui-text="Trim margins">false</param> <param name="autocrop_help" type="description">Shift to the top lefthand corner, then do offsets.</param>
       <param name="bbox_only" type="boolean" _gui-text="Draft Bounding Box Only">false</param>
       <param name="bbox_help" type="description">To see the used area, tick the checkmark above and use pressure=1 (or better remove tool)</param>

sendto_silhouette.py

@@ -119,6 +119,7 @@
 
 from silhouette.Graphtec import SilhouetteCameo
 from silhouette.Strategy import MatFree
+from silhouette.convert2dashes import splitPath
 
 N_PAGE_WIDTH = 3200
 N_PAGE_HEIGHT = 800
@@ -254,6 +255,9 @@ def __init__(self):
 
     self.OptionParser.add_option('--active-tab', action = 'store', dest = 'active_tab',
           help=SUPPRESS_HELP)
+    self.OptionParser.add_option('-d', '--dashes',
+          action = 'store', dest = 'dashes', type = 'inkbool', default = False,
+          help='convert paths with dashed strokes to separate subpaths for perforated cuts')
     self.OptionParser.add_option('-a', '--autocrop',
           action = 'store', dest = 'autocrop', type = 'inkbool', default = False,
           help='trim away top and left margin (before adding offsets)')
@@ -508,6 +512,9 @@ def recursivelyTraverseSvg( self, aNodeList,
 
                         elif node.tag == inkex.addNS( 'path', 'svg' ):
 
+                                if self.options.dashes:
+                                        splitPath(inkex, node)
+
                                 self.pathcount += 1
 
                                 # if we're in resume mode AND self.pathcount < self.svgLastPath,

silhouette/convert2dashes.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python 
+
+# Extracted from inkscape extension; original comments below:
+'''
+This extension converts a path into a dashed line using 'stroke-dasharray'
+It is a modification of the file addnodes.py
+
+Copyright (C) 2005,2007 Aaron Spike, aaron@ekips.org
+Copyright (C) 2009 Alvin Penner, penner@vaxxine.com
+
+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
+'''
+# local library
+import cubicsuperpath
+import bezmisc
+import simplestyle
+
+def tpoint((x1,y1), (x2,y2), t = 0.5):
+    return [x1+t*(x2-x1),y1+t*(y2-y1)]
+def cspbezsplit(sp1, sp2, t = 0.5):
+    m1=tpoint(sp1[1],sp1[2],t)
+    m2=tpoint(sp1[2],sp2[0],t)
+    m3=tpoint(sp2[0],sp2[1],t)
+    m4=tpoint(m1,m2,t)
+    m5=tpoint(m2,m3,t)
+    m=tpoint(m4,m5,t)
+    return [[sp1[0][:],sp1[1][:],m1], [m4,m,m5], [m3,sp2[1][:],sp2[2][:]]]
+def cspbezsplitatlength(sp1, sp2, l = 0.5, tolerance = 0.001):
+    bez = (sp1[1][:],sp1[2][:],sp2[0][:],sp2[1][:])
+    t = bezmisc.beziertatlength(bez, l, tolerance)
+    return cspbezsplit(sp1, sp2, t)
+def cspseglength(sp1,sp2, tolerance = 0.001):
+    bez = (sp1[1][:],sp1[2][:],sp2[0][:],sp2[1][:])
+    return bezmisc.bezierlength(bez, tolerance)    
+
+def splitPath(inkex, node):
+    dashes = []
+    style = simplestyle.parseStyle(node.get('style'))
+    if style.has_key('stroke-dasharray'):
+        if style['stroke-dasharray'].find(',') > 0:
+            dashes = [float (dash) for dash in style['stroke-dasharray'].split(',') if dash]
+    if dashes:
+        p = cubicsuperpath.parsePath(node.get('d'))
+        new = []
+        for sub in p:
+            idash = 0
+            dash = dashes[0]
+            length = 0
+            new.append([sub[0][:]])
+            i = 1
+            while i < len(sub):
+                dash = dash - length
+                length = cspseglength(new[-1][-1], sub[i])
+                while dash < length:
+                    new[-1][-1], next, sub[i] = cspbezsplitatlength(new[-1][-1], sub[i], dash/length)
+                    if idash % 2:           # create a gap
+                        new.append([next[:]])
+                    else:                   # splice the curve
+                        new[-1].append(next[:])
+                    length = length - dash
+                    idash = (idash + 1) % len(dashes)
+                    dash = dashes[idash]
+                if idash % 2:
+                    new.append([sub[i]])
+                else:
+                    new[-1].append(sub[i])
+                i+=1
+        node.set('d',cubicsuperpath.formatPath(new))
+        del style['stroke-dasharray']
+        node.set('style', simplestyle.formatStyle(style))
+        if node.get(inkex.addNS('type','sodipodi')):
+            del node.attrib[inkex.addNS('type', 'sodipodi')]