added subroutine ROBO (Master) spline

(bzr r6637)

1 files changed, 70 insertions, 2 deletions

diff --git a/share/extensions/dxf_outlines.py b/share/extensions/dxf_outlines.py
index 10b9f1286..f5f9ce19f 100755
--- a/share/extensions/dxf_outlines.py
+++ b/share/extensions/dxf_outlines.py
@@ -3,7 +3,8 @@
 Copyright (C) 2005,2007,2008 Aaron Spike, aaron@ekips.org
 Copyright (C) 2008 Alvin Penner, penner@vaxxine.com
 
-- template dxf_outlines.dxf added Feb 2008 by Alvin Penner, penner@vaxxine.com
+- template dxf_outlines.dxf added Feb 2008 by Alvin Penner
+- ROBO-Master output option added Aug 2008 by Alvin Penner
 
 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
@@ -19,11 +20,25 @@ 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
 '''
-import inkex, simplepath, cubicsuperpath, dxf_templates
+import inkex, simplepath, cubicsuperpath, dxf_templates, math
+
+try:
+    from numpy import *
+    from numpy.linalg import solve
+except:
+    inkex.errormsg(_("Failed to import the numpy or numpy.linalg modules. These modules are required by this extension. Please install them and try again."))
+    sys.exit()
+
+def pointdistance((x1,y1),(x2,y2)):
+    return math.sqrt(((x2 - x1) ** 2) + ((y2 - y1) ** 2))
+
+def get_fit(u, csp, col):
+    return (1-u)**3*csp[0][col] + 3*(1-u)**2*u*csp[1][col] + 3*(1-u)*u**2*csp[2][col] + u**3*csp[3][col]
 
 class MyEffect(inkex.Effect):
     def __init__(self):
         inkex.Effect.__init__(self)
+        self.OptionParser.add_option("-R", "--ROBO", action="store", type="string", dest="ROBO")
         self.dxf = []
         self.handle = 255                       # initiallize handle for DXF ENTITY
     def output(self):
@@ -43,9 +58,60 @@ class MyEffect(inkex.Effect):
                 self.dxf_add(" 40\n%d\n" % i)
         for i in csp:
             self.dxf_add(" 10\n%f\n 20\n%f\n 30\n0.0\n" % (i[0],i[1]))
+    def ROBO_spline(self,csp):
+        # this spline has zero curvature at the endpoints, as in ROBO-Master
+        knots = 10
+        ctrls = 6
+        fits = 4
+        xfit = zeros((6), dtype=float64)
+        xfit[0] = csp[0][0]
+        xfit[1] = get_fit(.333, csp, 0)
+        xfit[2] = get_fit(.667, csp, 0)
+        xfit[3] = csp[3][0]
+        yfit = zeros((6), dtype=float64)
+        yfit[0] = csp[0][1]
+        yfit[1] = get_fit(.333, csp, 1)
+        yfit[2] = get_fit(.667, csp, 1)
+        yfit[3] = csp[3][1]
+        d1 = pointdistance((xfit[0],yfit[0]),(xfit[1],yfit[1]))
+        d2 = pointdistance((xfit[1],yfit[1]),(xfit[2],yfit[2]))
+        d3 = pointdistance((xfit[2],yfit[2]),(xfit[3],yfit[3]))
+        u1 = d1/(d1 + d2 + d3)
+        u2 = (d1 + d2)/(d1 + d2 + d3)
+        solmatrix = zeros((6,6), dtype=float64)
+        solmatrix[0,0] = 1
+        solmatrix[1,1] = (1 - u1/u2)**2
+        solmatrix[1,2] = (2*u2 - u1*u2 - u1)*u1/u2/u2
+        solmatrix[1,3] = u1*u1/u2
+        solmatrix[2,2] = (1 - u2)**2/(1 - u1)
+        solmatrix[2,3] = (2*u2 - u1*u2 - u1)*(1 - u2)/(1 - u1)/(1 - u1)
+        solmatrix[2,4] = ((u2 - u1)/(1 - u1))**2
+        solmatrix[3,5] = 1
+        solmatrix[4,0] = u2
+        solmatrix[4,1] = -u1 - u2
+        solmatrix[4,2] = u1
+        solmatrix[5,3] = 1 - u2
+        solmatrix[5,4] = u1 + u2 - 2
+        solmatrix[5,5] = 1 - u1
+        xctrl = solve(solmatrix, xfit)
+        yctrl = solve(solmatrix, yfit)
+        self.dxf_add("  0\nSPLINE\n  5\n%x\n100\nAcDbEntity\n  8\n0\n100\nAcDbSpline\n" % self.handle)
+        self.dxf_add(" 70\n0\n 71\n3\n 72\n%d\n 73\n%d\n 74\n%d\n" % (knots, ctrls, fits))
+        for i in range(4):
+            self.dxf_add(" 40\n0\n")
+        self.dxf_add(" 40\n%f\n" % u1)
+        self.dxf_add(" 40\n%f\n" % u2)
+        for i in range(4):
+            self.dxf_add(" 40\n1\n")
+        for i in range(6):
+            self.dxf_add(" 10\n%f\n 20\n%f\n 30\n0.0\n" % (xctrl[i],yctrl[i]))
+        for i in range(4):
+            self.dxf_add(" 11\n%f\n 21\n%f\n 31\n0.0\n" % (xfit[i],yfit[i]))
+
     def effect(self):
         #References:   Minimum Requirements for Creating a DXF File of a 3D Model By Paul Bourke
         #              NURB Curves: A Guide for the Uninitiated By Philip J. Schneider
+        #              The NURBS Book By Les Piegl and Wayne Tiller (Springer, 1995)
         self.dxf_add("999\nDXF created by Inkscape\n")
         self.dxf_add(dxf_templates.r14_header)
 
@@ -66,6 +132,8 @@ class MyEffect(inkex.Effect):
                     e = sub[i+1]
                     if s[1] == s[2] and e[0] == e[1]:
                         self.dxf_line([s[1],e[1]])
+                    elif (self.options.ROBO == 'true'):
+                        self.ROBO_spline([s[1],s[2],e[0],e[1]])
                     else:
                         self.dxf_spline([s[1],s[2],e[0],e[1]])