paths2openscad.py

#!/usr/bin/env python

# openscad.py

# This is an Inkscape extension to output paths to extruded OpenSCAD polygons
# The Inkscape objects must first be converted to paths (Path > Object to
# Path). Some paths may not work well -- the paths have to be polygons.  As
# such, paths derived from text may meet with mixed results.

# Written by Daniel C. Newman ( dan dot newman at mtbaldy dot us )
# 10 June 2012

# 15 June 2012
#   Updated by Dan Newman to handle a single level of polygon nesting.
#   This is sufficient to handle most fonts.
#   If you want to nest two polygons, combine them into a single path
#   within Inkscape with "Path > Combine Path".

# 15 August 2014
#   Updated by Josef Skladanka to automatically set extruded heights

# 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

import os.path
import inkex
import simplepath
import simpletransform
import cubicsuperpath
import cspsubdiv
import bezmisc
import re
import string

DEFAULT_WIDTH = 100
DEFAULT_HEIGHT = 100
RE_AUTO_HEIGHT = re.compile(r".*?_(\d+(?:_\d+)?)_mm$")


def parseLengthWithUnits(str):
    '''
    Parse an SVG value which may or may not have units attached
    This version is greatly simplified in that it only allows: no units,
    units of px, and units of %.  Everything else, it returns None for.
    There is a more general routine to consider in scour.py if more
    generality is ever needed.
    '''

    u = 'px'
    s = str.strip()
    if s[-2:] == 'px':
        s = s[:-2]
    elif s[-1:] == '%':
        u = '%'
        s = s[:-1]

    try:
        v = float(s)
    except:
        return None, None

    return v, u


def pointInBBox(pt, bbox):
    '''
    Determine if the point pt=[x, y] lies on or within the bounding
    box bbox=[xmin, xmax, ymin, ymax].
    '''

    # if ( x < xmin ) or ( x > xmax ) or ( y < ymin ) or ( y > ymax )
    if (pt[0] < bbox[0]) or (pt[0] > bbox[1]) or \
            (pt[1] < bbox[2]) or (pt[1] > bbox[3]):
        return False
    else:
        return True


def bboxInBBox(bbox1, bbox2):
    '''
    Determine if the bounding box bbox1 lies on or within the
    bounding box bbox2.  NOTE: we do not test for strict enclosure.

    Structure of the bounding boxes is

    bbox1 = [ xmin1, xmax1, ymin1, ymax1 ]
    bbox2 = [ xmin2, xmax2, ymin2, ymax2 ]
    '''

    # if ( xmin1 < xmin2 ) or ( xmax1 > xmax2 ) or
    # ( ymin1 < ymin2 ) or ( ymax1 > ymax2 )

    if (bbox1[0] < bbox2[0]) or (bbox1[1] > bbox2[1]) or \
            (bbox1[2] < bbox2[2]) or (bbox1[3] > bbox2[3]):
        return False
    else:
        return True


def pointInPoly(p, poly, bbox=None):
    '''
    Use a ray casting algorithm to see if the point p = [x, y] lies within
    the polygon poly = [[x1,y1],[x2,y2],...].  Returns True if the point
    is within poly, lies on an edge of poly, or is a vertex of poly.
    '''

    if (p is None) or (poly is None):
        return False

    # Check to see if the point lies outside the polygon's bounding box
    if bbox is not None:
        if not pointInBBox(p, bbox):
            return False

    # Check to see if the point is a vertex
    if p in poly:
        return True

    # Handle a boundary case associated with the point
    # lying on a horizontal edge of the polygon
    x = p[0]
    y = p[1]
    p1 = poly[0]
    p2 = poly[1]
    for i in range(len(poly)):
        if i != 0:
            p1 = poly[i - 1]
            p2 = poly[i]
        if (y == p1[1]) and (p1[1] == p2[1]) and \
                (x > min(p1[0], p2[0])) and (x < max(p1[0], p2[0])):
            return True

    n = len(poly)
    inside = False

    p1_x, p1_y = poly[0]
    for i in range(n + 1):
        p2_x, p2_y = poly[i % n]
        if y > min(p1_y, p2_y):
            if y <= max(p1_y, p2_y):
                if x <= max(p1_x, p2_x):
                    if p1_y != p2_y:
                        intersect = p1_x + (y - p1_y) * (p2_x - p1_x) / \
                                           (p2_y - p1_y)
                        if x <= intersect:
                            inside = not inside
                    else:
                        inside = not inside
        p1_x, p1_y = p2_x, p2_y

    return inside


def polyInPoly(poly1, bbox1, poly2, bbox2):
    '''
    Determine if polygon poly2 = [[x1,y1],[x2,y2],...]
    contains polygon poly1.

    The bounding box information, bbox=[xmin, xmax, ymin, ymax]
    is optional.  When supplied it can be used to perform rejections.
    Note that one bounding box containing another is not sufficient
    to imply that one polygon contains another.  It's necessary, but
    not sufficient.
    '''

    # See if poly1's bboundin box is NOT contained by poly2's bounding box
    # if it isn't, then poly1 cannot be contained by poly2.

    if (bbox1 is not None) and (bbox2 is not None):
        if not bboxInBBox(bbox1, bbox2):
            return False

    # To see if poly1 is contained by poly2, we need to ensure that each
    # vertex of poly1 lies on or within poly2

    for p in poly1:
        if not pointInPoly(p, poly2, bbox2):
            return False

    # Looks like poly1 is contained on or in Poly2

    return True


def subdivideCubicPath(sp, flat, i=1):
    '''
    [ Lifted from eggbot.py with impunity ]

    Break up a bezier curve into smaller curves, each of which
    is approximately a straight line within a given tolerance
    (the "smoothness" defined by [flat]).

    This is a modified version of cspsubdiv.cspsubdiv(): rewritten
    because recursion-depth errors on complicated line segments
    could occur with cspsubdiv.cspsubdiv().
    '''

    while True:
        while True:
            if i >= len(sp):
                return

            p0 = sp[i - 1][1]
            p1 = sp[i - 1][2]
            p2 = sp[i][0]
            p3 = sp[i][1]

            b = (p0, p1, p2, p3)

            if cspsubdiv.maxdist(b) > flat:
                break

            i += 1

        one, two = bezmisc.beziersplitatt(b, 0.5)
        sp[i - 1][2] = one[1]
        sp[i][0] = two[2]
        p = [one[2], one[3], two[1]]
        sp[i:1] = [p]


class OpenSCAD(inkex.Effect):
    def __init__(self):

        inkex.Effect.__init__(self)

        self.OptionParser.add_option(
            "--tab",  # NOTE: value is not used.
            action="store", type="string", dest="tab", default="splash",
            help="The active tab when Apply was pressed")

        self.OptionParser.add_option(
            '--smoothness', dest='smoothness', type='float',
            default=float(0.2), action='store',
            help='Curve smoothing (less for more)')

        self.OptionParser.add_option(
            '--height', dest='height', type='string', default='5',
            action='store', help='Height (mm)')

        self.OptionParser.add_option(
            '--fname', dest='fname', type='string', default='~/inkscape.scad',
            action='store', help='Curve smoothing (less for more)')

        self.OptionParser.add_option(
            '--autoheight', dest='autoheight', type='string', default='false',
            action='store', help='Set heights automatically')

        self.cx = float(DEFAULT_WIDTH) / 2.0
        self.cy = float(DEFAULT_HEIGHT) / 2.0
        self.xmin, self.xmax = (1.0E70, -1.0E70)
        self.ymin, self.ymax = (1.0E70, -1.0E70)

        # Dictionary of paths we will construct.  It's keyed by the SVG node
        # it came from.  Such keying isn't too useful in this specific case,
        # but it can be useful in other applications when you actually want
        # to go back and update the SVG document
        self.paths = {}

        # Output file handling
        self.call_list = []
        self.pathid = int(0)

        # Output file
        self.f = None

        # For handling an SVG viewbox attribute, we will need to know the
        # values of the document's <svg> width and height attributes as well
        # as establishing a transform from the viewbox to the display.

        self.docWidth = float(DEFAULT_WIDTH)
        self.docHeight = float(DEFAULT_HEIGHT)
        self.docTransform = [[1.0, 0.0, 0.0], [0.0, 1.0, 0.0]]

        # Dictionary of warnings issued.  This to prevent from warning
        # multiple times about the same problem
        self.warnings = {}

    def getLength(self, name, default):

        '''
        Get the <svg> attribute with name "name" and default value "default"
        Parse the attribute into a value and associated units.  Then, accept
        units of cm, ft, in, m, mm, pc, or pt.  Convert to pixels.

        Note that SVG defines 90 px = 1 in = 25.4 mm.
        '''

        str = self.document.getroot().get(name)
        if str:
            v, u = parseLengthWithUnits(str)
            if not v:
                # Couldn't parse the value
                return None
            elif (u == 'mm'):
                return float(v) * (90.0 / 25.4)
            elif (u == 'cm'):
                return float(v) * (90.0 * 10.0 / 25.4)
            elif (u == 'm'):
                return float(v) * (90.0 * 1000.0 / 25.4)
            elif (u == 'in'):
                return float(v) * 90.0
            elif (u == 'ft'):
                return float(v) * 12.0 * 90.0
            elif (u == 'pt'):
                # Use modern "Postscript" points of 72 pt = 1 in instead
                # of the traditional 72.27 pt = 1 in
                return float(v) * (90.0 / 72.0)
            elif (u == 'pc'):
                return float(v) * (90.0 / 6.0)
            elif (u == 'px'):
                return float(v)
            else:
                # Unsupported units
                return None
        else:
            # No width specified; assume the default value
            return float(default)

    def getDocProps(self):

        '''
        Get the document's height and width attributes from the <svg> tag.
        Use a default value in case the property is not present or is
        expressed in units of percentages.
        '''

        self.docHeight = self.getLength('height', DEFAULT_HEIGHT)
        self.docWidth = self.getLength('width', DEFAULT_WIDTH)
        if (self.docHeight is None) or (self.docWidth is None):
            return False
        else:
            return True

    def handleViewBox(self):

        '''
        Set up the document-wide transform in the event that the document has
        an SVG viewbox
        '''

        if self.getDocProps():
            viewbox = self.document.getroot().get('viewBox')
            if viewbox:
                vinfo = viewbox.strip().replace(',', ' ').split(' ')
                if (vinfo[2] != 0) and (vinfo[3] != 0):
                    sx = self.docWidth / float(vinfo[2])
                    sy = self.docHeight / float(vinfo[3])
                    self.docTransform = simpletransform.parseTransform(
                        'scale(%f,%f)' % (sx, sy))

    def getPathVertices(self, path, node=None, transform=None):

        '''
        Decompose the path data from an SVG element into individual
        subpaths, each subpath consisting of absolute move to and line
        to coordinates.  Place these coordinates into a list of polygon
        vertices.
        '''

        if (not path) or (len(path) == 0):
            # Nothing to do
            return None

        # parsePath() may raise an exception.  This is okay
        sp = simplepath.parsePath(path)
        if (not sp) or (len(sp) == 0):
            # Path must have been devoid of any real content
            return None

        # Get a cubic super path
        p = cubicsuperpath.CubicSuperPath(sp)
        if (not p) or (len(p) == 0):
            # Probably never happens, but...
            return None

        if transform:
            simpletransform.applyTransformToPath(transform, p)

        # Now traverse the cubic super path
        subpath_list = []
        subpath_vertices = []

        for sp in p:

            # We've started a new subpath
            # See if there is a prior subpath and whether we should keep it
            if len(subpath_vertices):
                subpath_list.append(
                    [subpath_vertices, [sp_xmin, sp_xmax, sp_ymin, sp_ymax]])

            subpath_vertices = []
            subdivideCubicPath(sp, float(self.options.smoothness))

            # Note the first point of the subpath
            first_point = sp[0][1]
            subpath_vertices.append(first_point)
            sp_xmin = first_point[0]
            sp_xmax = first_point[0]
            sp_ymin = first_point[1]
            sp_ymax = first_point[1]

            # See if the first and last points are identical
            # OpenSCAD doesn't mind if we duplicate the first and last
            # vertex, but our polygon in polygon algorithm may
            n = len(sp)
            last_point = sp[n - 1][1]
            if first_point[0] == last_point[0] and \
                    first_point[1] == last_point[1]:
                n = n - 1

            # Traverse each point of the subpath
            for csp in sp[1:n]:

                # Append the vertex to our list of vertices
                pt = csp[1]
                subpath_vertices.append(pt)

                # Track the bounding box of this subpath
                if pt[0] < sp_xmin:
                    sp_xmin = pt[0]
                elif pt[0] > sp_xmax:
                    sp_xmax = pt[0]
                if pt[1] < sp_ymin:
                    sp_ymin = pt[1]
                elif pt[1] > sp_ymax:
                    sp_ymax = pt[1]

            # Track the bounding box of the overall drawing
            # This is used for centering the polygons in OpenSCAD around the
            # (x,y) origin
            if sp_xmin < self.xmin:
                self.xmin = sp_xmin
            if sp_xmax > self.xmax:
                self.xmax = sp_xmax
            if sp_ymin < self.ymin:
                self.ymin = sp_ymin
            if sp_ymax > self.ymax:
                self.ymax = sp_ymax

        # Handle the final subpath
        if len(subpath_vertices):
            subpath_list.append(
                [subpath_vertices, [sp_xmin, sp_xmax, sp_ymin, sp_ymax]])

        if len(subpath_list) > 0:
            self.paths[node] = subpath_list

    def convertPath(self, node):

        path = self.paths[node]
        if (path is None) or (len(path) == 0):
            return

        # Determine which polys contain which

        contains = [[] for i in xrange(len(path))]
        contained_by = [[] for i in xrange(len(path))]

        for i in range(0, len(path)):
            for j in range(i + 1, len(path)):
                if polyInPoly(path[j][0], path[j][1], path[i][0], path[i][1]):
                    # subpath i contains subpath j
                    contains[i].append(j)
                    # subpath j is contained in subpath i
                    contained_by[j].append(i)
                elif polyInPoly(
                        path[i][0], path[i][1], path[j][0], path[j][1]):
                    # subpath j contains subpath i
                    contains[j].append(i)
                    # subpath i is containd in subpath j
                    contained_by[i].append(j)

        # Generate an OpenSCAD module for this path
        id = node.get('id', '')
        if (id is None) or (id == ''):
            id = str(self.pathid) + 'x'
            self.pathid += 1
        else:
            id = re.sub('[^A-Za-z0-9_]+', '', id)
        self.f.write('module poly_' + id + '(h)\n{\n')
        self.f.write('  scale([25.4/90, -25.4/90, 1]) union()\n  {\n')

        # And add the call to the call list
        # Height is set by the overall module parameter
        # unless an auto-height is found.
        height = 'h'
        if self.options.autoheight == 'true':
            found_height = RE_AUTO_HEIGHT.findall(id)
            try:
                height = found_height[-1].replace("_", ".")
            except IndexError:
                pass

        self.call_list.append('poly_%s(%s);\n' % (id, height))

        for i in range(0, len(path)):

            # Skip this subpath if it is contained by another one
            if len(contained_by[i]) != 0:
                continue

            subpath = path[i][0]
            bbox = path[i][1]

            if len(contains[i]) == 0:

                # This subpath does not contain any subpaths
                poly = \
                    '    linear_extrude(height=h)\n' + \
                    '      polygon(['

                for point in subpath:
                    poly += '[%f,%f],' % (
                        (point[0] - self.cx), (point[1] - self.cy))

                poly = poly[:-1]
                poly += ']);\n'
                self.f.write(poly)

            else:

                # This subpath contains other subpaths
                poly = \
                    '    difference()\n' + \
                    '    {\n' + \
                    '       linear_extrude(height=h)\n' + \
                    '         polygon(['

                for point in subpath:
                    poly += '[%f,%f],' % (
                        (point[0] - self.cx), (point[1] - self.cy))

                poly = poly[:-1]
                poly += ']);\n'
                self.f.write(poly)

                for j in contains[i]:

                    poly = \
                        '       translate([0, 0, -fudge])\n' + \
                        '         linear_extrude(height=h+2*fudge)\n' + \
                        '           polygon(['

                    for point in path[j][0]:
                        poly += '[%f,%f],' % (
                            (point[0] - self.cx), (point[1] - self.cy))

                    poly = poly[:-1]
                    poly += ']);\n'
                    self.f.write(poly)

                self.f.write('    }\n')

        # End the module
        self.f.write('  }\n}\n')

    def recursivelyTraverseSvg(self, aNodeList,
                               matCurrent=[[1.0, 0.0, 0.0], [0.0, 1.0, 0.0]],
                               parent_visibility='visible'):

        '''
        [ This too is largely lifted from eggbot.py ]

        Recursively walk the SVG document, building polygon vertex lists
        for each graphical element we support.

        Rendered SVG elements:
            <circle>, <ellipse>, <line>, <path>, <polygon>, <polyline>, <rect>

        Supported SVG elements:
            <group>, <use>

        Ignored SVG elements:
            <defs>, <eggbot>, <metadata>, <namedview>, <pattern>,
            processing directives

        All other SVG elements trigger an error (including <text>)
        '''

        for node in aNodeList:

            # Ignore invisible nodes
            v = node.get('visibility', parent_visibility)
            if v == 'inherit':
                v = parent_visibility
            if v == 'hidden' or v == 'collapse':
                pass

            # First apply the current matrix transform to this node's tranform
            matNew = simpletransform.composeTransform(
                matCurrent,
                simpletransform.parseTransform(node.get("transform")))

            if node.tag == inkex.addNS('g', 'svg') or node.tag == 'g':

                self.recursivelyTraverseSvg(node, matNew, v)

            elif node.tag == inkex.addNS('use', 'svg') or node.tag == 'use':

                # A <use> element refers to another SVG element via an
                # xlink:href="#blah" attribute.  We will handle the element by
                # doing an XPath search through the document, looking for the
                # element with the matching id="blah" attribute.  We then
                # recursively process that element after applying any necessary
                # (x,y) translation.
                #
                # Notes:
                #  1. We ignore the height and width attributes as they do not
                #     apply to path-like elements, and
                #  2. Even if the use element has visibility="hidden", SVG
                #     still calls for processing the referenced element.  The
                #     referenced element is hidden only if its visibility is
                #     "inherit" or "hidden".

                refid = node.get(inkex.addNS('href', 'xlink'))
                if not refid:
                    pass

                # [1:] to ignore leading '#' in reference
                path = '//*[@id="%s"]' % refid[1:]
                refnode = node.xpath(path)
                if refnode:
                    x = float(node.get('x', '0'))
                    y = float(node.get('y', '0'))
                    # Note: the transform has already been applied
                    if (x != 0) or (y != 0):
                        matNew2 = composeTransform(
                            matNew,
                            parseTransform('translate(%f,%f)' % (x, y)))
                    else:
                        matNew2 = matNew
                    v = node.get('visibility', v)
                    self.recursivelyTraverseSvg(refnode, matNew2, v)

            elif node.tag == inkex.addNS('path', 'svg'):

                path_data = node.get('d')
                if path_data:
                    self.getPathVertices(path_data, node, matNew)

            elif node.tag == inkex.addNS('rect', 'svg') or node.tag == 'rect':

                # Manually transform
                #
                #    <rect x="X" y="Y" width="W" height="H"/>
                #
                # into
                #
                #    <path d="MX,Y lW,0 l0,H l-W,0 z"/>
                #
                # I.e., explicitly draw three sides of the rectangle and the
                # fourth side implicitly

                # Create a path with the outline of the rectangle
                x = float(node.get('x'))
                y = float(node.get('y'))
                if (not x) or (not y):
                    pass
                w = float(node.get('width', '0'))
                h = float(node.get('height', '0'))
                a = []
                a.append(['M ', [x, y]])
                a.append([' l ', [w, 0]])
                a.append([' l ', [0, h]])
                a.append([' l ', [-w, 0]])
                a.append([' Z', []])
                self.getPathVertices(simplepath.formatPath(a), node, matNew)

            elif node.tag == inkex.addNS('line', 'svg') or node.tag == 'line':

                # Convert
                #
                #   <line x1="X1" y1="Y1" x2="X2" y2="Y2/>
                #
                # to
                #
                #   <path d="MX1,Y1 LX2,Y2"/>

                x1 = float(node.get('x1'))
                y1 = float(node.get('y1'))
                x2 = float(node.get('x2'))
                y2 = float(node.get('y2'))
                if (not x1) or (not y1) or (not x2) or (not y2):
                    pass
                a = []
                a.append(['M ', [x1, y1]])
                a.append([' L ', [x2, y2]])
                self.getPathVertices(simplepath.formatPath(a), node, matNew)

            elif node.tag == inkex.addNS('polyline', 'svg') or \
                    node.tag == 'polyline':

                # Convert
                #
                #  <polyline points="x1,y1 x2,y2 x3,y3 [...]"/>
                #
                # to
                #
                #   <path d="Mx1,y1 Lx2,y2 Lx3,y3 [...]"/>
                #
                # Note: we ignore polylines with no points

                pl = node.get('points', '').strip()
                if pl == '':
                    pass

                pa = pl.split()
                d = "".join(
                    ["M " + pa[i] if i == 0 else " L " + pa[i] for i in range(
                        0, len(pa))])
                self.getPathVertices(d, node, matNew)

            elif node.tag == inkex.addNS('polygon', 'svg') or \
                    node.tag == 'polygon':

                # Convert
                #
                #  <polygon points="x1,y1 x2,y2 x3,y3 [...]"/>
                #
                # to
                #
                #   <path d="Mx1,y1 Lx2,y2 Lx3,y3 [...] Z"/>
                #
                # Note: we ignore polygons with no points

                pl = node.get('points', '').strip()
                if pl == '':
                    pass

                pa = pl.split()
                d = "".join(
                    ["M " + pa[i] if i == 0 else " L " + pa[i] for i in range(
                        0, len(pa))])
                d += " Z"
                self.getPathVertices(d, node, matNew)

            elif node.tag == inkex.addNS('ellipse', 'svg') or \
                    node.tag == 'ellipse' or \
                    node.tag == inkex.addNS('circle', 'svg') or \
                    node.tag == 'circle':

                # Convert circles and ellipses to a path with two 180 degree
                # arcs. In general (an ellipse), we convert
                #
                #   <ellipse rx="RX" ry="RY" cx="X" cy="Y"/>
                #
                # to
                #
                #   <path d="MX1,CY A RX,RY 0 1 0 X2,CY A RX,RY 0 1 0 X1,CY"/>
                #
                # where
                #
                #   X1 = CX - RX
                #   X2 = CX + RX
                #
                # Note: ellipses or circles with a radius attribute of value 0
                # are ignored

                if node.tag == inkex.addNS('ellipse', 'svg') or \
                        node.tag == 'ellipse':
                    rx = float(node.get('rx', '0'))
                    ry = float(node.get('ry', '0'))
                else:
                    rx = float(node.get('r', '0'))
                    ry = rx
                if rx == 0 or ry == 0:
                    pass

                cx = float(node.get('cx', '0'))
                cy = float(node.get('cy', '0'))
                x1 = cx - rx
                x2 = cx + rx
                d = 'M %f,%f ' % (x1, cy) + \
                    'A %f,%f ' % (rx, ry) + \
                    '0 1 0 %f,%f ' % (x2, cy) + \
                    'A %f,%f ' % (rx, ry) + \
                    '0 1 0 %f,%f' % (x1, cy)
                self.mapPathVertices(d, node, matNew)

            elif node.tag == inkex.addNS('pattern', 'svg') or \
                    node.tag == 'pattern':

                pass

            elif node.tag == inkex.addNS('metadata', 'svg') or \
                    node.tag == 'metadata':

                pass

            elif node.tag == inkex.addNS('defs', 'svg') or node.tag == 'defs':

                pass

            elif node.tag == inkex.addNS('desc', 'svg') or node.tag == 'desc':

                pass

            elif node.tag == inkex.addNS('namedview', 'sodipodi') or \
                    node.tag == 'namedview':

                pass

            elif node.tag == inkex.addNS('eggbot', 'svg') or \
                    node.tag == 'eggbot':

                pass

            elif node.tag == inkex.addNS('text', 'svg') or node.tag == 'text':

                inkex.errormsg(
                    'Warning: unable to draw text, '
                    'please convert it to a path first.')

                pass

            elif node.tag == inkex.addNS('title', 'svg') or \
                    node.tag == 'title':

                pass

            elif node.tag == inkex.addNS('image', 'svg') or \
                    node.tag == 'image':

                if 'image' not in self.warnings:
                    inkex.errormsg(
                        gettext.gettext(
                            'Warning: unable to draw bitmap images; '
                            'please convert them to line art first.  '
                            'Consider using the "Trace bitmap..." '
                            'tool of the "Path" menu.  Mac users please '
                            'note that some X11 settings may '
                            'cause cut-and-paste operations to paste in '
                            'bitmap copies.'))
                    self.warnings['image'] = 1
                pass

            elif node.tag == inkex.addNS('pattern', 'svg') or \
                    node.tag == 'pattern':

                pass

            elif node.tag == inkex.addNS('radialGradient', 'svg') or \
                    node.tag == 'radialGradient':

                # Similar to pattern
                pass

            elif node.tag == inkex.addNS('linearGradient', 'svg') or \
                    node.tag == 'linearGradient':

                # Similar in pattern
                pass

            elif node.tag == inkex.addNS('style', 'svg') or \
                    node.tag == 'style':

                # This is a reference to an external style sheet and not the
                # value of a style attribute to be inherited by child elements
                pass

            elif node.tag == inkex.addNS('cursor', 'svg') or \
                    node.tag == 'cursor':

                pass

            elif node.tag == inkex.addNS('color-profile', 'svg') or \
                    node.tag == 'color-profile':

                # Gamma curves, color temp, etc. are not relevant to single
                # color output
                pass

            elif not isinstance(node.tag, basestring):

                # This is likely an XML processing instruction such as an XML
                # comment.  lxml uses a function reference for such node tags
                # and as such the node tag is likely not a printable string.
                # Further, converting it to a printable string likely won't
                # be very useful.

                pass

            else:

                inkex.errormsg(
                    'Warning: unable to draw object <%s>, '
                    'please convert it to a path first.' % node.tag)
                pass

    def recursivelyGetEnclosingTransform(self, node):

        '''
        Determine the cumulative transform which node inherits from
        its chain of ancestors.
        '''
        node = node.getparent()
        if node is not None:
            parent_transform = self.recursivelyGetEnclosingTransform(node)
            node_transform = node.get('transform', None)
            if node_transform is None:
                return parent_transform
            else:
                tr = simpletransform.parseTransform(node_transform)
                if parent_transform is None:
                    return tr
                else:
                    return simpletransform.composeTransform(
                        parent_transform, tr)
        else:
            return self.docTransform

    def effect(self):

        # Viewbox handling
        self.handleViewBox()

        # First traverse the document (or selected items), reducing
        # everything to line segments.  If working on a selection,
        # then determine the selection's bounding box in the process.
        # (Actually, we just need to know it's extrema on the x-axis.)

        if self.options.ids:
            # Traverse the selected objects
            for id in self.options.ids:
                transform = self.recursivelyGetEnclosingTransform(
                    self.selected[id])
                self.recursivelyTraverseSvg([self.selected[id]], transform)
        else:
            # Traverse the entire document building new, transformed paths
            self.recursivelyTraverseSvg(
                self.document.getroot(), self.docTransform)

        # Determine the center of the drawing's bounding box
        self.cx = self.xmin + (self.xmax - self.xmin) / 2.0
        self.cy = self.ymin + (self.ymax - self.ymin) / 2.0

        # Determine which polygons lie entirely within other polygons
        try:
            if '/' == os.sep:
                self.f = open(os.path.expanduser(self.options.fname), 'w')
            else:
                self.f = open(
                    os.path.expanduser(
                        self.options.fname).replace('/', os.sep),
                    'w')

            self.f.write('''
// Module names are of the form poly_<inkscape-path-id>().  As a result,
// you can associate a polygon in this OpenSCAD program with the corresponding
// SVG element in the Inkscape document by looking for the XML element with
// the attribute id=\"inkscape-path-id\".

// fudge value is used to ensure that subtracted solids are a tad taller
// in the z dimension than the polygon being subtracted from.  This helps
// keep the resulting .stl file manifold.
fudge = 0.1;
''')

            for key in self.paths:
                self.f.write('\n')
                self.convertPath(key)

            # Come up with a name for the module based on the file name.
            name = os.path.splitext( os.path.basename( self.options.fname ) )[0]
            # Remove all punctuation except underscore.
            name = re.sub('[' + string.punctuation.replace('_', '') + ']', '', name)

            self.f.write('\nmodule %s(h)\n{\n' % name)

            # Now output the list of modules to call
            self.f.write('\n')
            for call in self.call_list:
                self.f.write(call)

            # The module that calls all the other ones.
            self.f.write('}\n\n%s(%s);\n' % (name, self.options.height))

        except:
            inkex.errormsg('Unable to open the file ' + self.options.fname)


if __name__ == '__main__':
    e = OpenSCAD()
    e.affect()