path: root/support/dxf_export/inkex.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
inkex.py
A helper module for creating Inkscape extensions

Copyright (C) 2005,2010 Aaron Spike <aaron@ekips.org> and contributors

Contributors:
  Aurélio A. Heckert <aurium(a)gmail.com>
  Bulia Byak <buliabyak@users.sf.net>
  Nicolas Dufour, nicoduf@yahoo.fr
  Peter J. R. Moulder <pjrm@users.sourceforge.net>

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 copy
import gettext
import optparse
import os
import random
import re
import sys
from math import *

#a dictionary of all of the xmlns prefixes in a standard inkscape doc
NSS = {
u'sodipodi' :u'http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd',
u'cc'       :u'http://creativecommons.org/ns#',
u'ccOLD'    :u'http://web.resource.org/cc/',
u'svg'      :u'http://www.w3.org/2000/svg',
u'dc'       :u'http://purl.org/dc/elements/1.1/',
u'rdf'      :u'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
u'inkscape' :u'http://www.inkscape.org/namespaces/inkscape',
u'xlink'    :u'http://www.w3.org/1999/xlink',
u'xml'      :u'http://www.w3.org/XML/1998/namespace'
}

def localize():
    domain = 'inkscape'
    if sys.platform.startswith('win'):
        import locale
        current_locale, encoding = locale.getdefaultlocale()
        os.environ['LANG'] = current_locale
        try:
            localdir = os.environ['INKSCAPE_LOCALEDIR'];
            trans = gettext.translation(domain, localdir, [current_locale], fallback=True)
        except KeyError:
            trans = gettext.translation(domain, fallback=True)
    elif sys.platform.startswith('darwin'):
        try:
            localdir = os.environ['INKSCAPE_LOCALEDIR'];
            trans = gettext.translation(domain, localdir, fallback=True)
        except KeyError:
            try:
                localdir = os.environ['PACKAGE_LOCALE_DIR'];
                trans = gettext.translation(domain, localdir, fallback=True)
            except KeyError:
                trans = gettext.translation(domain, fallback=True)
    else:
        try:
            localdir = os.environ['PACKAGE_LOCALE_DIR'];
            trans = gettext.translation(domain, localdir, fallback=True)
        except KeyError:
            trans = gettext.translation(domain, fallback=True)
    #sys.stderr.write(str(localdir) + "\n")
    trans.install()

def debug(what):
    sys.stderr.write(str(what) + "\n")
    return what

def errormsg(msg):
    """Intended for end-user-visible error messages.
    
       (Currently just writes to stderr with an appended newline, but could do
       something better in future: e.g. could add markup to distinguish error
       messages from status messages or debugging output.)
      
       Note that this should always be combined with translation:

         import inkex
         inkex.localize()
         ...
         inkex.errormsg(_("This extension requires two selected paths."))
    """
    if isinstance(msg, unicode):
        sys.stderr.write(msg.encode("UTF-8") + "\n")
    else:
        sys.stderr.write((unicode(msg, "utf-8", errors='replace') + "\n").encode("UTF-8"))

def are_near_relative(a, b, eps):
    if (a-b <= a*eps) and (a-b >= -a*eps):
        return True
    else:
        return False


# third party library
try:
    from lxml import etree
except Exception, e:
    localize()
    errormsg(_("The fantastic lxml wrapper for libxml2 is required by inkex.py and therefore this extension. Please download and install the latest version from http://cheeseshop.python.org/pypi/lxml/, or install it through your package manager by a command like: sudo apt-get install python-lxml\n\nTechnical details:\n%s" % (e,)))
    sys.exit()
    
def check_inkbool(option, opt, value):
    if str(value).capitalize() == 'True':
        return True
    elif str(value).capitalize() == 'False':
        return False
    else:
        raise optparse.OptionValueError("option %s: invalid inkbool value: %s" % (opt, value))

def addNS(tag, ns=None):
    val = tag
    if ns!=None and len(ns)>0 and NSS.has_key(ns) and len(tag)>0 and tag[0]!='{':
        val = "{%s}%s" % (NSS[ns], tag)
    return val

class InkOption(optparse.Option):
    TYPES = optparse.Option.TYPES + ("inkbool",)
    TYPE_CHECKER = copy.copy(optparse.Option.TYPE_CHECKER)
    TYPE_CHECKER["inkbool"] = check_inkbool

class Effect:
    """A class for creating Inkscape SVG Effects"""

    def __init__(self, *args, **kwargs):
        self.document=None
        self.original_document=None
        self.ctx=None
        self.selected={}
        self.doc_ids={}
        self.options=None
        self.args=None
        self.OptionParser = optparse.OptionParser(usage="usage: %prog [options] SVGfile",option_class=InkOption)
        self.OptionParser.add_option("--id",
                        action="append", type="string", dest="ids", default=[], 
                        help="id attribute of object to manipulate")

    def effect(self):
        pass

    def getoptions(self,args=sys.argv[1:]):
        """Collect command line arguments"""
        self.options, self.args = self.OptionParser.parse_args(args)

    def parse(self, filename=None):
        """Parse document in specified file or on stdin"""

        # First try to open the file from the function argument
        if filename != None:
            try:
                stream = open(filename, 'r')
            except Exception:
                errormsg(_("Unable to open specified file: %s") % filename)
                sys.exit()

        # If it wasn't specified, try to open the file specified as
        # an object member
        elif self.svg_file != None:
            try:
                stream = open(self.svg_file, 'r')
            except Exception:
                errormsg(_("Unable to open object member file: %s") % self.svg_file)
                sys.exit()

        # Finally, if the filename was not specified anywhere, use
        # standard input stream
        else:
            stream = sys.stdin

        p = etree.XMLParser(huge_tree=True)
        self.document = etree.parse(stream, parser=p)
        self.original_document = copy.deepcopy(self.document)
        stream.close()

    # defines view_center in terms of document units
    def getposinlayer(self):
        #defaults
        self.current_layer = self.document.getroot()
        self.view_center = (0.0,0.0)

        layerattr = self.document.xpath('//sodipodi:namedview/@inkscape:current-layer', namespaces=NSS)
        if layerattr:
            layername = layerattr[0]
            layer = self.document.xpath('//svg:g[@id="%s"]' % layername, namespaces=NSS)
            if layer:
                self.current_layer = layer[0]

        xattr = self.document.xpath('//sodipodi:namedview/@inkscape:cx', namespaces=NSS)
        yattr = self.document.xpath('//sodipodi:namedview/@inkscape:cy', namespaces=NSS)
        if xattr and yattr:
            x = self.unittouu( xattr[0] + 'px' )
            y = self.unittouu( yattr[0] + 'px')
            doc_height = self.unittouu(self.document.getroot().get('height'))
            if x and y:
                self.view_center = (float(x), doc_height - float(y)) # FIXME: y-coordinate flip, eliminate it when it's gone in Inkscape

    def getselected(self):
        """Collect selected nodes"""
        for i in self.options.ids:
            path = '//*[@id="%s"]' % i
            for node in self.document.xpath(path, namespaces=NSS):
                self.selected[i] = node

    def getElementById(self, id):
        path = '//*[@id="%s"]' % id
        el_list = self.document.xpath(path, namespaces=NSS)
        if el_list:
          return el_list[0]
        else:
          return None

    def getParentNode(self, node):
        for parent in self.document.getiterator():
            if node in parent.getchildren():
                return parent
                break


    def getdocids(self):
        docIdNodes = self.document.xpath('//@id', namespaces=NSS)
        for m in docIdNodes:
            self.doc_ids[m] = 1

    def getNamedView(self):
        return self.document.xpath('//sodipodi:namedview', namespaces=NSS)[0]

    def createGuide(self, posX, posY, angle):
        atts = {
          'position': str(posX)+','+str(posY),
          'orientation': str(sin(radians(angle)))+','+str(-cos(radians(angle)))
          }
        guide = etree.SubElement(
                  self.getNamedView(),
                  addNS('guide','sodipodi'), atts )
        return guide

    def output(self):
        """Serialize document into XML on stdout"""
        original = etree.tostring(self.original_document)        
        result = etree.tostring(self.document)        
        if original != result:
            self.document.write(sys.stdout)

    def affect(self, args=sys.argv[1:], output=True):
        """Affect an SVG document with a callback effect"""
        self.svg_file = args[-1]
        self.getoptions(args)
        self.parse()
        self.getposinlayer()
        self.getselected()
        self.getdocids()
        self.effect()
        if output: self.output()

    def uniqueId(self, old_id, make_new_id = True):
        new_id = old_id
        if make_new_id:
            while new_id in self.doc_ids:
                new_id += random.choice('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
            self.doc_ids[new_id] = 1
        return new_id

    def xpathSingle(self, path):
        try:
            retval = self.document.xpath(path, namespaces=NSS)[0]
        except:
            errormsg(_("No matching node for expression: %s") % path)
            retval = None
        return retval

    #a dictionary of unit to user unit conversion factors
    __uuconv = {'in':96.0, 'pt':1.33333333333, 'px':1.0, 'mm':3.77952755913, 'cm':37.7952755913,
                'm':3779.52755913, 'km':3779527.55913, 'pc':16.0, 'yd':3456.0 , 'ft':1152.0}

    # Function returns the unit used for the values in SVG.
    # For lack of an attribute in SVG that explicitly defines what units are used for SVG coordinates,
    # try to calculate the unit from the SVG width and SVG viewbox.
    # Defaults to 'px' units.
    def getDocumentUnit(self):
        svgunit = 'px' #default to pixels

        svgwidth = self.document.getroot().get('width')
        viewboxstr = self.document.getroot().get('viewBox')
        if viewboxstr:
            unitmatch = re.compile('(%s)$' % '|'.join(self.__uuconv.keys()))
            param = re.compile(r'(([-+]?[0-9]+(\.[0-9]*)?|[-+]?\.[0-9]+)([eE][-+]?[0-9]+)?)')

            p = param.match(svgwidth)
            u = unitmatch.search(svgwidth)    
            
            width = 100 #default
            viewboxwidth = 100 #default
            svgwidthunit = 'px' #default assume 'px' unit
            if p:
                width = float(p.string[p.start():p.end()])
            else:
                errormsg(_("SVG Width not set correctly! Assuming width = 100"))
            if u:
                svgwidthunit = u.string[u.start():u.end()]

            viewboxnumbers = []
            for t in viewboxstr.split():
                try:
                    viewboxnumbers.append(float(t))
                except ValueError:
                    pass
            if len(viewboxnumbers) == 4:  #check for correct number of numbers
                viewboxwidth = viewboxnumbers[2]

            svgunitfactor = self.__uuconv[svgwidthunit] * width / viewboxwidth

            # try to find the svgunitfactor in the list of units known. If we don't find something, ...
            eps = 0.01 #allow 1% error in factor
            for key in self.__uuconv:
                if are_near_relative(self.__uuconv[key], svgunitfactor, eps):
                    #found match!
                    svgunit = key;

        return svgunit


    def unittouu(self, string):
        '''Returns userunits given a string representation of units in another system'''
        unit = re.compile('(%s)$' % '|'.join(self.__uuconv.keys()))
        param = re.compile(r'(([-+]?[0-9]+(\.[0-9]*)?|[-+]?\.[0-9]+)([eE][-+]?[0-9]+)?)')

        p = param.match(string)
        u = unit.search(string)    
        if p:
            retval = float(p.string[p.start():p.end()])
        else:
            retval = 0.0
        if u:
            try:
                return retval * (self.__uuconv[u.string[u.start():u.end()]] / self.__uuconv[self.getDocumentUnit()])
            except KeyError:
                pass
        else: # default assume 'px' unit
            return retval / self.__uuconv[self.getDocumentUnit()]

        return retval

    def uutounit(self, val, unit):
        return val / (self.__uuconv[unit] / self.__uuconv[self.getDocumentUnit()])

    def addDocumentUnit(self, value):
        ''' Add document unit when no unit is specified in the string '''
        try:
            float(value)
            return value + self.getDocumentUnit()
        except ValueError:
            return value

# vim: expandtab shiftwidth=4 tabstop=8 softtabstop=4 fileencoding=utf-8 textwidth=99