Parse svg: percorso d attributo

Question

Ho bisogno di decifrare un elemento di percorso in un documento SVG per guidare una macchina CNC lungo quel percorso. Mi chiedo se ci sono delle librerie Python che analizzano SVG e dare una sorta di lista divinatorio per l'attributo d, ad esempio:

<path d="M 20 30 L 20 20 20 40 40 40"/> 

analizza in

[["M", 20, 30], 
["L", 20, 20], 
["L", 20, 40], 
["L", 40, 40]] 

Answer 1

Ecco un inizio è scritto da me e in python 2.7.2. Basta eliminare i test e stampare le dichiarazioni se lo si desidera.

Copyright 2012 Christopher L. Ramsey 

    Licensed under the Apache License, Version 2.0 (the "License"); 
    you may not use this file except in compliance with the License. 
    You may obtain a copy of the License at 

     http://www.apache.org/licenses/LICENSE-2.0 

    Unless required by applicable law or agreed to in writing, software 
    distributed under the License is distributed on an "AS IS" BASIS, 
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
    See the License for the specific language governing permissions and 
    limitations under the License. 

from collections import OrderedDict 
from re import match 
from re import split 
from re import sub 

class PathIterator(object): 
    EOI = 'End of Iteration' 
    PATH_IDENTIFIERS = r'[MLHVCSQTAmlhvcsqa]' 
    NUMBERS = r'[0-9.-^A-z]' 
    SEPERATORS = r'\s|\,' 
    PATH_END = r'[Zz]' 

    def __init__(self, path): 
     self.parseable = path.translate(None, '\t\f') 
     self.parseable = self.parseable.replace('\n', ' ') 
     print 'strip_newlines: {}'.format(self.parseable) 
     self.parseable = sub(r'([A-Za-z])([0-9]|\-)', self.insert, self.parseable) 
     print 'add_space: {}'.format(self.parseable) 
     self.parseable = self.parseable.replace(',', ' ') 
     print 'replace_commas: {}'.format(self.parseable) 
     self.parseable = sub(r'\s+', ' ', self.parseable) # replace any double space with a single space 
     print 'strip_extra_space: {}'.format(self.parseable) 
     self.tokens = split(' ', self.parseable) 
     self.map = self.produce_map(self.tokens) 
     print self.map 
     self.elements = self.process(self.map) 

    def produce_map(self, tkns): 
     self.m = OrderedDict() 
     self.i = 0 
     while self.i < len(tkns): 
      if match(self.PATH_IDENTIFIERS, tkns[self.i]): 
       self.m[self.i] = tkns[self.i] 
      elif match(self.PATH_END, tkns[self.i]): 
       self.m[self.i] = tkns[self.i] 
      else: 
       pass 
      self.i += 1 
     return self.m.items() 

    def process(self, map): 
     self.mm = [] 
     self.l = len(map) 
     for e in range(self.l): 
      try: 
       self.element = map[e] 
       self.future = map[e + 1] 
       self.ident = self.element[1] 
       self.start = self.element[0] + 1 
       self.end = self.future[0] 
       self.nbrs = self.tokens[self.start:self.end] 
      except: 
       self.element = map[e] 
       self.ident = self.element[1] 
       self.start = self.element[0] + 1 
       self.end = len(self.tokens) 
       self.nbrs = self.tokens[self.start:self.end] 
       print 'start: {} end {}'.format(self.start, self.end) 
      finally: 
       self.numbers = [] 
       for number in self.nbrs: 
        self.numbers.append(float(number)) 
       self.mm.append((self.ident, self.numbers)) 
     return iter(self.mm) 

    def next(self): 
     try: 
      return self.elements.next() 
     except: 
      return self.EOI 

    def insert(self, match_obj): 
     self.group = match_obj.group() 
     return '{} {}'.format(self.group[0], self.group[1]) 

if __name__ == '__main__': 
    inkscape_path = "M 12,90 C 8.676,90 6,87.324 6,84 L 6,82 6,14 6,12 c 0,-0.334721 0.04135,-0.6507 0.09375,-0.96875 0.0487,-0.295596 0.09704,-0.596915 0.1875,-0.875 C 6.29113,10.12587 6.302142,10.09265 6.3125,10.0625 6.411365,9.774729 6.5473802,9.515048 6.6875,9.25 6.8320918,8.976493 7.0031161,8.714385 7.1875,8.46875 7.3718839,8.223115 7.5612765,7.995278 7.78125,7.78125 8.221197,7.353194 8.72416,6.966724 9.28125,6.6875 9.559795,6.547888 9.8547231,6.440553 10.15625,6.34375 9.9000482,6.443972 9.6695391,6.580022 9.4375,6.71875 c -0.00741,0.0044 -0.023866,-0.0045 -0.03125,0 -0.031933,0.0193 -0.062293,0.04251 -0.09375,0.0625 -0.120395,0.0767 -0.2310226,0.163513 -0.34375,0.25 -0.1061728,0.0808 -0.2132809,0.161112 -0.3125,0.25 C 8.4783201,7.442683 8.3087904,7.626638 8.15625,7.8125 8.0486711,7.942755 7.9378561,8.077785 7.84375,8.21875 7.818661,8.25713 7.805304,8.30462 7.78125,8.34375 7.716487,8.446782 7.6510225,8.548267 7.59375,8.65625 7.4927417,8.850956 7.3880752,9.071951 7.3125,9.28125 7.30454,9.30306 7.288911,9.3218 7.28125,9.34375 7.2494249,9.4357 7.2454455,9.530581 7.21875,9.625 7.1884177,9.731618 7.1483606,9.828031 7.125,9.9375 7.0521214,10.279012 7,10.635705 7,11 l 0,2 0,68 0,2 c 0,2.781848 2.2181517,5 5,5 l 2,0 68,0 2,0 c 2.781848,0 5,-2.218152 5,-5 l 0,-2 0,-68 0,-2 C 89,10.635705 88.94788,10.279012 88.875,9.9375 88.83085,9.730607 88.78662,9.539842 88.71875,9.34375 88.71105,9.3218 88.69545,9.30306 88.6875,9.28125 88.62476,9.107511 88.549117,8.913801 88.46875,8.75 88.42717,8.6672 88.38971,8.580046 88.34375,8.5 88.28915,8.40279 88.216976,8.31165 88.15625,8.21875 88.06214,8.077785 87.951329,7.942755 87.84375,7.8125 87.700576,7.63805 87.540609,7.465502 87.375,7.3125 87.36383,7.3023 87.35502,7.29135 87.34375,7.28125 87.205364,7.155694 87.058659,7.046814 86.90625,6.9375 86.803679,6.86435 86.701932,6.784136 86.59375,6.71875 c -0.0074,-0.0045 -0.02384,0.0044 -0.03125,0 -0.232039,-0.138728 -0.462548,-0.274778 -0.71875,-0.375 0.301527,0.0968 0.596455,0.204138 0.875,0.34375 0.55709,0.279224 1.060053,0.665694 1.5,1.09375 0.219973,0.214028 0.409366,0.441865 0.59375,0.6875 0.184384,0.245635 0.355408,0.507743 0.5,0.78125 0.14012,0.265048 0.276135,0.524729 0.375,0.8125 0.01041,0.03078 0.02133,0.06274 0.03125,0.09375 0.09046,0.278085 0.1388,0.579404 0.1875,0.875 C 89.95865,11.3493 90,11.665279 90,12 l 0,2 0,68 0,2 c 0,3.324 -2.676,6 -6,6 l -72,0 z" 
    mdn_path = "M10 80 Q 52.5 10, 95 80 T 180 80" 
    w3c_path = "M100,200 C100,100 250,100 250,200 S400,300 400,200" 
    w3c_path_neg = "M-100,200 C100,100 250,100 250,200 S-400,300 400,200" 
    w3c_path_nl = ''' 
      M600,350 l 50,-25 
      a25,25 -30 0,1 50,-25 l 50,-25 
      a25,50 -30 0,1 50,-25 l 50,-25 
      a25,75 -30 0,1 50,-25 l 50,-25 
      a25,100 -30 0,1 50,-25 l 50,-25 
      ''' 
    paths = [inkscape_path, mdn_path, w3c_path, str.strip(w3c_path_nl), w3c_path_neg] 
    for path in paths: 
     p = PathIterator(path) 
     char = '' 
     while char != PathIterator.EOI: 
      char = p.next() 
      print char 

Answer 2

Ottenere il d-stringa può essere giù in un paio di linee che utilizzano svgpathtools, il resto può essere fatto utilizzando le espressioni regolari.

from svgpathtools import svg2paths 
paths, attributes = svg2paths('some_svg_file.svg') 

percorsi è una lista di oggetti svgpathtools percorso (che contengono solo le informazioni della curva, senza colori, stili, ecc). attributi è un elenco di oggetti dizionario degli attributi.

Supponiamo che il percorso che ti interessa è il primo (la 0a) elencato nel vostro SVG, poi per estrarre solo il d-stringa è possibile utilizzare:

d = attributes[0]['d'] # d-string from first path in SVG 

# Now for some regular expressions magic 
import re 
split_by_letters = re.findall('[A-Z|a-z][^A-Z|a-z]*', d) 
split_as_you_want = [] 
for x in split_by_letters: 
    nums = x[1:].replace(',',' ').split() # list of numbers after letter 
    for k in range(len(nums) // 2): 
     split_as_you_want.append([x[0]] + [nums[k]] + [nums[k+1]]) 
print split_as_you_want 

non ho convertire il i numeri nelle stringhe qui come il modo in cui vuoi farlo dipende dal fatto che siano sempre interi e se ti interessi che rimangano in quel modo. Per la maggior parte degli scopi questo può essere fatto con qualcosa di simile al seguente sotto la riga "nums = ...".

for k, n in enumerate(nums): 
    try: 
     nums[k] = int(n) 
    except ValueError: 
     nums[k] = float(n)