解析svg：路徑d屬性

Question

我需要解密SVG文檔中的路徑元素以驅動沿該路徑的CNC機器。我不知道是否有解析SVG並給予某種Python的列表爲d屬性的任何Python庫，如：

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

解析成

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

Answer 1

這裏是一個開始它是由我和書面python 2.7.2。只要刪除測試和打印報表，如果你想。

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

獲取d-string可以是倒在使用svgpathtools幾行，其餘的可以使用正則表達式來完成。

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

路徑是svgpathtools路徑對象（只包含曲線信息，沒有顏色，款式等）的列表。 屬性是屬性的字典對象列表。

假設您有興趣的路徑是第一（第0）在你的SVG上市，那麼只提取d串您可以使用：

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 

我沒有轉換數字轉換爲字符串，因爲你想怎麼做取決於它們是否總是整數，以及你是否在乎它們保持那種方式。對於大多數目的來說，這可以通過類似於下面的「nums = ...」行來完成。

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