Adjust polyline/polygon parsing to W3C specification

https://www.w3.org/TR/SVG11/shapes.html#PointsBNF

svgpathtools/svg2paths.py

@@ -5,10 +5,16 @@ The main tool being the svg2paths() function."""
 from __future__ import division, absolute_import, print_function
 from xml.dom.minidom import parse
 from os import path as os_path, getcwd
+import re
 
 # Internal dependencies
 from .parser import parse_path
 
+COORD_PAIR_TMPLT = re.compile(
+    r'([\+-]?\d*[\.\d]\d*[eE][\+-]?\d+|[\+-]?\d*[\.\d]\d*)' +
+    r'(?:\s*,\s*|\s+|(?=-))' +
+    r'([\+-]?\d*[\.\d]\d*[eE][\+-]?\d+|[\+-]?\d*[\.\d]\d*)'
+)
 
 def ellipse2pathd(ellipse):
     """converts the parameters from an ellipse or a circle to a string for a 
@@ -37,19 +43,21 @@ def ellipse2pathd(ellipse):
     return d
 
 
-def polyline2pathd(polyline_d):
+def polyline2pathd(polyline_d, is_polygon=False):
     """converts the string from a polyline points-attribute to a string for a
     Path object d-attribute"""
-    points = polyline_d.replace(', ', ',')
-    points = points.replace(' ,', ',')
-    points = points.split()
+    points = COORD_PAIR_TMPLT.findall(polyline_d)
+    closed = (float(points[0][0]) == float(points[-1][0]) and
+              float(points[0][1]) == float(points[-1][1]))
 
-    closed = points[0] == points[-1]
+    # The `parse_path` call ignores redundant 'z' (closure) commands
+    # e.g. `parse_path('M0 0L100 100Z') == parse_path('M0 0L100 100L0 0Z')`
+    # This check ensures that an n-point polygon is converted to an n-Line path.
+    if is_polygon and closed:
+        points.append(points[0])
 
-    d = 'M' + points.pop(0).replace(',', ' ')
-    for p in points:
-        d += 'L' + p.replace(',', ' ')
-    if closed:
+    d = 'M' + 'L'.join('{0} {1}'.format(x,y) for x,y in points)
+    if is_polygon or closed:
         d += 'z'
     return d
 
@@ -59,23 +67,7 @@ def polygon2pathd(polyline_d):
     Path object d-attribute.
     Note:  For a polygon made from n points, the resulting path will be
     composed of n lines (even if some of these lines have length zero)."""
-    points = polyline_d.replace(', ', ',')
-    points = points.replace(' ,', ',')
-    points = points.split()
-
-    reduntantly_closed = points[0] == points[-1]
-
-    d = 'M' + points[0].replace(',', ' ')
-    for p in points[1:]:
-        d += 'L' + p.replace(',', ' ')
-
-    # The `parse_path` call ignores redundant 'z' (closure) commands
-    # e.g. `parse_path('M0 0L100 100Z') == parse_path('M0 0L100 100L0 0Z')`
-    # This check ensures that an n-point polygon is converted to an n-Line path.
-    if reduntantly_closed:
-        d += 'L' + points[0].replace(',', ' ')
-
-    return d + 'z'
+    return polyline2pathd(polyline_d, True)
 
 
 def rect2pathd(rect):