Update inkscape-centerline-trace.py

inkscape-centerline-trace.py

@@ -4,10 +4,13 @@
 # as a path along the centerline of the strokes.
 #
 # This is done with autotrace -centerline, as
-# the builtin potrace in inkscape cannot do centerline.
-# It will always draw a path around the contour of the 
+# the builtin potrace in inkscape cannot do centerline --
+# it would always draw a path around the contour of the 
 # stroke, resulting in double lines.
 #
+# We want a stroke represented by a single path (optionally with line-width) , 
+# rather than its outline contour.
+#
 # Algorithm:
 # autotrace needs a bi-level bitmap. In order to find the
 # best threshold value, we run autotrace at multiple thresholds