marseymoji/svg_cleaner.py

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#!/usr/bin/env python
# Copyright 2015 Google, Inc. All Rights Reserved.
#
# 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.
#
# Google Author(s): Doug Felt
"""Clean SVG.
svgo could do this, but we're fussy. Also, emacs doesn't understand
that 'style' defaults to 'text/css' and svgo strips this out by
default.
The files we're getting that are exported from AI contain lots of extra
data so that it can reimport the svg, and we don't need it."""
import argparse
import codecs
import logging
import os
from os import path
import re
import sys
from nototools import tool_utils
from xml.parsers import expat
from xml.sax import saxutils
# Expat doesn't allow me to identify empty tags (in particular, with an
# empty tag the parse location for the start and end is not the same) so I
# have to take a dom-like approach if I want to identify them. There are a
# lot of empty tags in svg. This way I can do some other kinds of cleanup
# as well (remove unnecessary 'g' elements, for instance).
# Use nodes instead of tuples and strings because it's easier to mutate
# a tree of these, and cleaner will want to do this.
class _Elem_Node(object):
def __init__(self, name, attrs, contents):
self.name = name
self.attrs = attrs
self.contents = contents
def __repr__(self):
line = ["elem(name: '%s'" % self.name]
if self.attrs:
line.append(" attrs: '%s'" % self.attrs)
if self.contents:
line.append(" contents[%s]: '%s'" % (len(self.contents), self.contents))
line.append(')')
return ''.join(line)
class _Text_Node(object):
def __init__(self, text):
self.text = text
def __repr__(self):
return "text('%s')" % self.text
class SvgCleaner(object):
"""Strip out unwanted parts of an svg file, primarily the xml declaration and
doctype lines, comments, and some attributes of the outermost <svg> element.
The id will be replaced when it is inserted into the font. viewBox causes
unwanted scaling when used in a font and its effect is difficult to
predict. version is unneeded, xml:space is ignored (we're processing spaces
so a request to maintain them has no effect). enable-background appears to
have no effect. x and y on the outermost svg element have no effect. We
keep width and height, and will elsewhere assume these are the dimensions
used for the character box."""
def __init__(self):
self.reader = SvgCleaner._Reader()
self.cleaner = SvgCleaner._Cleaner()
self.writer = SvgCleaner._Writer()
class _Reader(object):
"""Loosely based on fonttools's XMLReader. This generates a tree of nodes,
either element nodes or text nodes. Successive text content is merged
into one node, so contents will never contain more than one _Text_Node in
a row. This drops comments, xml declarations, and doctypes."""
def _reset(self, parser):
self._stack = []
self._textbuf = []
def _start_element(self, name, attrs):
self._flush_textbuf()
node = _Elem_Node(name, attrs, [])
if len(self._stack):
self._stack[-1].contents.append(node)
self._stack.append(node)
def _end_element(self, name):
self._flush_textbuf()
if len(self._stack) > 1:
self._stack = self._stack[:-1]
def _character_data(self, data):
if len(self._stack):
self._textbuf.append(data)
def _flush_textbuf(self):
if self._textbuf:
node = _Text_Node(''.join(self._textbuf))
self._stack[-1].contents.append(node)
self._textbuf = []
def from_text(self, data):
"""Return the root node of a tree representing the svg data."""
parser = expat.ParserCreate()
parser.StartElementHandler = self._start_element
parser.EndElementHandler = self._end_element
parser.CharacterDataHandler = self._character_data
self._reset(parser)
parser.Parse(data)
return self._stack[0]
class _Cleaner(object):
def _clean_elem(self, node):
viewBox, width, height = None, None, None
nattrs = {}
for k, v in node.attrs.items():
if node.name == 'svg' and k in [
'x', 'y', 'id', 'version', 'viewBox', 'width', 'height',
'enable-background', 'xml:space', 'xmlns:graph', 'xmlns:i',
'xmlns:x']:
if k == 'viewBox':
viewBox = v
elif k == 'width':
width = v
elif k == 'height':
height = v
elif k.startswith('xmlns:') and 'ns.adobe.com' not in v:
# keep if not an adobe namespace
logging.debug('keep "%s" = "%s"' % (k, v))
nattrs[k] = v
logging.debug('removing %s=%s' % (k, v))
continue
v = re.sub('\s+', ' ', v)
nattrs[k] = v
if node.name == 'svg':
if not width or not height:
if not viewBox:
raise ValueError('no viewBox, width, or height')
width, height = viewBox.split()[2:]
nattrs['width'] = width
nattrs['height'] = height
node.attrs = nattrs
# scan contents. remove any empty text nodes, or empty 'g' element nodes.
# if a 'g' element has no attrs and only one subnode, replace it with the
# subnode.
wpos = 0
for n in node.contents:
if isinstance(n, _Text_Node):
if not n.text:
continue
elif n.name == 'g':
if not n.contents:
continue
if 'i:extraneous' in n.attrs:
del n.attrs['i:extraneous']
if not n.attrs and len(n.contents) == 1:
n = n.contents[0]
elif n.name == 'i:pgf' or n.name == 'foreignObject':
continue
elif n.name =='switch' and len(n.contents) == 1:
n = n.contents[0]
elif n.name == 'style':
# some emacsen don't default 'style' properly, so leave this in.
if False and n.attrs.get('type') == 'text/css':
del n.attrs['type']
node.contents[wpos] = n
wpos += 1
if wpos < len(node.contents):
node.contents = node.contents[:wpos]
def _clean_text(self, node):
text = node.text.strip()
# common case is text is empty (line endings between elements)
if text:
# main goal here is to leave linefeeds in for style elements
text = re.sub(r'[ \t]*\n+[ \t]*', '\n', text)
text = re.sub(r'[ \t]+', ' ', text)
node.text = text
def clean(self, node):
if isinstance(node, _Text_Node):
self._clean_text(node)
else:
# do contents first, so we can check for empty subnodes after
for n in node.contents:
self.clean(n)
self._clean_elem(node)
class _Writer(object):
"""For text nodes, replaces sequences of whitespace with a single space.
For elements, replaces sequences of whitespace in attributes, and
removes unwanted attributes from <svg> elements."""
def _write_node(self, node, lines, indent):
"""Node is a node generated by _Reader, either a TextNode or an
ElementNode. Lines is a list to collect the lines of output. Indent is
the indentation level for this node."""
if isinstance(node, _Text_Node):
if node.text:
lines.append(node.text)
else:
margin = ' ' * indent
line = [margin]
line.append('<%s' % node.name)
# custom sort attributes of svg, yes this is a hack
if node.name == 'svg':
def svgsort(k):
if k == 'width': return (0, None)
elif k == 'height': return (1, None)
else: return (2, k)
ks = sorted(node.attrs.keys(), key=svgsort)
else:
def defsort(k):
if k == 'id': return (0, None)
elif k == 'class': return (1, None)
else: return (2, k)
ks = sorted(node.attrs.keys(), key=defsort)
for k in ks:
v = node.attrs[k]
line.append(' %s=%s' % (k, saxutils.quoteattr(v)))
if node.contents:
line.append('>')
lines.append(''.join(line))
for elem in node.contents:
self._write_node(elem, lines, indent + 1)
line = [margin]
line.append('</%s>' % node.name)
lines.append(''.join(line))
else:
line.append('/>')
lines.append(''.join(line))
def to_text(self, root):
# set up lines for recursive calls, let them append lines, then return
# the result.
lines = []
self._write_node(root, lines, 0)
return '\n'.join(lines)
def tree_from_text(self, svg_text):
return self.reader.from_text(svg_text)
def clean_tree(self, svg_tree):
self.cleaner.clean(svg_tree)
def tree_to_text(self, svg_tree):
return self.writer.to_text(svg_tree)
def clean_svg(self, svg_text):
"""Return the cleaned svg_text."""
tree = self.tree_from_text(svg_text)
self.clean_tree(tree)
return self.tree_to_text(tree)
def clean_svg_files(in_dir, out_dir, match_pat=None, clean=False):
regex = re.compile(match_pat) if match_pat else None
count = 0
if clean and path.samefile(in_dir, out_dir):
logging.error('Cannot clean %s (same as in_dir)', out_dir)
return
out_dir = tool_utils.ensure_dir_exists(out_dir, clean=clean)
cleaner = SvgCleaner()
for file_name in os.listdir(in_dir):
if regex and not regex.match(file_name):
continue
in_path = os.path.join(in_dir, file_name)
logging.debug('read: %s', in_path)
with open(in_path) as in_fp:
result = cleaner.clean_svg(in_fp.read())
out_path = os.path.join(out_dir, file_name)
with codecs.open(out_path, 'w', 'utf-8') as out_fp:
logging.debug('write: %s', out_path)
out_fp.write(result)
count += 1
if not count:
logging.warning('Failed to match any files')
else:
logging.info('Wrote %s files to %s', count, out_dir)
def main():
parser = argparse.ArgumentParser(
description="Generate 'cleaned' svg files.")
parser.add_argument(
'in_dir', help='Input directory.', metavar='dir')
parser.add_argument(
'-o', '--out_dir', help='Output directory, defaults to sibling of in_dir',
metavar='dir')
parser.add_argument(
'-c', '--clean', help='Clean output directory', action='store_true')
parser.add_argument(
'-r', '--regex', help='Regex to select files, default matches all files.',
metavar='regex', default=None)
parser.add_argument(
'-l', '--loglevel', help='log level name/value', default='warning')
args = parser.parse_args()
tool_utils.setup_logging(args.loglevel)
if not args.out_dir:
if args.in_dir.endswith('/'):
args.in_dir = args.in_dir[:-1]
args.out_dir = args.in_dir + '_clean'
logging.info('Writing output to %s', args.out_dir)
clean_svg_files(
args.in_dir, args.out_dir, match_pat=args.regex, clean=args.clean)
if __name__ == '__main__':
main()