modify SVG line width in python using lxml inline CSS style

svg_modify_line_width.ipynb

{
 "metadata": {
  "name": "svg_modify_line_width"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "from IPython.display import SVG\n\n#first create a sample svg file\nsvg_data = \"\"\"\n      <svg>\n      <g>\n        <rect x=\"10\" y=\"10\" width=\"50\" height=\"50\" \n            style=\"fill:white;stroke-width:1;stroke:black\"/>\n        <rect x=\"70\" y=\"70\" width=\"50\" height=\"50\" \n            style=\"fill:white;stroke-width:1;stroke:black\"/>\n      </g>\n      </svg>\"\"\"\nSVG(svg_data)",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "pyout",
       "prompt_number": 30,
       "svg": "<svg>\n      <g>\n        <rect height=\"50\" style=\"fill:white;stroke-width:1;stroke:black\" width=\"50\" x=\"10\" y=\"10\"/>\n        <rect height=\"50\" style=\"fill:white;stroke-width:1;stroke:black\" width=\"50\" x=\"70\" y=\"70\"/>\n      </g>\n      </svg>",
       "text": "<IPython.core.display.SVG at 0x43cdd10>"
      }
     ],
     "prompt_number": 30
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "from lxml import etree\nfrom StringIO import StringIO\n\nclass CSSStyle:\n    \n    def __init__(self, data):\n        self._dict = {}\n        self._dict.update(self._parse_string(data))\n        \n    def __getattr__(self, attrname):\n        return getattr(self._dict, attrname)\n    \n    def _parse_string(self, style):\n        return dict(map(lambda x: x.split(':'), style.split(';')))\n    \n    def tostring(self):\n        return \";\".join(map(lambda x: \"{0}:{1}\".format(*x), self._dict.items()))",
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "f = StringIO(svg_data)\ntree = etree.parse(f)\nelements = tree.findall('//rect') #here change \"rect\" to SVG element you want to modify\n#to achieve more fine-grained control check the XPath docs: http://effbot.org/zone/element-xpath.htm\n\nfor el in elements:\n    style = CSSStyle(el.attrib['style'])\n    style['stroke-width'] = \"2\"\n    print el.tag, style\n    el.attrib['style'] = style.tostring()",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "rect {'stroke': 'black', 'stroke-width': '2', 'fill': 'white'}\nrect {'stroke': 'black', 'stroke-width': '2', 'fill': 'white'}\n"
      }
     ],
     "prompt_number": 35
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "mod_svg = StringIO()\ntree.write(mod_svg)\nmod_svg.seek(0)\nSVG(mod_svg.read())",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "pyout",
       "prompt_number": 29,
       "svg": "<svg>\n      <g>\n        <rect height=\"50\" style=\"stroke:black;stroke-width:2;fill:white\" width=\"50\" x=\"10\" y=\"10\"/>\n        <rect height=\"50\" style=\"stroke:black;stroke-width:2;fill:white\" width=\"50\" x=\"70\" y=\"70\"/>\n      </g>\n      </svg>",
       "text": "<IPython.core.display.SVG at 0x4400710>"
      }
     ],
     "prompt_number": 29
    }
   ],
   "metadata": {}
  }
 ]
}