Introduction

This program cleans inline style definition, removing properties that are not necessary to proper render image.

1. Some properties don't apply to all SVG tags — for example markers ("arrows") applies only to paths. And such properties could be removed if present in style of other elements.

   Enabled with option -a

2. Some properties has the same value as property of parent node. If a property inherits than setting it again in a child node isn't needed. For example:

   <svg ...>
   <g style="stroke-width: 2px">
          <line style="stroke-width: 2px" x1=.../>
          <line style="stroke-width: 3px" x1=.../>
          <line style="stroke-width: 2px" x1=.../>
          <line style="stroke-width: 2px" x1=.../>
   </g>
   </svg>
   

   After transformation:

   <svg ...>
   <g style="stroke-width: 2px">
          <line x1=.../>
          <line style="stroke-width: 3px" x1=.../>
          <line x1=.../>
          <line x1=.../>
   </g>
   </svg>
   

   Enabled with option -i

3. Properties that has default value are removed too.

   Enabled with option -i

Since program doesn't know anything about CSS, methods 2 and 3 could be safety used with files not using local or external stylesheets.

Experiment result

Here are sizes of SVG files I've drawn using Inkscape and files after lifting.

Columns:

• A - size of original file
• B - no clean - just print xml tree using built-in method (single option -f file)
• C - removed properties that not apply to certain SVG tag (options -a -f file)
• D - removed redundant properties (inherited/default value) (options -i -f file)
• I - both methods (options -i -a -f file)

Summary: in the best case file size was reduced about 52%; average ratio: 65%.

Downloads

• svg_style_cleanup.py (16kB)

Author

Wojciech Muła, wojciech_mula@poczta.onet.pl BSD license