Scripting Inkscape – kinda

A couple of months back at the GTALUG Graphics session, someone asked if Inkscape – the 2D vector graphics workhorse that everyone seems to use – could be scripted. We pretty much said that it couldn’t. Recently, I found out that it does support a limited form of scripting, and wish to pass this on.

The key to it is understanding Inkscape’s command verbs. These can be listed using:

inkscape --verb-list

These verbs map to Inkscape commands, and often have names linked to the menu they live in (such as “FileQuit” doing what you’d expect).

I had a task I had to repeat on many files: convert all the stroked lines to filled paths. You’d need to do this if you are laser engraving a simple drawing, but there are other applications for this too. Here’s a command that would do this for all objects in a drawing, and overwrite the input file:

inkscape --verb EditSelectAll --verb SelectionUnGroup \
        --verb EditSelectAll --verb SelectionUnGroup \
        --verb EditSelectAll --verb SelectionUnGroup \
        --verb EditSelectAll --verb ObjectToPath \
        --verb EditSelectAll --verb SelectionCombine \
        --verb EditSelectAll --verb StrokeToPath \
        --verb FileSave --verb FileClose \
        --verb FileQuit input.svg

What this does:

1. Selects everything, and ungroups all objects (×3, to break up most nested groups);
2. Selects everything, and converts all objects to paths (so text, circles, polygons, spirals become paths, the lowest-level SVG object);
3. Selects everything, and combines everything into one path;
4. Selects everything, and converts all strokes to filled paths (so a two node straight line 1 mm wide would become a four node filled rectangle 1 mm thick);
5. Overwrite the input file, close it, and quit.

The process has some disadvantages:

1. It opens a window every time. You can’t execute verbs without the GUI opening.
2. You can’t have another copy of Inkscape open while you do this.
3. Realistically, you can’t really do anything at your computer until this is done, as it’s popping up windows and shifting focus like crazy. (ssh types can say “heh!” in a smug manner now)
4. You can’t set parameters to verbs.
5. It will overwrite the input file.
6. It clogs up your “File / Recent” menu with all of the files you scripted.