This is the directory with Inkscape's stock patterns. They are
stored in the defs of the SVG document patterns.svg. Within
Inkscape, they can be accessed via the pattern fill option on either
Fill or Stroke tab of the Fill & Stroke dialog (Ctrl+Shift+F). You
can also create a new pattern from selected objects by the Objects
to Pattern command.

Internationalization

This file is internationalized the same way as share/filters/filters/svg
The i18n.py script called from the makefile will extract strings from
patterns.svg into a patterns.svg.h file. Intltool is then able to extracts
these strings just like from normal .h files.

