Python modules for extensions

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These modules are provided as part of Inkscape and can be found in /usr/share/inkscape/extentions on GNU/Linux, ... on Windows, and ... on Mac OS X along with the extensions bundled with Inkscape. They can be imported from an extension as any other python module.

This module encapsulates the basic behavior of a script extension, allowing the author to concentrate on manipulating the SVG data. It relies on lxml.etree to work with the XML tree. was originally designed to provide the Effect (filter) extension type, but has been used for Input/Output extensions simply by overriding additional class methods.

Functions provides the following functions:

errormsg( msg )
End-user visible error message, it should always be used with translation: inkex.errormsg(_("This extension requires two selected paths"))
addNS( tag, ns=None )
Returns the selected tag, with the namespace applied. The namespace is selected from a list supplied with the module.

The Effect class

The most important part of is the Effect class. To implement an effect type extension in python see PythonEffectTutorial


You should overwrite this method with your own, as show in PythonEffectTutorial#Effect Extension Script
getElementById( id )
Returns the firs found element with given id, as a lxml element.
getParentNode( node )
Returns the parent of node. Probably the same as node.getparent() from lxml?
createGuid( x, y, angle )
Creates guide at position (x,y), with angle angle.
Actuate the script.
xpathSingle( path )
An xpath wrapper to return a single node.
uniqueId( old_id )
Return an id that is unique in the document given a proposed id, by appending random alphanumeric characters to it.
Return width of document, as a string.
Return height of document, as a string.
Return a string representing the default unit for the document. Full list of possible units is defined in the module.
unittouu( string )
Convert given value (as a string, e.g: "4px") to units used by the document. Returns float.
uutounit( value, unit )
Convert a value (float) in document default units to given units.


DOM document, as a lxml.etree.
A dict mapping ids to nodes, for all nodes selected in Inkscape.
A dict mapping ids to the constant 1, for all of the ids used in the original document. Does not get automatically updated when adding elements.
Options passed to the script.

Provides methods for dealing with css data embeded in SVG's style="" atribute

  • parseStyle(string): Create a dictionary from the value of an inline style attribute
  • formatStyle(dict): Format an inline style attribute from a dictionary
  • isColor(c): Determine if its a color we can use. If not, leave it unchanged.
  • parseColor(c): Creates a rgb int array
  • formatColoria(a): int array to #rrggbb
  • formatColorfa(a): float array to #rrggbb
  • formatColor3i(r,g,b): 3 ints to #rrggbb
  • formatColor3f(r,g,b): 3 floats to #rrggbb
  • svgcolors: a dictionary defining legal color names and corresponding color values

Provides functions to round trip svg path d="" attribute data and a simple path format mimicing that datastructure. additional functions for scaling translating and rotating path data.

An alternative path representation. access both handles of a node at once. loses a paths open/closed identity.

Provides code to easily transform objects.

  • parseTransform
Takes a string such as rotate(10) and produces a transformation matrix. If you also supply an initial matrix, the new one will be composed with the old one.
Available commands: translate, scale, rotate, skewX, skewY, matrix. Other examples:
matrix = parseTransform('rotate(10)')
matrix = parseTransform('skewY(10)')
matrix = parseTransform('translate(10 10)')
matrix = parseTransform(' rotate(10)')
matrix = parseTransform('translate(700,210) rotate(-30)')

Provides turtle graphics primitives with svg path data output

Utility functions for working with bezier curves

Decompose a path into polylines


an obscure set of tools for dealing with musical scales.