Python script, ASCII text executable
title: Using boolean operations in an Inkscape extension topics: ["inkscape", "python", "tip"] DATE: 2025-11-22 ---
I've wasted 3 days doing this, so I will at least publish my findings on the web so you don't have to waste another 3 days. I wasn't able to find a good example online and the docs are not well-made (not saying that they should be a priority), so figuring it out does require some code research.
The inkex module provides lots of things, but boolean operations aren't one of
them. Thus, you will have to call Inkscape yourself; luckily, inkex does
provide that.
Even though they are listed as arguments, no special processing is done to the values, which are still strings.
I leave a minimal example:
import inkex
import io
class UnionTwoPaths(inkex.EffectExtension):
def effect(self):
selected = list(self.svg.selection)
if len(selected) != 2:
inkex.errormsg("Select exactly two paths!")
return
# Make a string of the IDs
ids = ",".join([elem.get_id() for elem in selected])
# Call Inkscape to make a union
union_svg_bytes = inkex.command.inkscape_command(
self.document,
select=ids,
actions="path-union"
)
# Send the drawing back
self.document = inkex.load_svg(union_svg_bytes)
if __name__ == "__main__":
UnionTwoPaths().run()
<?xml version="1.0" encoding="UTF-8"?>
<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
<name>Union of two paths</name>
<id>org.inkscape.boolean.union_two_paths</id>
<effect>
<!-- Enable only on path objects (could use 'all' if preferred) -->
<object-type>path</object-type>
<effects-menu>
<submenu name="Generate from Path"/>
</effects-menu>
</effect>
<script>
<command reldir="extensions" interpreter="python">union_two_paths.py</command>
</script>
</inkscape-extension>
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---
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title: Using boolean operations in an Inkscape extension
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topics: ["inkscape", "python", "tip"]
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DATE: 2025-11-22
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---
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I've wasted 3 days doing this, so I will at least publish my findings on the web
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so you don't have to waste another 3 days. I wasn't able to find a good example
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online and the docs are not well-made (not saying that they should be a
10
priority), so figuring it out does require some code research.
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The `inkex` module provides lots of things, but boolean operations aren't one of
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them. Thus, you will have to call Inkscape yourself; luckily, `inkex` does
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provide that.
15
Even though they are listed as arguments, no special processing is done to the
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values, which are still strings.
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I leave a minimal example:
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~~~python
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import inkex
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import io
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class UnionTwoPaths(inkex.EffectExtension):
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def effect(self):
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selected = list(self.svg.selection)
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if len(selected) != 2:
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inkex.errormsg("Select exactly two paths!")
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return
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# Make a string of the IDs
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ids = ",".join([elem.get_id() for elem in selected])
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# Call Inkscape to make a union
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union_svg_bytes = inkex.command.inkscape_command(
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self.document,
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select=ids,
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actions="path-union"
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)
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# Send the drawing back
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self.document = inkex.load_svg(union_svg_bytes)
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if __name__ == "__main__":
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UnionTwoPaths().run()
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~~~
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~~~xml
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<?xml version="1.0" encoding="UTF-8"?>
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<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
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<name>Union of two paths</name>
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<id>org.inkscape.boolean.union_two_paths</id>
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<effect>
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<!-- Enable only on path objects (could use 'all' if preferred) -->
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<object-type>path</object-type>
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<effects-menu>
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<submenu name="Generate from Path"/>
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</effects-menu>
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</effect>
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<script>
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<command reldir="extensions" interpreter="python">union_two_paths.py</command>
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</script>
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</inkscape-extension>
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~~~
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