Lindenmayer / Path turtle: correct coordinate system
What does the merge request do?
Fix https://bugs.launchpad.net/inkscape/+bug/1094627
For Lindenmayer, "Turn left" and "Turn right" were inverted. This was due to an error in turtle.py - the y axis in SVG looks down so a left rotation has a negative sign.
Entering the examples on Wikipedia now gives identically oriented results.
Question: can we change this behavior? turtle is used in 2 extensions in mightyscape, so it's rather rare. But it's still a breaking change without warning.
Answer: We're not changing the API, it's the API being broken. Even if users are affected, a simple Mirror command is all it takes to fix this on user side.
Implementation notes
Added unit tests for a simple Koch snowflake and a Sierpinski triangle to test multiple rules.
Summary for release notes
A bug in the rotation sense of the Lindenmayer extension has been fixed.
Checklist
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Add unit tests (if applicable) -
Changes to inkex/
are well documented -
Clean merge request history