Clipper2 support

[sikmir]

https://sourceforge.net/projects/polyclipping/:

This library is now obsolete and no longer being maintained.
It has been superceded by my Clipper2 library - https://github.com/AngusJohnson/Clipper2

Benchmark comparison of Clipper1 and Clipper2 performance: https://www.angusj.com/clipper2/Docs/Changes.htm

[lpechacek]

Clipper2 migration has been long sitting on my list. So, I gave a shot at the migration and it seems viable: LibreMapper/mapper@06584e4

As a side note, I first touched on the Clipper2 topic with Google Gemini. I'm not a super-fan of the AI boom, but I wanted to get in touch with today's world and test the system on a topic where I can tell whether the response is relevant. And surprise, Gemini did slightly better on the coding than I did. I gave the robot boolean_tool.cpp file and told it to rewrite it for Clipper2 API. It did the coding job as good as I did (the changes are more or less trivial) and even fixed Clipper class names in comments (which is what I forgot to do). On the other hand, it lost parts of Doxygen comments block and perhaps a few lines of code that it could not understand.

The chatbot conversation served as a starting point for assessing the complexity of the migration and gave me useful hints for the actual code change. In the end, I spent about eight-times more time on the CMake script adjustments than on the C++ coding.

[lpechacek]

The OO implementation may look like this:
BooleanTool: Add test
[DRAFT] Migrate to Clipper2
The code does what it's supposed to do but certainly needs some rework before merging into OpenOrienteering.

Two notable points - Clipper2 requires C++17 and it handles XOr differently than Polyclipping. Otherwise, it seems to be a 1:1 replacement for Polyclipping.

[sikmir]

Just out of curiosity, how LibreMapper/mapper differs from OO mapper? Any new features?

[lpechacek]

Just out of curiosity, how LibreMapper/mapper differs from OO mapper? Any new features?

As this is off-topic, just a quick response.

• It accepts lower quality code than OpenOrienteering but it moves faster. I'm trading speed for quality.
• It has two variants - mainline, which still 100 % OO Mapper compatibility in file format, and experimental which contains forward looking features and work in progress features.
• It has not seen any releases as I haven't been able to produce Windows and Android packages yet. There are so many options but I haven't yet found any that is easy to implement.

LibreMapper may matter for OpenOrienteering as a source of sample code that may be reworked to match OpenOrienteering standards. It has the maintenance stuff like switch to Qt6 and Clipper upgrade in.