It's far from finished, but the overall architecture is there. See the docs for an overview of horizon's top features.

Wanna chat about the project? Join #horizon on freenode

• Complete design flow from schematic entry to gerber export
• Sane library management
• Unified editor for everything from symbol to board
• Netlist-aware schematic editor
• KiCad's awesome interactive router
• Lag- and glitch-free rendering
• Rule-based DRC
• Undo/redo
• Copy/paste for some objects
• Builds and runs on Linux and Windows

• Written in modern C++, legacy-free codebase!
• Uses JSON as on-disk format
• Uses Gtkmm3 for GUI
• OpenGL 3 accelerated rendering
• Everything is referenced by UUIDs

See the the docs

• https://github.com/nlohmann/json/
• http://www.angusj.com/delphi/clipper.php
• https://github.com/ivanfratric/polypartition/
• https://github.com/jhasse/poly2tri
• https://qcad.org/en/what-is-dxflib
• https://git.launchpad.net/kicad/tree/pcbnew/router
• https://github.com/russdill/pybis