Trying to add dragging Diff Pair

[Y. HB (sprhawk)]

Original Post is here

I’m working on drawing a SoC board with KiCAD, but I find KiCAD does not 1 support dragging a differential pair, so I cloned KiCAD source code to see if I can add it.

I found the dev docs and video, but the dev docs are too simple and not a source code walk through, and the content of video was a bit older (5.x) than latest (7.0) source code

So I have to read through source code directly.

IMO, I can learn from drag tool and tune diff pair tool.

I think I can add a DRAG_MODE in pns_router.h
add static TOOL_ACTION routerDragDiffPair; in pcb_actions.h

I think I can copy most part of length_tuner_tool, but need to change some in pns_router.cpp