Make custom pads editable without exploding and recombining

[eelik]

In the report https://bugs.launchpad.net/kicad/+bug/1775545 I wished for WYSIWYG editing for rectangular (and round) pads. Together with that it would also be nice to be able to edit custom shaped pads without first exploding them and especially recombining them afterwards. It's quite tedious to first explode, then edit, then select the shape and the pad and then combine. This was especially difficult when I edited pads on different layers: copper, mask and paste, each of them shaped a bit differently, on top of each other. In that case I can't even select pads to be combined with selection box; every time I have to use the clarification menu (and unfortunately the great "highlight the hovered item" feature doesn't work in Windows).

This could behave so that the pad would be kind of exploded automatically. The anchor pad would stay where it is. It could prevent moving the zone outlines outside the the anchor point. Or it would do the combining phase automatically when the editing is over (the polygon is unselected) and give the normal error message if the anchor point is outside the changed polygon.

There are two alternative behaviors: 1. In implementation level the pad is not actually exploded, the edges are just moved. 2. In implementation level (and in visible level) the pad is actually exploded, but the connection between the anchor pad and the graphic polygon is kept and they are combined back together automatically when the polygon is deselected.

Custom pads in the copper layers can now be selected and moved like basic pads. To keep it that way there could be a context menu action, like in the bug #1775545. "Resize" or maybe "Edit in place". It would still lessen the steps by removing the need to re-select and combine the items again and again.

Maybe it could be possible to simply add automatic re-combining to the current behavior. Even that would make the whole process of editing custom pads easier.

[KiCad Janitor (kicad-janitor)]

KiCad bug tracker has moved to Gitlab. This report is now available here: https://gitlab.com/kicad/code/kicad/-/issues/2305