Also adds some debugging to try to catch dangling pointers.
Also adds a cache for group bounding boxes (which will be expensive
to calculate for large groups).
Fixes https://gitlab.com/kicad/code/kicad/issues/12875
1) The highest priority zone that a via/pad collides with "owns" its
connectivity state. Once set, lower priority zones cannot change it --
and in fact, if they would have connected to it are forced not to.
2) The connectivity state goes with the zone fill state, and therefore
must be saved in the file.
3) Display of remove-unconnected's pads is no longer done in GetViewLOD()
(which isn't called for selected items), and is instead done in PCB_PAINTER.
This allows us to draw the full pad in outline mode when a via/pad is
selected which would otherwise only show the hole.
4) Note that in some cases this will still generate DRC errors -- in
particular when a via nearly collides with a higher priority zone it
won't get "owned" by that zone and may therefore have insufficient
clearance if said zone concludes it's unconnected and a subsequent
(lower priority) zone connects to it (causing it to now become flashed).
Fixes https://gitlab.com/kicad/code/kicad/issues/11299
Before dereferencing the front of the sequence, we have to ensure that
the pad exists on any layer. If not, just return the default (probably
F_Cu) for the element
When building the connectivity database, we should not be using the
connectivity to check for shapes.
To make this deterministic, we introduce two flags (ALWAYS_FLASH and
NEVER_FLASH) that are used with connectivity building to determine
whether a pad is flashed for connectivity or not. ZONE <-> PAD/VIA
connectivity will be checked with ALWAYS_FLASHED and all other
connectivity will be checked with NEVER_FLASHED if they are marked for
potential annular ring removal. If they are not marked for removal,
they will be checked ALWAYS_FLASHED.
Fixes https://gitlab.com/kicad/code/kicad/issues/11114
Jon Evans
Jeff Young
Alex
Marek Roszko
Maciej Suminski
Seth Hillbrand
jean-pierre charras