Adds QA checks to copper sliver tests. Adds the following checks:
- Dot product between two arms (quickly avoids checks for >90°)
- Checks the sliver is convex (area test)
- Eliminates minor slivers with angles that are approximately 0 and ones
with the opposite side width beneath a configurable level
- Updates Clipper2 to fix a couple of jagged edges on inflate
- Adds simplify during zone fill inflation to limit jaggies
Fixes https://gitlab.com/kicad/code/kicad/issues/14549
Currently this lives behind the advanced config flag `UseClipper2`.
Enabling this flag will route all Clipper-based calls through the
Clipper2 library instead of the older Clipper. The changes should be
mostly transparent.
Of note, Clipper2 does not utilize the `STRICTLY_SIMPLE` flag because
clipper1 did not actually guarantee a strictly simple polygon.
Currently we ignore this flag but we may decide to run strictly-simple
operations through a second NULL union to simplify the results as much
as possible.
Additionally, the inflation options are slightly different. We cannot
choose the fallback miter. The fallback miter is always square. This
only affects the CHAMFER_ACUTE_CORNERS option in inflate, which does not
appear to be used.
Lastly, we currently utilize the 64-bit integer coordinates for
calculations. This appears to still be faster than 32-bit calculations
in Clipper1 on a modern x86 system. This may not be the case for older
systems, particularly 32-bit systems.
Seth Hillbrand
jean-pierre charras
Steven A. Falco