This bug was seen only with some shapes, not all, and only for layers having a negative margin.
Fixes: lp:1831941
https://bugs.launchpad.net/kicad/+bug/
This places the arc approximation setting in the kicad_pcb file and uses
it for all parts of the board rendering where arcs are converted to
segments. This allows the user to customize their speed vs. accuracy
tradeoff. The default setting of maximum error of 0.005mm is acceptable
for small boards on moderate systems.
This corrects an issue with fill segments-per-circle and moves the error
to segmetns calculation down in a number of functions to expose the
single value for approximation
This removes the remaining hard-coded segments counts and replaces them
with the relative error calculation where the segments per arc is
determined by the maximum error we allow (smaller arcs = fewer segments)
Where we can get away with lower segment counts (localizing an anchor),
we keep the low-def 16 segment count. Intermediate values and values
that are visible to the user are set to high definition. Most are
simply hints to the inflation correction but where they show, the user
show see smooth lines.