The Move command grabbed footprints from the nearest grid point rather
than the footprint anchor. This was caused by the reference point being
grid-aligned at drag start (commit 89be3fd390), which was a workaround
for fractional-nanometer positioning errors with non-page display origin.
Fix the root cause instead: AlignGrid(VECTOR2I, VECTOR2D, VECTOR2D)
relied on implicit VECTOR2D->VECTOR2I truncation to pass grid parameters
to computeNearest. For grid sizes that aren't exact in IEEE 754 double
(e.g., 0.254mm = 10 mil becomes 253999.999... instead of 254000), the
truncation produces incorrect grid sizes. Use KiROUND for the conversion
so all grid operations produce exact grid multiples.
With AlignGrid returning correct positions, the move tool no longer needs
to grid-align its reference point. Restore the anchor-based grab and the
GetMoveWarpsCursor() preference that 89be3fd390 removed.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/23308
Seth Hillbrand
42928c8b2f