New EXPERIMENTAL dialog option (default off): after the solve, copper
whose |J| is below a threshold (default 10% of the mean |J| over all
solved copper cells - mean, not max, since contact-corner spikes would
dwarf a max-relative threshold) is vectorized into filled graphic
polygons on TRIM_LAYERS (User.5..User.8, configurable), one polygon
per region so Edit > Convert can turn one into a rule area by hand.
Areas are printed and the polygons saved to low_current_copper.json.
The mask -> polygon step is the 0.5 contour of the binary field via
contourpy (already in every venv as matplotlib dependency), padded so
regions touching the raster edge close, simplified with
Douglas-Peucker at 0.4 cells: staircase bevels collapse, one-cell-wide
strips survive. Specks under TRIM_MIN_AREA_MM2 are dropped.
Explicitly a suggestion, not a safe cut list (docstring, dialog and
README all say so): copper carries little current BECAUSE the rest
carries it, so removal redistributes |J| - the constant-density
optimizer that iterates this to convergence is future work.
board_io: the create/delete-with-status-surfaced helpers are now
generic (_create_items_checked / _remove_items_checked) and shared
between reference-image overlays and trim polygons.
Tested on the dev stack (3.13) and the Python 3.9 mac-stack venv, 148
passed each; contourpy 1.3.x has identical API on both.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
