At a high rate, a high frequency or on noise the plots banded visibly and the bands
crawled under a pan. Three things compound to produce it, none a bug alone: a
pyramid bucket spans one to two pixel columns, Envelope emits two points per bucket
so each contributes a near-vertical hairline and a near-vertical connector, and
every one lands at a fractional x because a trace is deliberately not snapped --
so a column's brightness beats against the pixel grid, and a pan sweeps the beat.
The cure is upstream (deps/plotter, pin moved): draw_traces reduces such a window
onto the pixel grid, one snapped vertical segment per column from that column's
lowest to its highest value. One sub-pixel phase for the whole trace, so there is
nothing left to beat, and the geometry is bounded by axes.w rather than by the
buckets.
frame path: gains a columns= field, which is what separates "the segment count
collapsed because the reduction ran" from "the window got narrower". On the fast
mock at 3 kHz over 20 s: columns=1200, segments 2041/2237 over 1201 painted frames,
against columns=0, segments 10960/216093 over 263 before -- the same run at 4.6x
the frame rate, with trace ink: clean either way.
Also corrects the documented mock invocation: --batch 20000 exceeds the datagram
limit and the mock dies with Errno 90.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
