Two separable findings from the live A/B (real driver): (1) the
original zero-ring report was a viewport-framing crop — the ring
fired all along at screen (1755,-191), above the frame under the
COVER fit; recentering via set_view proved the path live. (2) The
real bug once in-frame: at Quarter fit zoom the compensated ring
radius (5.0/7.5=0.667 canvas) fell below the floored stroke (1.0
canvas) and draw_arc's stroke filled its own hole — a solid blob,
not a ring. Bracket: 1x stroke=blob, 1.5x=hollow recovers, 2x=clean.
Fix: zoom_compensated_ring_radius() floors the radius at 2x the
paired stroke, wired through _zs_ring_radius() for both ring and
halo arcs; verified live producing a clean hollow double-ring. The
third member of the Godot sub-canvas-unit rasterizer family (width
floor, stroke-vs-width sites, now radius-vs-stroke) — all recorded
for the T-1176 render-mechanism discussion. 10 pin tests in the
stroke-width suite; revert-verified (floor drop -> named failures);
full client suite 3956/3956; gdlint clean.
Tickets: T-1170
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
jpmschweitzerandClaude Fable 5
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