View ▸ Zoom In / Zoom Out / Actual Size (⌘+ / ⌘− / ⌘0): 75%–200% in eight
rungs, app-wide and persisted (the Show Comments precedent) — a viewing
comfort, not a property of any one board. The level travels as
BoardZoomContext in the environment, injected on BoardView alone so the
banner strip, search bar, sheets and popovers stay at the system size; the
environment is also what carries it through CardFaceView's equality gate,
which compares nothing that moves with the level. Every BoardMetrics figure
follows zoom.bodyPointSize — card and lane chrome, drag replicas and the
count badge, the resize handle, the trash column — and the drop registry
carries the ruler for event-time reads, with the autoscroller's three
reaches turning font-derived (reachSide named as the stripGap it always
equalled). Lanes still divide the window; zoom never moves the window or
its floor. The toolbar gains a catalog-only Zoom In/Out pair mirroring the
menu rows' predicate; zoom holds shut mid-drag (frozen geometry), each rung
announces itself to VoiceOver, and the render suite pins both invariants:
a rung repaints every face, a no-op Actual Size repaints nothing.
Claude-Session: https://claude.ai/code/session_014PtZdPwqZuqEDLc6wZMtEy
BoardRenderMetrics (DEBUG-only, the pathfinder's counter bag plus a
strip-body discriminator that tells a failed gate from a direct
Observation invalidation) counted at BoardView/LaneView/CardFaceView/
TrashLaneView bodies and MasonryLayout's callbacks. DragSignposts wraps
dropUpdated, retargetCards, commitDrop, and the commit-to-covering-
snapshot release pause; input latency reports honestly against
NSApp.currentEvent's mach base or labels itself base=none — no event
timestamp rides the drop path. BoardRenderPerformanceTests hosts the
real BoardView off-screen: a value-equal reload runs zero lane and zero
card bodies, a one-card edit repaints one card of 180. The lane-body
budget is <= laneCount with the headerInk chain documented and a
two-way tripwire that fails when the fix lands. Methodology in
RENDER-INSTRUMENTATION.md. Release build proves it all compiles out.
Drag-perf card a450ad09.
Claude-Session: https://claude.ai/code/session_01CqjXB7ASoWtbyoGod68k97
rzen