ARCADIA-Studio/harness/experiments/wrapped-label-20261001/change-summary.md

E/F measured-label experiment implementation handoff

Local uncommitted implementation against 6ea7518e7be5b5f17d5fbc5d667da8b388058af4. No compiler, GUI, Gitea, commit or push run by this worker. Root owns all gates. rustfmt --edition 2024 --config skip_children=true completed for the six explicitly owned/authorized Rust files. This establishes formatting only.

Changed implementation

• New private crates/oa-desktop/src/diagram/label_layout_experiment.rs contains read-once external E/F/Baseline profile, one-target identity guards, measured typography cache, shared Layout, fixed placements, collision guards, Canvas line records, explicit SVG line export and five focused tests.
• diagram.rs: Scene stores the shared Layout, profile and font-system version; both ordinary and work-preview scenes apply it before geometry consumers. Existing cache additionally keys profile/font version. Drawing and SVG consume the same ordered line positions. Derived target label bounds feed existing hit and route-drag start code. The private adapter applies to already-routed data.
• Parent-authorized thin calls: app.rs Fit, diagram_usage.rs whole/edge bounds, and diagram/work_drag.rs dirty-input shield. No second routing call introduced.
• diagram/attachment_tests.rs: existing manual Scene literal gains default fields.
• Parent supplied the pinned harness/experiments/wrapped-label-20261001/fixture/eight-card.json; it is referenced with include_bytes, not rewritten by this worker.

No changes to core, schema, source formats, canonical label.text/Name, Project, port/card/path state, or B's cue. The fixture and diagram are identified exactly; other labels return untouched. Baseline returns the complete routed value unchanged. Automatic guard failure leaves baseline rather than painting an invalid narrower shape over an old hitbox. Nested/collapsed scenes are excluded from this witness.

Measurement and scope

Pinned Iced 0.14 graphics Paragraph is accessible through iced::advanced::graphics::text::Paragraph; the same implementation is used by Canvas Text. Each fixed line is shaped at font 13 with absolute line height 16, Basic ASCII shaping and no wrap. Width comes from Paragraph min_width; baseline and resolved face family come from actual cosmic-text runs. A single face per line is required; mixed fallback or unsupported metrics reject the trial. Cached measurements are keyed by profile and Iced font-system version; ordinary hover, selection and camera changes reuse the entire Scene. No character-count width heuristic is used.

SVG writes explicit per-line x and shaped baseline y with the resolved family, not browser wrapping or generic sans-serif. It does not embed the font: native export rendering and font availability on another machine remain a validation boundary, not proven glyph parity. Tests compare generated text/geometry records, not raster output or browser appearance.

Automatic E permits exactly one straight own segment crossing both padded sides; all foreign strokes, cards and labels (including association-end labels) are excluded. Automatic F clears all strokes. Guards use measured boxes, card margin 12, other-label margin 4 and stroke margin 3. Fixed F's own-is-closer width margin is explicitly asserted by its fixture test rather than accepted as a general placement scoring rule.

Authored target labels keep the externally selected line shape and honor actual fraction/offset. They deliberately retain that shape when a user moves into a collision, reporting Layout.clear=false; silently unwrapping/resetting would violate the trial boundary. Conservative whole-scene bounds retain prior bounds and include moved authored boxes. No ordinary save/reopen formatting contract, general typesetter, placement winner, or production policy is claimed.

Parent gates

Suggested targeted test selector:

cargo test --locked -p oa-desktop label_layout_experiment -- --test-threads=1 --nocapture

Five tests cover full unchanged baseline and all 12 point arrays/other labels, actual measured dimensions and guard result, matching Canvas/SVG/picking/focus geometry records, foreign-stroke/card rejection without mutation, authored fraction/offset/shape retention during real route-preview construction, and actual Scene/measurement cache reuse plus profile/revision invalidation. The first test prints measured line/family/bounds records for parent capture.

Compilation, strict lint, fixture guard feasibility on this font installation, native rendering, actual edit lifecycle, performance, independent fresh-reader trial, and integration/publication remain pending. Preserve first failures and revise at the responsible layer; no successful test/native outcome is asserted.

Captured failure and responsible preview-baseline correction

Parent observed initial source d8ccd6ed49adac799c02a3c52cb9e431214a4963 fail compilation because the test EdgeRoute literal omitted its attachment fields. The first compiler log remains .local/wrapped-label-tests-first.log. At regression source ebb6a9980b11c4d4df2f7e413c6b135a337f6f6d, parent observed five tests passing and the added different-edge preview regression failing: guard rejection cleared Layout, but target geometry retained wrapped E bounds (119.174805 x 40) instead of core one-line bounds (233 x 24). Parent's measured F was 89.18213 x 56; both used Segoe UI. These are parent-reported executed results, not worker-executed gates. Failed transition log is retained at .local/wrapped-label-regression-first.log.

Correction, now local and frozen for parent compilation: Scene retains a core_routed Arc before the experiment modifies derived presentation. Both ordinary and allocation-work-preview constructors store that raw Arc; Baseline shares it with routed without copying. begin_route_with_profile captures core_routed, so core preview freezes raw one-line labels and a refused wrapper leaves a complete valid fallback. No guards, measured dimensions, route/path scoring or failing-regression assertions were changed. The existing authored preview test setup now uses the same raw baseline contract; existing cache test also checks Baseline's Arc identity. The one manual Scene literal was updated.

No additional compiler/native execution by this worker. Explicit-file rustfmt and git diff --check passed. Parent rerun of all six tests and broader gates is pending at this correction checkpoint.