E01 · F01 · SP-001 — Research for the remaining stories of F01
Find, read and record the sources of EN-005, EN-006, EN-007, US-003 and VAL-001 before implementing them (ADR-0020, added after F01 was refined).
Acceptance criteria
- Given EN-005 to VAL-001, when the spike ends, then every formula and behavior they need has a verified
REF-*, aDERIV-*or an open research request. - Given the sources found, when the spike ends, then the stories' criteria and tasks cite them, and research note 0003 records what was found and what remains open.
Questions
Inventory (T1): what each remaining story needs, and where it comes from.
| Story | Needs | Source |
|---|---|---|
| EN-005 | edge length L = ‖e‖ | Euclidean norm (REF-MATHWORLD-VECTOR-NORM) |
| EN-005 | factor per edge f = 1 if S ≤ L, else L / S (tested before dividing: L = S = 0 on a zero-length edge), per vertex g = min(fᵢ₋₁, fᵢ) | DERIV-local-radius-clamp, principle of REF-CSS-BR §4.5 |
| EN-005 | setback at a vertex | DERIV-fillet-setback (EN-004) |
| EN-006 | unit direction of an edge; zero-length edges (size 0, Q15) | REF-MATHWORLD-UNIT-VECTOR; zero vector handled explicitly |
| EN-006 | tangent points, arc center, turning direction of the arc | to derive: DERIV-fillet-arc (Euclid III.18, IV.4; rotation by a quarter turn REF-MATHWORLD-ROTATION-MATRIX) |
| EN-006 | segment of zero length after clamping (circle) | EPSILON = 1e-9 (Q10, ADR-0003) |
| EN-007 | A rx ry x-axis-rotation large-arc-flag sweep-flag x y, flag grammar | REF-SVG2-PATHS §9.3.8, §9.3.9 |
| EN-007 | meaning of the flags; zero radius; radii too small | REF-SVG2-IMPLNOTE B.2.1, B.2.5 |
| EN-007 | "positive-angle" direction on screen | REF-SVG2-COORDS §8.4 (y down) |
| US-003 | requested vs effective radius, display | docs/domain/shapes.md §2 (Q8, settled) — no open business point |
| VAL-001 | replays the feature's criteria | no new source: the criteria and the check tables above |
Tasks
One task = one commit, referenced as SP-001.Tn.