Implements Task 2 of the LayoutDesc Importer (Plan 1 — vitals conformance).
- ElementInfo POCO: GL-free/dat-free snapshot of a resolved layout element.
Shape matches the plan spec exactly (Id, Type as uint, X/Y/Width/Height as
float, raw Left/Top/Right/Bottom uint edge flags, ReadOrder, FontDid, StateMedia
dict, Children list). Tasks 3–6 depend on this shape.
- ElementReader.ToAnchors(uint,uint,uint,uint): maps dat edge-flag values
(0=none, 1=near-pin, 2=far-pin, 3=floating-center, 4=stretch) to AnchorEdges
bit flags. Corrects the plan's stale assumption that value 4 was the only anchor
trigger; the verified format doc §4 shows 1→Left/Top, 2→Right/Bottom, 4→both.
All-zero falls back to Left|Top (default pin top-left).
- ElementReader.Merge(base_, derived): inheritance merge mirroring BaseElement/
BaseLayoutId. Derived scalars win when non-zero; position/edge-flags/ReadOrder
always from derived; StateMedia merged (base defaults, derived overrides);
Children from derived only.
TDD: tests written first (9 tests covering ToAnchors near-pin/far-pin/stretch/
zero/value-3, Merge scalar override/font inheritance/StateMedia merge/children).
All 9 pass; dotnet build 0 errors 0 warnings.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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