Stamp each rendered facet cell item with the data-maidr-cell value its
subplot's selectors were emitted against. MUST run before any fixup pass
(or trace construction) resolves the cell-scoped selectors.
Cells are matched to grid slots in visual reading order (top-to-bottom,
left-to-right, clustered by row) when the SVG is laid out, falling back
to DOM order otherwise — Vega emits facet cell items in exactly that
reading order (the facet partition is sorted by [row, column] domain).
As a cross-check, the facet header texts (role-row-header /
role-column-header titles) are compared against the panel titles the
converter wrote into each cell's first layer; mismatches log a warning
but do not abort (navigation and audio still work; only highlighting
placement could be off).
Stamp each rendered facet cell item with the
data-maidr-cellvalue its subplot's selectors were emitted against. MUST run before any fixup pass (or trace construction) resolves the cell-scoped selectors.Cells are matched to grid slots in visual reading order (top-to-bottom, left-to-right, clustered by row) when the SVG is laid out, falling back to DOM order otherwise — Vega emits facet cell items in exactly that reading order (the facet partition is sorted by [row, column] domain).
As a cross-check, the facet header texts (
role-row-header/role-column-headertitles) are compared against the panel titles the converter wrote into each cell's first layer; mismatches log a warning but do not abort (navigation and audio still work; only highlighting placement could be off).