# Borrowed font representation tables
`font::RepresentationTable` borrows exact REPRESENTATIONS and SURFACE_GROUPS bodies. Each representation resolves its scalar surface by ordinal, derives sample depth and tight decoded cost, and uses the same duplicate-identity and size-selection rules as native `FontRepresentations`. No decoded metadata array is allocated.
Representation count comes from 16-byte records; referenced surfaces use 24-byte records. GlyphMajor logical height derives from shared glyph count, while Atlas2D keeps its stored extent. Surface index 65535 is valid when 65536 surface records are present: this index has no absent sentinel and is not a common-directory reference.
| `max_font_representations` | 64 | 1024 | Record parsing and pairwise duplicate checks |
| `max_font_glyphs` | 4096 | 1,000,000 | Shared glyph cardinality before geometry |
Count limits are enforced before per-record parsing or duplicate comparisons. Zero disables the corresponding resource. Tight decoded cost is selection metadata, not a requested allocation; `max_decoded_bytes` therefore does not reject a borrowed atlas at this step. Execution applies its output, unit and work limits independently.
```rust
use mirx::{FontRepresentation, FontRepresentationRequest, PayloadLimits,
font::{GlyphPacking, GlyphSurfaceRecord, RepresentationRecord, RepresentationTable},
image::SampleLayout};
let mut surfaces = [0; 24];
GlyphSurfaceRecord::new(SampleLayout::A4, GlyphPacking::GlyphMajor, 8, 8, 0).unwrap()
.encode_record_into(&mut surfaces).unwrap();
let mut records = [0; 16];
RepresentationRecord::new(FontRepresentation::coverage(4, 16, 64).unwrap(), 0)
.encode_record_into(&mut records).unwrap();
let table = RepresentationTable::open(&records, &surfaces, 2, &PayloadLimits::EMBEDDED).unwrap();
let selected = table.select(FontRepresentationRequest::new(16)).unwrap();
assert_eq!(selected.representation().decoded_bytes(), 64);
assert_eq!(table.get(0).unwrap().surface_index(), 0);
```
`get` and direct iterator skips resolve only the selected record in constant time. Iteration is exact-size, fused and double-ended. `select` returns an inline `FontRepresentationMatch`; neither that result nor an individual record borrows the source table. Requests, exact Coverage preference, SDF intervals and fallback retain the native selector's semantics.
The typed table supports scalar Coverage/SDF and scalar application-defined records. Other application storage remains available through raw payload preservation, without invented color semantics. Referenced surface records are checked; unused surface records are not interpreted by this representation-only view. Metrics, glyph-map offsets, storage section references, unused sections and DATA integrity remain complete-face responsibilities. Opening this table alone does not validate a FONT payload.
