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Decision 0027 - Catalog low-information specimen rendering policy

Date: 04/04/2026 Status: Accepted

Context

Catalog generation now renders many more families from the persisted inventory than the historical TeX-side bookkeeping model assumed.

That broader coverage exposes two distinct classes of low-value output:

  • text fonts whose stored primary specimen is technically valid but too short to be useful in the catalog
  • specialized fonts such as icon or symbol faces whose metadata does not justify pretending they are normal text fonts

The catalog renderer therefore needs a deterministic policy for handling low-information primary specimens without misrepresenting the font.

This is no longer an incidental implementation detail because the rule affects the visible PDF artifact and the catalog contract seen by users.

Decision

The catalog renderer adopts the following low-information specimen policy:

1. Keep useful stored primary specimens unchanged

If the persisted primary specimen is already above the renderer usefulness threshold, render it unchanged.

2. Prefer curated script specimens for writing fonts

If the persisted primary specimen is too short to be useful and the font still behaves like a text font, try the ontology-backed predefined specimen for the primary script and filter it through the font cmap.

If that curated specimen survives the existing renderer threshold, use it instead of the stored low-information specimen.

3. Do not fabricate text for specialized fonts

If the persisted primary specimen is too short to be useful, no curated primary-script replacement survives, and the font behaves like a specialized non-text face, suppress the text specimen and render a compact specialized-font notice instead.

The current specialized-font classifier is intentionally conservative:

  • low-information primary specimen
  • no declared or inferred languages
  • specimen strategy indicates cmap-driven or validated fallback output

4. Keep the rule renderer-local

This policy changes catalog presentation only. It does not modify the persisted inventory specimen-selection pipeline or schema.

Consequences

Positive

  • writing fonts get more informative catalog specimens when curated script samples are available
  • specialized symbol-like fonts are no longer misrepresented as if they had meaningful text coverage
  • output remains deterministic because both the classifier and curated fallback path are metadata- and cmap-driven

Negative

  • some fonts now render a specialized notice instead of a specimen block, which changes the visible PDF contract
  • specialized-font classification is conservative and may still require future refinement as more edge cases are observed
  • Issue #70 — feat(catalog): gate TOC and clickable navigation behind a flag
  • Issue #59 — Create selective archives
  • ADR 0022 — Fontshow — Specimen Inference Inputs Matrix v1.0
  • ADR 0026 — Schema v1.3 nested inventory structure and LaTeX validation metadata