validate-collection

Validate the structural integrity of a TTC / OTC / dfont collection: face count, per-face glyph cap, and optional cmap-union size.

This is a collection-level counterpart to validate, which runs profile-based per-face quality checks (OpenType compliance, hint validity, etc.). Use validate-collection when you care about the shape of the collection (number of faces, glyph-cap overflows, codepoint coverage) rather than per-face quality.

Quick Reference

fontisan validate-collection <path> [options]

The command exits 0 when every requested check passes and 1 when any check fails. With no options, only the per-face glyph cap is checked (default 65,535).

Options

Option	Default	Description
--expected-faces N	(none)	Require exactly N faces in the collection.
--max-glyphs N	65535	Per-face glyph cap (maxp.numGlyphs). Faces over this cap fail.
--expected-cmap-union N	(none)	Require the union of cmap codepoints across all faces to be at least N.

Examples

# Glyph-cap-only check (default behaviour, no optional checks)
fontisan validate-collection family.ttc

# Require exactly 5 faces
fontisan validate-collection family.ttc --expected-faces 5

# Tighter per-face glyph cap
fontisan validate-collection family.ttc --max-glyphs 60000

# Require at least 100,000 codepoints covered across all faces
fontisan validate-collection family.ttc --expected-cmap-union 100000

Sample output

face 0:    3541 glyphs ✓
face 1:   21048 glyphs ✓
face 2:     991 glyphs ✓
all 3 faces within 65535-glyph cap ✓
face_count: ✓
cmap union: 24580 cps ✓

When a check fails, the marker becomes ✗ and a message is printed in parentheses; the exit code is 1.

Programmatic access

The command is a thin wrapper around Fontisan::Collection::Reader, which exposes per-face metadata directly:

reader = Fontisan::Collection::Reader.open("family.ttc")
reader.face_count                  # => 3
reader.stats.map(&:glyph_count)    # => [3541, 21048, 991]
reader.cmap_union.size             # => 24580

Use the command-class directly when you want structured results without stdout:

cmd = Fontisan::Commands::ValidateCollectionCommand.new(
  input: "family.ttc",
  expected_faces: 3,
)
exit_code = cmd.run           # 0 or 1
cmd.checks                    # => [#<Check name=:face_count passed=true ...>, ...]

See also

• validate — per-face profile-based checks (OpenType compliance, hint validity, etc.)
• pack / unpack — create and extract collections