Specimen Press

Specimen Press inspects TrueType fonts and turns glyph outlines into readable SVG specimen sheets.

It exposes one Swift library and one command-line tool.

Value

Use it when a font needs a compact, repeatable inspection artifact.

The output shows glyph coverage, font metrics, baselines, and decoded outline paths.

The bundled fixture makes the demo and tests run without network access or secrets.

Capabilities

• Parse head, cmap, hmtx, and glyf tables.
• Read loca, maxp, hhea, and optional name data.
• Decode simple and composite glyph outlines.
• Report metrics and Unicode coverage as FontSummary.
• Render an SVG specimen sheet for a TrueType font.
• Draw sample text, metric lines, and an uppercase glyph grid.

Architecture

BinaryReader reads big-endian values with bounds checks.

TrueTypeFont validates the table directory and coordinates table parsing.

GlyphDecoder expands simple contours and composite components.

SpecimenRenderer maps outlines into a stable SVG layout.

The CLI keeps file access and output formatting outside the library.

Setup

Install Swift 5.9 or newer.

Clone the repository.

Run the bundled demo.

swift run specimen-press demo --output specimen.svg

Open specimen.svg in a browser or vector editor.

Inspect any TrueType font.

swift run specimen-press inspect /path/to/font.ttf

Render a custom sheet.

swift run specimen-press render /path/to/font.ttf   --output specimen.svg   --sample "A SHORT FONT SAMPLE"

Run tests and a release build.

swift test
swift build -c release

Sample output

The bundled fixture reports stable values.

{
  "familyName" : "Specimen Press",
  "mappedCodePointCount" : 27,
  "metrics" : {
    "ascender" : 800,
    "descender" : -200,
    "lineGap" : 200,
    "numberOfGlyphs" : 28,
    "numberOfHorizontalMetrics" : 28,
    "unitsPerEm" : 1000
  }
}

The demo writes one SVG file.

Wrote specimen.svg

Tests

Tests assert fixture metrics, coverage ranges, glyph outlines, SVG labels, and malformed input handling.

Local status: not run because Swift is unavailable in the supplied Windows environment.

CI runs swift test, a release build, and the bundled demo on macOS.

Limitations

• The first release supports TrueType outlines in glyf.
• It does not parse CFF or CFF2 outlines.
• It reads cmap formats 4 and 12.
• It does not execute TrueType hinting instructions.
• It renders uppercase A-Z cells and uses glyph zero for missing sample characters.
• It inspects one font file at a time.
• It does not subset, edit, or write font files.

Roadmap

1. Add CFF and CFF2 outline inspection.
2. Add kerning and variable-font axis summaries.
3. Add optional JSON and SVG snapshot fixtures.
4. Add contour winding diagnostics.

License

The library and CLI use the MIT License.

The bundled fixture uses the CC0 1.0 Universal dedication in FONT-LICENSE.txt.