WOFF & WOFF2

Web Open Font Format (WOFF and WOFF2) are optimized for web delivery.

Overview

Format	Compression	Browser Support
WOFF	zlib	All modern browsers (IE 9+)
WOFF2	Brotli	Modern browsers

The format you pick is the algorithm choice — WOFF 1.0 mandates zlib, WOFF2 mandates Brotli. Each format exposes its algorithm's parameters (level, quality, transform) rather than offering a separate algorithm selector.

WOFF2 Benefits

• 30-50% smaller than TTF/OTF
• Preprocessing transforms for better compression
• Modern browser support

Converting to WOFF

# From TTF
fontisan convert font.ttf --to woff --output font.woff

# From OTF
fontisan convert font.otf --to woff --output font.woff

# Max zlib compression
fontisan convert font.ttf --to woff --output font.woff --zlib-level 9

Converting to WOFF2

# From TTF
fontisan convert font.ttf --to woff2 --output font.woff2

# From OTF
fontisan convert font.otf --to woff2 --output font.woff2

# From Type 1
fontisan convert font.pfb --to woff2 --output font.woff2

# Smallest possible output (max Brotli + table transforms)
fontisan convert font.ttf --to woff2 --output font.woff2 \
  --brotli-quality 11 --transform-tables

API Usage

options = Fontisan::ConversionOptions.from_preset(:web_optimized)
# From: :otf, To: :woff2
# generating: { brotli_quality: 11, transform_tables: true,
#              optimize_tables: true, preserve_metadata: true }

Fontisan::FontWriter.write(font, 'font.woff2', options: options)

Compression Knobs

WOFF (zlib)

Option	CLI	Range	Default
zlib_level	--zlib-level=N	0–9	6
uncompressed	--uncompressed	bool	false
compression_threshold	--compression-threshold=N	bytes	100

generating: { zlib_level: 9 }           # max zlib
generating: { uncompressed: true }      # legal per WOFF 1.0 §5.1

WOFF2 (Brotli)

Option	CLI	Range	Default
brotli_quality	--brotli-quality=N	0–11	11
transform_tables	--[no-]transform-tables	bool	false

generating: { brotli_quality: 11, transform_tables: true }

Cross-format misuse (e.g. brotli_quality on :woff) raises ArgumentError from FormatConverter.validate_options_for_target!.

Table Transforms

WOFF2 supports table transformations:

Table	Transform
glyf	Combined with loca
hmtx	Combined with hhea
CFF	De-subroutinization

options = Fontisan::ConversionOptions.new(
  to: :woff2,
  generating: { transform_tables: true }
)

Converting from WOFF

# WOFF to TTF
fontisan convert font.woff --to ttf --output font.ttf

# WOFF2 to OTF
fontisan convert font.woff2 --to otf --output font.otf

Browser Support

Browser	WOFF	WOFF2
Chrome	5+	36+
Firefox	3.6+	35+
Safari	5.1+	12+
Edge	All	14+
IE	9+	—

Best Practices

1. Use WOFF2 primarily — Best compression
2. Provide WOFF fallback — For older browsers (IE 9+)
3. Keep original — For editing
4. Preserve metadata — Unless stripping for size