Migrate from fonttools (Python)

This guide helps you migrate from Python's fonttools library to Fontisan.

Overview

fonttools (Python)	Fontisan (Ruby)
Python required	Pure Ruby
Native extensions	Pure Ruby
No validation	Built-in validation
Partial Type 1	Full Type 1 support

Quick Reference

Loading Fonts

# fonttools
from fontTools.ttLib import TTFont
font = TTFont('font.ttf')

# Fontisan
font = Fontisan::FontLoader.load('font.ttf')

Saving Fonts

# fonttools
font.save('output.ttf')

# Fontisan
Fontisan::FontWriter.write(font, 'output.ttf')

TTX Export

# fonttools
ttx font.ttf

# Fontisan
fontisan export font.ttf --format ttx --output font.ttx

Command Equivalents

ttx

fonttools	Fontisan
ttx font.ttf	fontisan export font.ttf --format ttx
ttx -t name font.ttf	fontisan export font.ttf --format ttx --tables name
ttx -o output.ttx font.ttf	fontisan export font.ttf --format ttx --output output.ttx

fonttools subset

fonttools	Fontisan
fonttools subset font.ttf --text="ABC"	fontisan subset font.ttf --chars "ABC"
fonttools subset font.ttf --unicodes="U+0041"	fontisan subset font.ttf --unicodes "U+0041"
fonttools subset font.ttf --output-file=out.ttf	fontisan subset font.ttf --output out.ttf

API Migration

Access Tables

# fonttools
name_table = font['name']
family = name_table.getBestFamilyName()

# Fontisan
name_table = font.tables['name']
family = name_table.family_name

Get Glyph Count

# fonttools
num_glyphs = font['maxp'].numGlyphs

# Fontisan
num_glyphs = font.tables['maxp'].num_glyphs

Iterate Glyphs

# fonttools
for glyph_name in font.getGlyphOrder():
    print(glyph_name)

# Fontisan
font.glyphs.each_with_index do |glyph, id|
  puts font.glyph_name(id)
end

Variable Fonts

# fonttools
axes = font['fvar'].axes
for axis in axes:
    print(axis.axisTag, axis.minValue, axis.maxValue)

# Fontisan
fvar = font.tables['fvar']
fvar.axes.each do |axis|
  puts "#{axis.tag}: #{axis.min_value} - #{axis.max_value}"
end

Generate Instance

# fonttools
from fontTools.varLib.instancer import instantiateVariableFont
instance = instantiateVariableFont(font, {'wght': 700})

# Fontisan
writer = Fontisan::Variation::InstanceWriter.new(font)
instance = writer.generate_instance(wght: 700)

Feature Comparison

Feature	fonttools	Fontisan
Pure Ruby	❌	✅
Python-free	❌	✅
TTF/OTF support	✅	✅
WOFF/WOFF2	✅	✅
Type 1 support	Partial	✅
Variable fonts	✅	✅
Font validation	❌	✅
Hint conversion	❌	✅
Collections	✅	✅
UFO format	✅	Planned
FEA parsing	✅	❌
Designspace	✅	❌

Advantages of Fontisan

Pure Ruby

• No Python installation required
• No native extension compilation
• Works in Ruby-only environments
• Easy deployment

Built-in Validation

# Fontisan has validation built-in
result = Fontisan.validate('font.ttf', profile: :production)
puts result.valid?

Bidirectional Hint Conversion

# Convert hints between TrueType and PostScript
fontisan convert font.ttf --to otf --hinting-mode preserve

Type 1 Support

# Full Type 1 support including conversion
fontisan convert font.pfb --to otf --output font.otf

Migration Checklist

1. [ ] Install Fontisan: gem install fontisan
2. [ ] Replace from fontTools.ttLib import TTFont with require 'fontisan'
3. [ ] Replace TTFont(path) with Fontisan::FontLoader.load(path)
4. [ ] Replace font.save(path) with Fontisan::FontWriter.write(font, path)
5. [ ] Update table access from font['name'] to font.tables['name']
6. [ ] Test your workflow

Getting Help

• Fontisan Guide
• API Reference
• GitHub Issues