FONTLAB_API_RESEARCH.md

FontLab API Research & MCP Extension Plan

Current Implementation Status

Resources (Read-only)

• fontlab://font/current - Current font info
• fontlab://font/current/glyphs - List all glyphs
• fontlab://font/info - Font metadata
• fontlab://glyph/{name} - Individual glyph details

Tools (Write operations)

• create_glyph - Create new glyph with name, unicode, width
• modify_glyph_width - Change glyph width
• transform_glyph - Scale, rotate, translate glyphs
• update_font_info - Update family name, style, version, copyright
• export_font - Export to OTF, TTF, WOFF, WOFF2, UFO
• delete_glyph - Remove glyphs

Coverage: ~10% of FontLab API capabilities

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FontLab Python API Overview

Four Main Packages

1. fontlab - High-level GUI-integrated operations
2. fontgate - Low-level font engine (technical operations)
3. typerig - Pythonic wrapper library by Vassil Kateliev
4. FL - Legacy FontLab Studio 5 compatibility

Key FontLab 8 Features

• Python 3.11 (10-60% faster than previous versions)
• 340+ preference attributes via flPreferences
• Action set execution via Python
• HTML rendering in output panel
• Special protocols: glyph:, class:, file:
• Startup script hooks: startupScript.py, initScript.py

Core API Classes

High-level (fontlab):

• flWorkspace - Application control
• flPackage - Font container
• flGlyph - Glyph operations
• flLayer - Layer operations
• flContour - Contour representation
• flNode - Node operations
• flTransform - Geometric transformations

Low-level (fontgate):

• fgFont - Font with kerning, features, axes, guides
• fgGlyph - Glyph with anchors, components, contours
• fgKerning - Kerning pairs and classes
• fgAnchor / fgAnchors - Anchor points
• fgComponent / fgComponents - Composite glyphs
• fgContour / fgContours - Bezier paths
• fgAxis / fgAxes - Variable font axes
• fgBitmap - Embedded bitmaps
• fgCoding - Character encoding/mapping
• fgColor - Color support

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Gap Analysis - Missing Features

1. Kerning & Spacing (0% coverage)

• No kerning pair management
• No kerning classes
• No auto-kerning features
• No metrics classes

2. OpenType Features (0% coverage)

• No feature code access/modification
• No glyph classes management
• No GSUB/GPOS manipulation

3. Contours & Shapes (0% coverage)

• No path/contour manipulation
• No bezier curve editing
• No node operations
• No shape operations (union, intersect, etc.)

4. Anchors (0% coverage)

• No anchor creation/editing
• No mark positioning

5. Components (0% coverage)

• No composite glyph operations
• No component transformation

6. Variable Fonts (0% coverage)

• No axes management
• No masters manipulation
• No interpolation
• No instance generation

7. Guides & Alignment (0% coverage)

• No guide creation/management
• No alignment zones

8. Hinting (0% coverage)

• No TrueType hinting
• No PostScript hints

9. Advanced Glyph Operations (5% coverage)

• Basic metrics only (LSB, RSB missing)
• No tags, notes, marks
• No glyph renaming/duplication
• No glyph searching by unicode

10. Layers (0% coverage)

• No layer management
• No multi-master layer operations

11. Font-level Operations (10% coverage)

• Basic info only
• No font validation
• No glyph sorting/reordering
• No font comparison
• No batch operations

12. Color Fonts (0% coverage)

• No color layer management
• No SVG/COLR/CBDT support

13. Bitmaps (0% coverage)

• No bitmap glyph support

14. Import/Export (20% coverage)

• Basic export only
• No import functionality
• No format conversion options
• No UFO read/write

15. Application Control (0% coverage)

• No viewport manipulation
• No UI interaction
• No preferences access
• No action set execution

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Proposed Extensions by Category

A. KERNING & METRICS (High Value)

Resources:

• fontlab://font/kerning - Get all kerning pairs
• fontlab://font/kerning/classes - Get kerning classes
• fontlab://font/metrics-classes - Get metrics classes

Tools:

• set_kerning_pair - Set kerning between two glyphs
• remove_kerning_pair - Remove kerning pair
• create_kerning_class - Create kerning class
• auto_kern - Auto-generate kerning
• import_kerning - Import kerning from file
• export_kerning - Export kerning data
• set_metrics_class - Create/update metrics class
• set_glyph_sidebearings - Set left/right sidebearings
• auto_metrics - Auto-calculate metrics

B. CONTOURS & SHAPES (High Value)

Resources:

• fontlab://glyph/{name}/contours - Get contour data
• fontlab://glyph/{name}/paths - Get path data with nodes

Tools:

• add_contour - Add contour to glyph from path data
• remove_contour - Remove contour by index
• modify_contour - Modify nodes in contour
• reverse_contour - Reverse contour direction
• simplify_contour - Simplify/optimize paths
• union_shapes - Boolean union
• intersect_shapes - Boolean intersection
• subtract_shapes - Boolean subtraction
• outline_stroke - Convert stroke to outline
• add_node - Add node to contour
• remove_node - Remove node from contour
• convert_node_type - Change curve/corner type
• align_nodes - Align selected nodes
• distribute_nodes - Distribute nodes evenly

C. ANCHORS (Medium Value)

Resources:

• fontlab://glyph/{name}/anchors - Get anchor positions

Tools:

• add_anchor - Add anchor to glyph
• remove_anchor - Remove anchor
• move_anchor - Reposition anchor
• auto_anchor - Auto-position anchors
• generate_mark_feature - Generate mark/mkmk features

D. COMPONENTS (High Value)

Resources:

• fontlab://glyph/{name}/components - Get component info

Tools:

• add_component - Add component reference
• remove_component - Remove component
• decompose_glyph - Break components to outlines
• transform_component - Transform specific component
• auto_build_composites - Build composite glyphs

E. OPENTYPE FEATURES (High Value)

Resources:

• fontlab://font/features - Get all feature code
• fontlab://font/features/{tag} - Get specific feature
• fontlab://font/classes - Get glyph classes

Tools:

• set_feature_code - Set OpenType feature code
• compile_features - Compile and validate features
• create_glyph_class - Create glyph class
• remove_glyph_class - Remove glyph class
• generate_feature - Auto-generate feature (kern, mark, liga, etc.)

F. VARIABLE FONTS (Medium-High Value)

Resources:

• fontlab://font/axes - Get variation axes
• fontlab://font/masters - Get font masters
• fontlab://font/instances - Get defined instances

Tools:

• add_axis - Add variation axis
• remove_axis - Remove axis
• add_master - Add font master
• set_master_location - Position master in design space
• generate_instance - Generate font instance
• interpolate_glyphs - Interpolate between masters
• create_variable_font - Export variable font

G. LAYERS (Medium Value)

Resources:

• fontlab://glyph/{name}/layers - Get layer info

Tools:

• add_layer - Add layer to glyph
• remove_layer - Remove layer
• copy_layer - Copy layer contents
• merge_layers - Merge layers

H. GUIDES & ZONES (Low-Medium Value)

Resources:

• fontlab://font/guides - Get global guides
• fontlab://font/zones - Get alignment zones

Tools:

• add_guide - Add guide
• remove_guide - Remove guide
• add_zone - Add alignment zone
• add_stem - Add stem hint

I. ADVANCED GLYPH OPERATIONS (Medium Value)

Resources:

• fontlab://glyphs/search - Search glyphs (by unicode, name pattern, etc.)
• fontlab://glyph/{name}/metadata - Get tags, notes, marks

Tools:

• rename_glyph - Rename glyph
• duplicate_glyph - Duplicate glyph
• copy_glyph_to_font - Copy between fonts
• set_glyph_unicode - Set/change unicode
• set_glyph_note - Set note
• set_glyph_tags - Set tags
• set_glyph_mark - Set color mark
• find_replace_glyph - Find and replace by pattern
• sort_glyphs - Reorder glyphs

J. FONT VALIDATION & ANALYSIS (Medium Value)

Resources:

• fontlab://font/validation - Get validation errors
• fontlab://font/statistics - Get font statistics

Tools:

• validate_font - Run font validation
• find_overlaps - Find overlapping paths
• find_open_paths - Find open contours
• find_wrong_directions - Check path directions
• auto_fix_contours - Auto-fix common issues
• analyze_spacing - Analyze glyph spacing

K. IMPORT/EXPORT (Medium Value)

Tools:

• import_font - Import font file
• import_glyphs - Import specific glyphs
• import_ufo - Import UFO
• export_ufo - Export UFO
• export_glif - Export glyphs as GLIF
• batch_export - Export multiple formats

L. COLOR FONTS (Low-Medium Value)

Resources:

• fontlab://glyph/{name}/color-layers - Get color layers

Tools:

• add_color_layer - Add color layer
• set_layer_color - Set layer color
• import_svg - Import SVG to glyph
• export_svg - Export glyph as SVG

M. APPLICATION CONTROL (Medium Value)

Resources:

• fontlab://workspace/preferences - Get preferences
• fontlab://workspace/viewport - Get viewport state

Tools:

• update_viewport - Refresh view
• set_preference - Change preference
• run_action_set - Execute action set
• execute_macro - Run macro/script
• open_font - Open font file
• close_font - Close font
• save_font - Save current font

N. BATCH OPERATIONS (High Value for Automation)

Tools:

• batch_transform - Transform multiple glyphs
• batch_rename - Rename glyphs by pattern
• batch_unicode - Assign unicodes by pattern
• batch_create_glyphs - Create multiple glyphs
• batch_delete_glyphs - Delete multiple glyphs
• apply_to_selection - Apply operation to selected glyphs

O. HINTING (Low Value - Specialized)

Tools:

• auto_hint_ps - Auto-hint PostScript
• auto_hint_tt - Auto-hint TrueType
• clear_hints - Remove all hints

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Implementation Roadmap

PHASE 1: CORE EXPANSION (Highest Impact)

Priority: Immediate - Covers most common use cases

1. Contours & Shapes (Category B)

   • Path data access and manipulation
   • Boolean operations
   • Node operations
   • ~15 tools

2. Kerning & Metrics (Category A)

   • Kerning pair management
   • Kerning classes
   • Metrics classes
   • ~9 tools

3. Components (Category D)

   • Component operations
   • Composite glyph building
   • ~5 tools

4. Advanced Glyph Operations (Category I)

   • Glyph search, rename, duplicate
   • Metadata (tags, notes, marks)
   • ~9 tools

Estimated: ~38 new tools + 8 resources

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PHASE 2: PROFESSIONAL FEATURES (High Value)

Priority: Next - Enables professional font production

5. OpenType Features (Category E)

   • Feature code management
   • Glyph classes
   • Feature compilation
   • ~6 tools

6. Variable Fonts (Category F)

   • Axes and masters
   • Interpolation
   • Instance generation
   • ~7 tools

7. Font Validation & Analysis (Category J)

   • Validation
   • Auto-fix tools
   • ~6 tools

8. Import/Export (Category K)

   • Enhanced import/export
   • UFO support
   • ~6 tools

Estimated: ~25 new tools + 10 resources

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PHASE 3: SPECIALIZED FEATURES (Medium Value)

Priority: Optional - Niche but valuable

9. Anchors (Category C)

   • Anchor management
   • Mark feature generation
   • ~5 tools

10. Layers (Category G)

    • Layer operations
    • ~4 tools

11. Guides & Zones (Category H)

    • Guide management
    • Alignment zones
    • ~4 tools

12. Application Control (Category M)

    • Workspace control
    • Preferences
    • Action sets
    • ~7 tools

Estimated: ~20 new tools + 6 resources

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PHASE 4: AUTOMATION & SPECIALTY (Lower Priority)

Priority: Future - Automation and specialized workflows

13. Batch Operations (Category N)

    • Bulk transformations
    • Pattern-based operations
    • ~6 tools

14. Color Fonts (Category L)

    • Color layer support
    • SVG import/export
    • ~4 tools

15. Hinting (Category O)

    • Auto-hinting
    • ~3 tools

Estimated: ~13 new tools + 2 resources

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Quick Wins (Recommended Starting Point)

These provide immediate value with moderate effort:

1. Glyph search/filtering - Very useful for LLMs

   • fontlab://glyphs/search?pattern=A*
   • fontlab://glyphs/by-unicode/{codepoint}

2. Glyph rename/duplicate - Common operations

   • rename_glyph(old_name, new_name)
   • duplicate_glyph(name, new_name)

3. LSB/RSB adjustment - Basic metrics control

   • set_sidebearings(name, lsb, rsb)

4. Glyph metadata (tags, notes) - Organization

   • set_glyph_note(name, note)
   • set_glyph_tags(name, tags)

5. Basic kerning pairs - Essential typography

   • set_kerning_pair(left, right, value)
   • fontlab://font/kerning

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Total Scope Estimate

Features Identified:

• ~96 new tools across all phases
• ~26 new resources for data access
• Current: 6 tools + 4 resources
• Full coverage: 102 tools + 30 resources

Development Effort:

• Phase 1: 3-4 weeks (high impact)
• Phase 2: 2-3 weeks (professional features)
• Phase 3: 2-3 weeks (specialized)
• Phase 4: 1-2 weeks (automation)

Total: ~8-12 weeks for complete API coverage

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Architecture Recommendations

Improvements to Consider

1. Caching Layer - Cache font info to reduce bridge calls
2. Batch Mode - Bundle multiple operations into single script execution
3. Event Hooks - Listen for font changes in FontLab
4. Better Error Handling - Propagate FontLab errors with context
5. Streaming Support - For large data (e.g., all contour paths)
6. Async Improvements - Non-blocking operations where possible
7. Type Validation - Validate parameters before sending to FontLab
8. Result Formatting - Use FontLab 8's HTML output for rich responses

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Useful Resources

Official Documentation

• Main API: https://fontlabcom.github.io/fontlab-python-docs/
• FontLab 8 scripting: https://help.fontlab.com/fontlab/8/whats-new/whats-new-12-scripts-extensions/
• Extend FontLab: https://extend.fontlab.com/

Key Classes to Study

• flWorkspace - Application control
• flPackage - Font container
• flGlyph - Glyph operations
• flLayer - Layer operations
• fgFont - Low-level font operations
• fgKerning - Kerning management
• fgContour - Path/contour operations
• fgComponent - Component operations
• fgAnchor - Anchor management

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Next Actions

1. ✅ Save this research document
2. ⬜ Start with "Quick Wins" implementation
3. ⬜ Test FontLab bridge with actual FontLab installation
4. ⬜ Implement Phase 1 features iteratively
5. ⬜ Add comprehensive error handling
6. ⬜ Create test suite for FontLab integration
7. ⬜ Document each new tool/resource as implemented