DEPRECATED

merge_font

Short utilities for merging and polishing TrueType/OpenType fonts used by the build tasks.

Requirements

• Python packages: foundrytools.

Usage

From Python build tasks:

uv run task.py merge

If config file not exists, it will be auto created. Example:

{
  "family_name": "Maple Mono",
  "output_dir": "./fonts",
  "line_height": [850, -200],
  "instances": {
    "regular": [
      "base_font.ttf",
      {
        "enable": true,
        "path": "override_font.ttf",
        "unicode_range": ["U+0030-0039", "U+2190-2199"],
        "width_scale": 1.06,
        "axes": {"wght": 400, "wdth": 100}
      }
    ],
    "bold": [
      "/path/to/static/font.ttf",
      {
        "path": "/path/to/variable/font.ttf",
        "axes": {"wght": 700, "wdth": 110},
        "width_scale": 0.98,
        "unicode_range": ["U+4E00-9FFF"]
      },
      {
        "enable": false,
        "path": "disabled_font.ttf"
      }
    ]
  }
}

Configuration Options

• family_name: The family name of the resulting font family (required)
• output_dir: Output directory for generated fonts (required)
• line_height: Line height config, formats:
  • Scaling factor (number, e.g. 1.02)
  • Simple [top, bottom] (e.g. [950, -200])
  • Full config { "top": num, "bottom": num, "safe_top": num, "safe_bottom": num }
• instances: Object mapping style names to font configuration arrays

Each instance style contains an array where:

• First element is the base font (string path or object with axes)
• Subsequent elements are override fonts with configuration options

Override Font Configuration

Each override font supports:

• path: Path to the override font file (required)
• enable: Enable/disable this override (default: true)
• unicode_range: Array of Unicode ranges to include (e.g., ["U+0030-0039"] for digits)
• width_scale: Scale factor for glyph widths (e.g., 1.06 makes 6% wider)
• axes: Variable font axis values for instantiation

Features

• Multiple Overrides: Merge base font with unlimited override fonts
• Unicode Range Filtering: Subset overrides to specific Unicode ranges
• Width Scaling: Adjust glyph proportions with configurable scaling
• Custom Vertical Metrics: Set custom ascender/descender or scale existing line height
• Enable/Disable Overrides: Toggle individual override fonts via configuration
• Variable Font Support: Instantiate variable fonts with custom axis values

All fonts for a given style are merged in a single FontForge process, using the first font as the base.