cellwidths-gen / CLI tool for generating Vim's setcellwidths configuration

cellwidths-gen is a CLI tool that generates a Vim script to configure character widths for a given TrueType font file (.ttf). This script helps Vim correctly distinguish between half-width and full-width characters, which is essential for proper alignment and display of text, especially in CJK environments.

Features

• Parses TrueType font files to extract character width information.
• Generates a Vim script that defines character width rules using the setcellwidths() function.
• Automatically detects the font name and creates a self-contained Vim script that applies the settings only when the specified font is in use.

Usage

cellwidths-gen <path-to-font-file> [options]

Arguments

• <path-to-font-file>: The path to the TrueType font file (.ttf) you want to process.

Options

• -o, --output <path>: The path to the output Vim script file. (Default: ./cellwidths.vim)
• -h, --help: Show help.

Example

cellwidths-gen /path/to/your/font.ttf -o ~/.vim/plugin/cellwidths_myfont.vim

Or, if you're using Neovim:

cellwidths-gen /path/to/your/font.ttf -o ~/.config/nvim/plugin/cellwidths_myfont.vim

This command will generate a cellwidths.vim file in your Vim's plugin directory. When you start Vim, this script will automatically be loaded. It will check if the guifont option is set to the font you specified, and if so, it will apply the correct character width settings.

How it works

The tool reads the hmtx (Horizontal Metrics) and cmap (Character to Glyph Mapping) tables from the TrueType font file. It determines the advance width of each character and groups them into two categories: half-width and full-width. Based on this information, it generates a Vim script that uses the setcellwidths() function to tell Vim how to treat each character.

The generated script is designed to be "smart" - it only applies the settings when the guifont option matches the font name extracted from the font file. This means you can have multiple cellwidths.vim files for different fonts, and the correct one will be used automatically.

License

This project is licensed under the MIT License. See the LICENSE file for details.