splitfont

splitfont [OPTIONS] input_font_file [output_prefix_or_directory]

input_font_file
    The path to the source font file that needs to be processed and split.

output_prefix_or_directory
    An optional argument specifying either a prefix for the names of the output files or a directory where the split font files should be placed. If omitted, a default might be used or files created in the current directory.

-c <character_range>
    Defines specific character ranges (e.g., Unicode code points like U+0000-U+00FF) to use as criteria for splitting the font, creating separate files for each specified range.

-o <output_directory>
    Specifies the target directory where the resulting split font files will be saved.

-p <output_prefix>
    Sets a common prefix for the filenames of the multiple output font files generated by the splitting process.

-v
    Enables verbose mode, providing more detailed information about the splitting process, such as progress updates or file generation details.

-h
    Displays a help message, typically showing usage information and a list of available options.

The splitfont utility is typically employed to divide a large font file into multiple smaller font files. This is often done for bitmap fonts, such as those in the Bitmap Distribution Format (BDF), commonly used within the X Window System. The primary purpose of splitting fonts can be to optimize font loading, manage memory more efficiently, or to create subsets of a font containing specific character ranges or languages.

While not a standard command with a dedicated man page on most modern Linux distributions, its functionality is sometimes incorporated into larger font processing toolchains or custom scripts. It helps in breaking down monolithic font files into more manageable components, especially useful in environments with resource constraints or for specific font distribution needs.

The splitfont command is not a standard utility found in most Linux distributions' core packages. Its existence and functionality are highly dependent on specific font tool suites (e.g., older X11 font utilities, FontForge scripts, or custom scripts). Users should not expect it to be available by default and may need to compile it from source or locate it within specialized font development environments. The exact syntax and available options can vary significantly depending on the specific implementation found.

Optimizing X11 Font Loading: Breaking down large BDF or PCF fonts into smaller, character-set-specific files to reduce memory footprint and speed up font loading for particular locales.
Creating Font Subsets: Generating smaller font files containing only the glyphs required for a specific language or application, thereby significantly reducing overall file size for distribution or embedding.

The concept of splitting fonts, particularly bitmap fonts like BDF, emerged in the context of X Window System font management. Large font files, especially those containing many character sets, could be inefficient to load or manage on systems with limited resources. Tools or scripts designed to 'split' these fonts into smaller, more manageable parts for specific character ranges or languages became useful. While no single, universally adopted splitfont command exists, the functionality it implies has been implemented in various forms within font processing toolchains and custom utilities, primarily aimed at optimizing X11 font distribution and rendering.

bdftopcf(1), mkfontdir(1), fontforge(1), otfinfo(1), ttx(1)