Font subsetting is the process of reducing a font file’s size by including only the specific characters or glyphs needed. This was previously handled through static font asset. However, since font files are now required by the Advanced Text Generator, static font assets are no longer supported.
To subset fonts, use external tools, such as the command-line FontTools library.
pip install fonttools.pyftsubset is a command-line tool included in the FontTools library, used for font subsetting. It allows you to create a smaller font file by including only the specific characters or glyphs you need, which helps reduce file size and improve performance.
Assume you have an example font file named example.ttf. The following examples show how to use pyftsubset to subset the font file by Unicode ranges, text, or glyphs.
To subset for Basic Latin and Latin–1 Supplement, use the following command:
pyftsubset example.ttf --unicodes=U+0000-007F,U+00A0-00FF --output-file=subsetted.ttf
To subset font files by text, use the following command:
pyftsubset example.ttf --text="Hello, World! test" --output-file=subsetted.ttf
To subset by glyph names, use the following command:
pyftsubset example.ttf --glyphs=A,B,C --output-file=subsetted.ttf
By default, subsetting might remove some OpenType layout features, such as kerning or ligatures. You can use the --layout-features option to specify the features you want to keep. For example --layout-features='kern,liga'. To retain all features, use: --layout-features=*