merge: Merge multiple fonts into one

fontTools.merge provides both a library and a command line interface (fonttools merge) for merging multiple fonts together.

class fontTools.merge.Merger(options=None)[source]

Font merger.

This class merges multiple files into a single OpenType font, taking into account complexities such as OpenType layout (GSUB/GPOS) tables and cross-font metrics (e.g. hhea.ascent is set to the maximum value across all the fonts).

If multiple glyphs map to the same Unicode value, and the glyphs are considered sufficiently different (that is, they differ in any of paths, widths, or height), then subsequent glyphs are renamed and a lookup in the locl feature will be created to disambiguate them. For example, if the arguments are an Arabic font and a Latin font and both contain a set of parentheses, the Latin glyphs will be renamed to parenleft#1 and parenright#1, and a lookup will be inserted into the to locl feature (creating it if necessary) under the latn script to substitute parenleft with parenleft#1 etc.


  • All fonts must currently have TrueType outlines (glyf table).

    Merging fonts with CFF outlines is not supported.

  • All fonts must have the same units per em.

  • If duplicate glyph disambiguation takes place as described above then the

    fonts must have a GSUB table.


Currently unused.


Merges fonts together.


fontfiles – A list of file names to be merged


A fontTools.ttLib.TTFont object. Call the save method on this to write it out to an OTF file.