Here follows a list of custom font lib keys supported by RoboFont. If you are looking the TrueType hinting keys check the TrueType hinting

Glyph Lib Keys

public.markColor

This key is used for representing the mark color.

See also public.markColor on the UFO website

Font Lib Keys

com.typemytype.robofont.italicSlantOffset

number, default is 0

See also setting the italic slant offset

public.glyphOrder

This key is used for representing the user’s preferred glyph order in the font. The glyph order is stored as a list of glyphs names. Glyph names must not occur more than once. Glyph names in the font may not appear in the order. The order may contain glyphs that are not in the font.

See also Public Glyphorder on the Unified Font Object website

com.defcon.sortDescriptor

list, default is empty

Sort descriptions used for representing glyph order in the font editor.

Fallback for public.glyphOrder

See also sortGlyphNames on defcon.robotools.dev

The ‘roundTolerance’ argument controls the rounding of point coordinates.

It is defined as the maximum absolute difference between the original

float and the rounded integer value.

The default tolerance of 0.5 means that all floats are rounded to integer;

a value of 0 disables rounding; values in between will only round floats

which are close to their integral part within the tolerated range.

check https://fonttools.readthedocs.io/en/latest/pens/t2CharStringPen.html

font.lib[“com.typemytype.robofont.roundTolerance”] = 0.5

boolean, default is True

font.lib[“com.typemytype.robofont.shouldAddPointsInSplineConversion”] = True

com.robofont.generateFeaturesWithFontTools

boolean, default is False

com.robofont.generateCheckComponentMatrix

boolean, default is True

If this lib key is set to True, components with a transformation impling more than translation will be decomposed, otherwise they will stay as components.

Only applies when the global generate decompose is set to False.

com.robofont.generateTurnOnSubroutinizations

boolean, default is False

Adds subroutinization in FDK makeotf.

com.robofont.generateOmitNotMentionedGlyphs

boolean, default is False

See also -gs flag on MakeOTF OpenType/CFF compiler - User Guide

com.robofont.fontCompilerTool

string, either "fontmake" or "afdko", default is "afdko"

Which compiler is used for generating binaries.

com.typemytype.robofont.compileSettings.autohint

boolean, default is True

com.typemytype.robofont.compileSettings.checkOutlines

boolean, default is True

Performs a remove overlap when set to True.

com.typemytype.robofont.compileSettings.createDummyDSIG

boolean, default is True

It creates a dummy digital signature open type table necessary for using the font in Microsoft Office applications

See also Digital Signature Table on the Microsoft docs and Making OT/TTF layout features work in MS Word 2010

com.typemytype.robofont.compileSettings.decompose

boolean, default is False

Decompose components during export.

com.typemytype.robofont.compileSettings.generateFormat

string, either "ttf" or "otf" or "pfa"

The format use to generate binaries.

com.typemytype.robofont.compileSettings.layerName

string, if non existing the default layer will be used

The layer to be used for export.

com.typemytype.robofont.compileSettings.path

string, path where the last binary has been stored

Overriden every time a binary is generated.

com.typemytype.robofont.compileSettings.releaseMode

boolean, default is False

See also -f flag on MakeOTF Options on Adobe Type Tools

com.typemytype.robofont.roundTolerance

float and the rounded integer value.

The roundTolerance argument controls the rounding of point coordinates. It is defined as the maximum absolute difference between the original The default tolerance of 0.5 means that all floats are rounded to integer; a value of 0 disables rounding; values in between will only round floats which are close to their integral part within the tolerated range.

See also t2CharStringPen on the fonttools website

com.typemytype.robofont.shouldAddPointsInSplineConversion

boolean, default is True

When set to True points will be added during conversion from bezier to TrueType splines to preserve the curve. When Set to False not points will be added and the amounts of points will be preserved.

com.typemytype.robofont.smartSets

list of dictionaries (default is empty), with the following keys:

• uniqueKey: unique key to identify the smart set item, must be unique, string.
• smartSetName: name of the smart set item, string.
• query: a predicate string, there is no query when glyphNames are set, see also Predicate Format String Syntax.
• glyphNames: a list of glyph names (strings) no need to set a query (build automatically when glyphNames are set).
• group: a list of smart sets items.

com.typemytype.robofont.splineConversionFuzz

number, default is 2

Amount of distance in UPM between 1/4 of the curve and 3/4 of the curve that is accepted before adding an extra point.

com.typesupply.feaPyFoFum.compileFeatures

boolean, default is False

If True features will be compiled with feaPyFoFum.

com.typesupply.ufo2fdk.glyphOrderAndAliasDB

string, default is empty

When a font has the public.postscriptNames lib this will not be used. Otherwise, RoboFont will look for this one and it will send it to FDK.

See also MakeOTF OpenType/CFF compiler User Guide

public.postscriptNames

dictionary, glyphs names as keys and Postscript glyph names as values

This defines a preferred glyph name to Postscript glyph name mapping for glyphs in the font.

Both keys and values must be strings. The values must conform to the Postscript glyph naming specification.

The dictionary may contain glyph names that are not in the font. The dictionary may not contain a key, value pair for all glyphs in the font. If a glyph’s name is not defined in this mapping, the glyph’s name should be used as the Postscript name.

See also public.postscriptNames on the UFO website

public.skipExportGlyphs

This key is a list of glyph names used for representing glyphs that the user does not want exported to the final font file.

See also public.skipExportGlyphs on the UFO website

public.truetype.instructions

This key provides a dict defining a set of TrueType instructions assembly code for a glyph.

See also public TrueType instructions