RoboFont offers a direct way to inject TrueType hinting instructions in a binary font while generating a TrueType font. The lib keys were initiated by Petr van Blokland for the RoboHint tools he was developing. Black Foundry developped TTH on top of these lib keys.

From early 2021 the UFO specification has a similar way to support TrueType hinting data, RoboFont does not yet support this yet. Read more of the public lib keys for font.lib and public lib keys for glyph.lib

Glyph Lib keys

glyf table

com.robofont.robohint.assembly
list of assembly code

Font Lib keys

maxp

com.robofont.robohint.maxp
base name
com.robofont.robohint.maxp.maxZones
int
com.robofont.robohint.maxp.maxTwilightPoints
int
com.robofont.robohint.maxp.maxStorage
int
com.robofont.robohint.maxp.maxFunctionDefs
int
com.robofont.robohint.maxp.maxInstructionDefs
int
com.robofont.robohint.maxp.maxStackElements
int
com.robofont.robohint.maxp.maxSizeOfInstructions
int
com.robofont.robohint.maxp.maxComponentElements
int

cvt

com.robofont.robohint.cvt
list
needs to be a continuous list of values with 0 at the missing slots.
notice the extra space at the end of the lib key: "com.robofont.robohint.cvt "

fpgm

com.robofont.robohint.fpgm
list of assembly code

prep

com.robofont.robohint.prep
list of assembly code

gasp

com.robofont.robohint.gasp
dict of int ranges fe {8: 2, 16: 1, 65535: 3}

hdmx

com.robofont.robohint.hdmx
dict
{ppem : {glyphname: width}}

VDMX

com.robofont.robohint.VDMX
dict
{
  version : 1, # recommended
  ratRanges : [
                  {bCharSet : int, xRatio : int, yStartRatio : int, yEndRatio: int, groupIndex : int}
              ],
  groups : [
          {yPel : yMax, yMin}
          ]
}

LTSH

com.robofont.robohint.LTSH
dict
{glyphname : yPel}
Last edited on 15/07/2021