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}

• PostScript hinting
• Autohinting TrueType fonts with ttfautohint