Fontmake-STAT-patches.md

Fontmake STAT Patch Process

This is the process as of 8/8/18 since the current fix-vf-meta.py script does not work on fonts with more than one axis.

Process

0. Change STAT minor version number to 1. In name table, check that all entries and variations of the font name are “Font Italic” or “Font Regular”, and not some odd combo like “Font Regular Italic”
1. OPTIONAL (Fonts are fine without this step) Copy Windows name records 1–14 to Mac name records, change all IDs after nameID to: platformID="1" platEncID="0" langID="0x0" unicode="True"
2. If the family has italic styles, add a name table entry “Italic” if there is not already one present
3. If the family has a width axis, add the name table entries to address the different widths of instances. Entries should address only one axis
   1. Example: “Condensed” and “Normal”
   2. For a script, perhaps this could look to the values of instances on the fvar table and generate a canonical width string accordingly
4. Repeat step three for as many additional axes the family has
5. In the STAT table, add an <Axis> for Italic (using the same nameID in step3) to the <DesignAxisRecord> (be sure to update Axis index and AxisOrdering value). Also remove the italic axis from fvar table if it is present, and remove all coordinate values for that axis.
   1. The Italic axis does not need to be added to the fvar table in families that have separate roman and italic forms. The OT spec acknowledges the axis count of the STAT table relative to the fvar table: “In a font with an 'fvar' table, this value must be greater than or equal to the axisCount value in the 'fvar' table”
   2. Be Careful when removing an axis from the fvar table, you must also remove the respective VarRegionAxis in the HVAR, MVAR, GDEF, VVAR, and BASE tables
   3. It appears the fonts operate properly on Windows even if the axes do not match up in the fvar tables between fonts (i.e. if romans have a widths axis and italics do not)
6. Add <AxisValueArray> table to STAT table and add AxisValue’s for all weights these can be format1 or format2
   1. This can be pulled from the fvar table, using both the subfamilyNameID as the ValueNameID value and the “wght” value as the Value value
7. Add AxisValue’s to the STAT table for the additional axes. Width for example would have an entry for Condensed and one for Normal. Can be either format1 or format2 3. Remember to set the appropriate flags for these entries to mark some as default, otherwise the names of instances on Windows will be messed up.
8. For the roman VF add AxisValue Format="3" with the string Regular on the Italic axis. The value will be 0.0 and the linkedValue will be 1.0. This should link the Regular VF to the Italic VF
   1. For the nameID I like to use the Regular from nameId 2 since that one is for the family rather than referring to a single style, even though it really makes no difference, a string is a string :)
   2. Remember to set <Flags value="2"/> if this is the roman font
9. For the italic VF ad an Axis value Format=1 to the STAT table, set it to 1.0 and have the flag set to 0 since the italic style is not the default and should be visible in the name of the font

Example ttx from Cabin Roman VF

  <STAT>
    <Version value="0x00010001"/>
    <DesignAxisRecordSize value="8"/>
    <!-- DesignAxisCount=3 -->
    <DesignAxisRecord>
      <Axis index="0">
        <AxisTag value="wght"/>
        <AxisNameID value="256"/>  <!-- Weight -->
        <AxisOrdering value="0"/>
      </Axis>
      <Axis index="1">
        <AxisTag value="wdth"/>
        <AxisNameID value="257"/>  <!-- Width -->
        <AxisOrdering value="1"/>
      </Axis>
      <Axis index="2">
        <AxisTag value="wdth"/>
        <AxisNameID value="266"/>  <!-- Italic -->
        <AxisOrdering value="2"/>
      </Axis>
    </DesignAxisRecord>
    <!-- AxisValueCount=7 -->
    <AxisValueArray>
      <AxisValue index="0" Format="1">
        <AxisIndex value="0"/>
        <Flags value="0"/>
        <ValueNameID value="258"/>  <!-- Regular -->
        <Value value="400.0"/>
      </AxisValue>
      <AxisValue index="1" Format="1">
        <AxisIndex value="0"/>
        <Flags value="0"/>
        <ValueNameID value="259"/>  <!-- Medium -->
        <Value value="500.0"/>
      </AxisValue>
      <AxisValue index="2" Format="1">
        <AxisIndex value="0"/>
        <Flags value="0"/>
        <ValueNameID value="260"/>  <!-- SemiBold -->
        <Value value="600.0"/>
      </AxisValue>
      <AxisValue index="3" Format="1">
        <AxisIndex value="0"/>
        <Flags value="0"/>
        <ValueNameID value="261"/>  <!-- Bold -->
        <Value value="700.0"/>
      </AxisValue>
      <AxisValue index="4" Format="3">
        <AxisIndex value="2"/>
        <Flags value="2"/>
        <ValueNameID value="2"/>  <!-- Regular -->
        <Value value="0.0"/>
        <LinkedValue value="1.0"/>
      </AxisValue>
      <AxisValue index="5" Format="1">
        <AxisIndex value="1"/>
        <Flags value="0"/>
        <ValueNameID value="267"/>  <!-- Condensed -->
        <Value value="50.0"/>
      </AxisValue>
      <AxisValue index="6" Format="1">
        <AxisIndex value="1"/>
        <Flags value="2"/>
        <ValueNameID value="268"/>  <!-- Normal -->
        <Value value="100.0"/>
      </AxisValue>
    </AxisValueArray>
    <ElidedFallbackNameID value="2"/>  <!-- Regular -->
  </STAT>