`cmap` table

Maps character codes (Unicode codepoints) to glyph indices.

Scope

Format family: Shared SFNT
Table tag in JSON: cmap

Specs

https://learn.microsoft.com/en-us/typography/opentype/spec/cmap
OpenType table registry: https://learn.microsoft.com/en-us/typography/opentype/spec/otff#font-tables

JSON Skeleton

This skeleton reflects fields currently parsed/written by Font Flux JS for this table.

json

{
  "tables": {
    "cmap": {
      "version": 0,
      "encodingRecords": null,
      "subtables": null,
      "_checksum": 0
    }
  }
}

Top-level Fields

version - number (0..65535) [spec type: uint16] (must be 0)
encodingRecords - implementation-defined
subtables - implementation-defined

Additional Nested Keys Seen In Implementation

platformID
encodingID
subtableIndex
firstCode
entryCount
idDelta
idRangeOffset
endCode
startCode
startCharCode
endCharCode
startGlyphID
glyphID
startUnicodeValue
additionalCount
unicodeValue
defaultUVSBytes
nonDefaultUVSBytes

Notes

Preserve _checksum for stable round-tripping.
If a table is only partially understood, prefer keeping unknown bytes in _raw instead of dropping data.
Validate with .validate() after edits.