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vhea table ​

Provides vertical layout metrics — ascender, descender, and line gap for vertical text.

Scope ​

  • Format family: Shared SFNT
  • Table tag in JSON: vhea

Specs ​

JSON Skeleton ​

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

json
{
  "tables": {
    "vhea": {
      "version": 0,
      "vertTypoAscender": 0,
      "vertTypoDescender": 0,
      "vertTypoLineGap": 0,
      "advanceHeightMax": 0,
      "minTopSideBearing": 0,
      "minBottomSideBearing": 0,
      "yMaxExtent": 0,
      "caretSlopeRise": 0,
      "caretSlopeRun": 0,
      "caretOffset": 0,
      "reserved1": 0,
      "reserved2": 0,
      "reserved3": 0,
      "reserved4": 0,
      "metricDataFormat": 0,
      "numOfLongVerMetrics": 0,
      "_checksum": 0
    }
  }
}

Top-level Fields ​

  • version - number [spec type: Version16Dot16] (0x00010000 (1.0) or 0x00011000 (1.1))
  • vertTypoAscender - number [spec type: FWORD] ((v1.0: "ascent"))
  • vertTypoDescender - number [spec type: FWORD] ((v1.0: "descent"))
  • vertTypoLineGap - number [spec type: FWORD] ((v1.0: "lineGap"))
  • advanceHeightMax - number [spec type: UFWORD]
  • minTopSideBearing - number [spec type: FWORD]
  • minBottomSideBearing - number [spec type: FWORD]
  • yMaxExtent - number [spec type: FWORD]
  • caretSlopeRise - number (-32768..32767) [spec type: int16]
  • caretSlopeRun - number (-32768..32767) [spec type: int16]
  • caretOffset - number (-32768..32767) [spec type: int16]
  • reserved1 - number (-32768..32767)
  • reserved2 - number (-32768..32767)
  • reserved3 - number (-32768..32767)
  • reserved4 - number (-32768..32767)
  • metricDataFormat - number (-32768..32767) [spec type: int16] (0 for current format)
  • numOfLongVerMetrics - number (0..65535) [spec type: uint16]

Additional Nested Keys Seen In Implementation ​

  • version
  • vertTypoAscender
  • vertTypoDescender
  • vertTypoLineGap
  • advanceHeightMax
  • minTopSideBearing
  • minBottomSideBearing
  • yMaxExtent
  • caretSlopeRise
  • caretSlopeRun
  • caretOffset
  • reserved1
  • reserved2
  • reserved3
  • reserved4
  • metricDataFormat
  • numOfLongVerMetrics

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.