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OpenType specification change log (OpenType 1.4)

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Version 1.0 - released April, 1997

Version 1.01 - released October, 1997

Summary of Changes:

  • mmfx.htm, fvar.htm, mmsd.htm, otover.htm, recom.htm - edits throughout
  • loca.htm - changed long-aligned to word-aligned for local offsets
  • wgl4.htm - added reference to Euro symbol
  • dsig.htm - added note about system use of dsig table to distinguish OT from TT fonts
  • ttoreg.htm - added VIT, TRK, and ROM lang sys tags
  • otff.htm - rearranged table list
  • base.htm - change to basecoordformat3 data type
  • gpos.htm - pairposformat1 subtable valuerecord becomes offset
  • kern.htm - gpos clarification
  • name.htm - added name id’s 13 and 14
  • ltsh.htm - clarified option for fixed-pitch fonts
  • vdmx.htm - version 1 added to vdmx table
  • os2.htm - added codepage range 8 for Vietnamese; added new vendor id’s, including UNKN

Version 1.1 - released April, 1998

Summary of Changes:

  • CFF and Type2 specs updated
  • chapter2.htm - corrected typo in figure 2d (fig2d.gif)
  • dsig.htm - added info about location of DSIG table; added list of sfnt structural requirements
  • feattags.htm - created more comprehensive list and description of layout feature tags
  • gpos.htm - corrected illustration 4f (fig4f.gif)
  • head.htm - added bit 12 (converted) to flags field
  • hhea.htm - removed CFF restriction listed in numberOfHMetrics field; added caretOffset field.
  • maxp.htm - added version 0.5 table (numGlyphs field); general editing
  • name.htm - added name id’s 16, 17, and 18; corrected name id example
  • os2.htm - added new version (2), adding new fields sxHeight, sCapHeight, usDefaultChar, usBreakChar, usMaxLookup; clarified sTypoAscender and sTypoDescender fields; changed some Unicode range values to reflect Unicode 2; updated registered vendors
  • otff.htm - general editing; added description of two types of TTC headers, and DSIG table location
  • recom.htm - general editing

Version 1.2 - released November, 1998

Summary of Changes:

  • Data type notation and spelling corrected throughout
  • base.htm - added BaseCoord Table Format 4
  • chapter2.htm - corrected example 3; refined description of next glyph; reserved RightToLeft lookup flag; corrected descriptions of LookupFlag bits
  • cmap.htm - removed legacy encodings
  • dsig.htm - updated field names and format of signature record; added step to creation of content digest
  • feattags.htm - registered new features crcy, dnom, jajp, kokr, lfbd, numr, rtbd, vivn, vrt2, zhcn, zhtw; removed features trak, vrot; edited and clarified descriptions of features afrc, altv, c2sc, calt, case, cpsp, dlig, dpng, expt, fina, frac, fwid, halt, hlig, lngl, hwid, init, ital, jp78, jp90, kern, lnum, medi, mgrk, onum, opbd, ordn, ornm, palt, pnum, pwid, qwid, smcp, smpl, sups, tnam, tnum, trad, twid, vert
  • gdef.htm - added MarkAttachClassDef to header, and MarkAttachmentType bit setting to LookupFlag bits; added CaretValue Table Format 4
  • glyf.htm - added table detailing component record structure
  • gsub.htm - added format 6, for chaining contextual substitution; general editing
  • gpos.htm - added format 8, for chaining contextual positioning; clarified pair positioning operations; corrected Example 10; clarified coordinate system description; refined description of when a lookup is finished; added AnchorTable Format 4; general editing
  • head.htm - added note about fontRevision field; clarified description of compression flag
  • hhea.htm - corrected description of numberOfHMetrics
  • mmfx.htm - corrections throughout; added MMFXIdZero
  • name.htm - general editing
  • os2.htm - renamed usMaxLookup to usMaxContext; edited descriptions of defaultChar and breakChar; updated registered vendors
  • otff.htm - general editing; added ulDsigTag and related fields to TTC header; added datatypes LONGDATETIME; clarified checksum calculations; added tag name restrictions; clarified use of version numbers
  • post.htm - renamed FormatType to Version
  • vhea.htm - replaced mention of centerline with vertical baseline; corrected description of numOfLongVerMetrics
  • CFF.pdf and Type2.pdf updated (December 1998)
  • Several PostScript glyph names corrected in the WGL tables (18 December 1998)
  • name.htm - Descriptions of name ID 13 and 14 corrected (29 January 1999)
  • mmsd.htm - Attribute flags corrected (29 January 1999)
  • head.htm - Data type of xMin corrected (29 January 1999)

Version 1.25 - released July, 2000

Summary of Changes:

  • feattags.htm (now featurelist.htm) (Feature Tags) -
    • Features added:
      abvm (Above-base Mark Positioning); abvs (Above-base Substitutions); akhn (Akhand); blwf (Below-base Forms); blws (Below-base Substitutions); clig (Contextual Ligatures); cswh (Contextual Swash); curs (Cursive Positioning); dist (Distances); falt (Final Glyph on Line Alternates); half (Half Forms); haln (Halant Forms); hkna (Horizontal Kana Alternates); isol (Isolated Forms); jalt (Justification Alternates); locl (Localized Forms) (replaces jajp, kokr, vivn, zhch, and zhtw); mkmk (Mark to Mark Positioning); nukt (Nukta Forms); pres (Pre-base substitutions); pstf (Post-base Forms); psts (Post-base Substitutions); rphf (Reph Forms); ruby (Ruby Notation Forms); size (Optical Size); vatu (Vattu Variants); vhal (Alternate Vertical Half Metrics); vkna (Vertical Kana Alternates); vkrn (Vertical Kerning) vpal (Proportional Alternate Vertical Metrics).
    • Features removed:
      crcy (Currency), dpng (Diphthongs), jajp (Japanese Forms), kokr (Korean Forms), vivn (Vietnamese Forms), zhcn (Simplified Chinese Forms), zhtw (Traditional Chinese Forms).
    • Features modified:
      aalt: Added ordering suggestion, reworked user interface suggestions, clarified implementation recommendation, feature interaction and function.
      altv: changed tag to valt.
      c2sc, dlig: Clarified function, example and feature interaction.
      calt, case, dnom, expt, halt, hist, hwid, jp78, jp83, jp90, kern, lfbd, liga, lnum, numr, onum, pwid, qwid, rtbd, smpl, sups, titl, twid, valt: Clarified feature interaction.
      fina, init, medi, rand, salt, swsh: Clarified user interface suggestion and feature interaction.
      frac: Added numr and dnom extensions, clarified feature interaction.
      fwid, palt: Clarified feature interaction and function.
      hngl: Clarified feature interaction and implementation recommendation.
      ital: Clarified function and feature interaction.
      mark: Added example, application interface, user interface suggestion, script sensitivity, feature interaction. Modified recommended implementation.
      mset: Added example.
      nalt: Clarified user interface suggestion, implementation recommendation and feature interaction.
      opbd: Added lfbd and rtbd extensions; clarified user interface suggestion and feature interaction.
      ordn: Clarified script sensitivity, corrected lookup type, clarified implementation recommendation and feature interaction.
      ornm: Clarified user interface suggestion, implementation recommendation, feature interaction and function description.
      smcp: Added note about dotlessi; clarified function and feature interaction.
      trad: corrected terminology (hanzi, not hanja), clarified user interface suggestion and implementation recommendation.
      vert: Clarified feature interaction and added ordering recommendation; extended application interface notes.
      vrt2: Changed ‘friendly’ name, clarified feature interaction and added ordering recommendation; added ATM/OTF driver information and descriptions of how to construct the rotated glyphs in the Function section. zero: Clarified user interface suggestion.
    • Features relocated:
      mark and mset have been moved from the Metric Behaviors category, to the Other Substitutions category for consistency in classification.
  • chapter2.htm - modified description of FeatureParams field for a non-null offset (the size feature uses it).

Version 1.3 - released April, 2001

Summary of Changes:

  • Multiple Master support in OpenType, discontinued. The following tables pertaining to it have been removed from this version of the OpenType specification: 'fvar', 'MMSD', 'MMFX'.
  • base.htm
    • BaseTagList Table
      Added a sentence with a link to the baseline tags in the tags registry.
    • BaseCoord Format 4
      Removed.
  • cff.htm
    • Removed references to MM fonts in the CFF and Type 2 Charstring Format specifications. See the change log in each specification for additional changes made.
  • chapter2.htm
    • Table Organisation
      In paragraph 3, changed the number of types of GSUB and GPOS lookups. Phrase added to Paragraph 4 to exclude the Extension lookup.
    • LookupFlag bit enumeration
      Name of the first bit reverted back to RightToLeft. Provided newer description of its use.
    • Coverage Table
      Phrase added to exclude the Extension lookup.
  • cmap.htm
    • Merged paragraph 3 and 4 in the introduction section.
    • Added notes that fonts for Windows that support UCS-4 characters (surrogates), need to use an encoding ID 10 and format 12.
    • The version field has been renamed as ‘language’, to align it with Apple’s TT spec. Added a note to clarify the use of this field.
    • Added information that platform ID 3, encoding ID 7,8 and 9 are reserved.
    • Added platform ID 3, encoding ID 10.
    • Swapped the description of encoding ID 3 and 4. They were incorrectly mapped to Big5 and PRC respectively, in earlier versions of the specification.
    • Added a note on OTF Windows compatibility mapping.
    • Formats 2, 4, 6.
      Made the description of the ‘length’ field in these formats consistent with the rest of the formats.
    • Format 2
      Removed the duplicate entry for subHeaders[ ].
    • Format 4
      Corrected ‘endCode’ and ‘startCode’ values in the example for this format.
    • Supporting 4-byte character codes (Formats 8, 10, 12)
      Added these new formats.
  • ebdt.htm
    • Minor typo in the name of ebdtComponent corrected.
  • feattags.htm (now featurelist.htm)
    • Added features 'ccmp', 'fin2', 'fin3', med2' and 'rlig'.
    • Clarified the Feature Interaction sections for 'kern', 'vkrn'.
    • Updated GSUB lookup type to be used, in the Recommended implementation section of 'ordn'.
  • fvar.htm
    • This table removed.
  • gdef.htm
    • Introduction
      Added information on the MarkAttachClassDef field.
    • Overview
      Updated image to contain MarkAttachClassDef.
    • GDEF Header
      Added missing information on the MarkAttachClassDef field.
    • GDEF Header Table
      Added the note that offsets might be null for the GlyphClassDef, AttachList, LigCaretList, MarkAttachClassDef
    • GlyphClassDef Enumeration List
      An explanatory note added for definition of ligatures and component glyphs.
    • Mark Attachment Class Definition Table
      An explanatory section and example 7 added.
    • CaretValue: Format 4
      This format used by MM fonts removed.
  • gpos.htm
    • Corrected the link “Common Table Formats” to read “OpenType Common Table Formats”; throughout table.
    • Table Organization
      Updated the image. Added links for all lookup types. Added Extension positioning as LookupType 9, types 10+ are now Reserved.
    • PairPosFormat1 subtable
      PairSet field corrected to specify it as an array of Offsets.
    • Lookup Type 6
      Sentence added to clarify input context for MarkToBase, MarkToLigature and MarkToMark positioning tables.
    • LookupType 9: Extension Positioning
      This new lookup type added.
    • ValueRecord table
      Removed XIdPlacement, YIdPlacement, XIdAdvance, YIdAdvance and the sentence following the table.
    • ValueFormat bit enumeration
      Removed XIdPlacement, YIdPlacement, XIdAdvance, YIdAdvance and the sentence following the table.
    • Anchor Table: Format 4
      Removed.
  • gsub.htm
    • Corrected the link “Common Table Formats” to read “OpenType Common Table Formats”; throughout table.
    • Substituting Glyphs with OpenTypeTM
      Types of lookups corrected to six. Added an explanation to the ligature substitution section, to clarify the location occupied by a ligature glyph when it replaces a sequence of glyphs. Missing paragraph on Chaining contextual substitution added.
    • Table Organization
      Updated image.
    • LookupType Enumeration table for glyph substitution
      Added links for all lookup types. Added Extension Substitution as the 7th lookup type. This hence classifies types 8+ as Reserved.
    • LookupType 2:
      Prohibited the deletion of an input glyph, and added that GlyphCount should always be greater than 0.
    • Chaining Context Substitution Format 1: Simple Chaining Context Glyph Substitution
      Added that the match for the string ‘backtrack sequence + input sequence + lookahead sequence’ takes place in the simplest of cases; and that lookup flag values affect backtrack/lookahead sequences. Since the input sequence includes the covered glyph, removed “covered glyph” from the above string.
    • LookupType 7: Extension Substitution
      This new lookup type added.
  • head.htm
    • table
      Clarified description for bit 1, 5-10.
      Added specification for bit 13.
  • hhea.htm
    • table
      Added a footnote for the fields Ascender, Descender and LineGap.
  • hmtx.htm
    • Added a note that the advanceWidth for each glyph in CFF OpenType fonts must match its x width in the CFF table.
  • loca.htm
    • Corrected minor typo.
  • maxp.htm
    • Added a note to indicate the difference in representing the fractional part of a version number when it is non-zero.
  • mmfx.htm
    • This table removed.
  • mmsd.htm
    • This table removed.
  • name.htm
    • Minor rewording of text done in the introduction section related to fonts for the Macintosh.
    • Platform ID, specific encoding ID and languageId information combined into one table.
    • Unicode platform-specific encoding IDs (platform ID = 0)
      This new table added.
    • Microsoft platform-specific encoding IDs
      This table replaced with a more comprehensive table from the cmap.htm.
    • Mac platform-specific encoding IDs:
      Clarified IDs 2 and 25. Corrected typo in ID 32.
    • Mac language IDs:
      Newer IDs added 23-150.
    • ISO specific encodings (platform ID=2)
      Marked as deprecated. Minor typo in the sentence below the table corrected.
    • Custom platform-specific encoding IDs (platform ID = 4)
      Newer platform ID added.
    • Name IDs
      Added newer description for nameID 5. Added nameID 19 and 20.
    • Examples
      Added example for nameID 19.
    • LCID-CP list
      Updated this list.
  • os2.htm
    • xAvgCharWidth.description
      Comments for this field updated.
    • fsType.table
      Added Bit Mask and description details for the case when no bit is set; added Bit Mask value 0x0001.
    • fsType.comments
      Information on setting Bit Masks consolidated into the description column of the table. Removed the redundant section below the table.
    • yStrikeoutPosition.description
      Added that this is the distance of the top of the strikeout stroke.
    • panose.description
      Removed dead url for the PANOSE evaluation document, added that the “greybook” reference could be used instead.
    • ulUnicodeRange.table
      Updated the Unicode standard version number to 3.0 in the description for these fields. Added bits 70- 127. Added a footnote for setting bit 57 (Surrogates).
    • usFirstCharIndex.description
      Minor correction-- added the word platform specific.
    • sTypoAscender and sTypodescender
      Minor corrections done; “design space” now referred to as “ideo em box” in the descriptions; added a links to recom.htm for these fields.
    • usWinAscent
      Explanatory note added to explain the circumstances in which clipping will take place.
    • usWinDescent
      Explanatory note added to explain the circumstances in which clipping will take place.
    • sxHeight
      Added a note that this metric can be used in font substitution.
    • usDefaultChar
      Added that for a given font, missing glyphs will be displayed using the content of glyph 0 in the selected font.
  • otff.htm
    • Version Numbers
      Added explanation that representation of a non-zero fractional part in version numbers, differs from the representation of the matissa.
    • Tables Related to PostScript Outlines
      Removed links and description details for the fvar, MMSD and MMFX tables.
    • Advanced Typographic Tables
      Added a link to OpenType Layout Common Table Formats.
    • Other OpenType Tables
      Added the VORG table name to the list.
  • otover.htm
    • Related documentation
      Removed sections in the description related to MM fonts.
  • post.htm
    • table.version.description
      Added versions 2.5 and 3.0
    • table.underlinePosition.description
      PostScript information added.
    • version2.0
      Updated name and description details in the table contents
    • version2.5
      Updated table contents, added that this version has been deprecated.
  • recom.htm
    • 'BASE' Table
      This section added.
    • 'cmap' table
      Added details on requirements that need to be satisfied by surrogate fonts on Windows.
    • 'head' Table
      Added details regarding usage of the fontRevision value.
    • 'hhea' Table
      Removed sentence which incorrectly stated that OpenType fonts that include CFF data must set numberOfHMetrics equal to the number of glyphs in the font.
    • 'post' Table
      Updated content related to glyph names in the post table.
    • 'OS/2' Table
      Added section on sTypoAscender, sTypoDescender, sTypoLineGap.
    • General Recommendations
      Updated the table ordering list for OpenType fonts containing CFF data by adding the 'maxp' table; and, removing the 'fvar' and 'MMSD' tables.
    • Baseline to Baseline Distances
      Added a paragraph on the recommended use of sTypoAscender, sTypoDescender, and sTypoLineGap.
    • OpenType CJK Font Guidelines
      This new section added.
  • ttochap1.htm
    • Introduction
      Removed 'MMSD' reference.
      Expanded the brief description of the content of Registered OpenType Layout Tags to reflect all OpenType tags: scripts, languages, baselines, features.
    • How Multiple Master OpenType Fonts Use OpenType Layout Tables
      This section removed.
  • ttoreg.htm
    • Added links in the introduction section, to help jump to the script, language, baseline and feature tag sections.
    • Script tags
      Corrected script tag length description.
      Added newer script tags.
    • Language system tags
      Added newer language tags.
    • Baseline tags
      Added newer baseline tags: "icfb", "icft" and "idtp". Expanded the description of existing tags into two categories: “Baseline for HorizAxis” and “Baseline for VertAxis”.
    • Ideographic Em-Box
      This new section added.
    • Ideographic Character Face
      This new section added.
  • vhea.htm
    • Introduction
      Added a link each for the vmtx table and the CJK guidelines section.
    • table.version.description
      Version number increased to 1.1. Added a note to indicate the difference in representing the fractional part of a version number when it is non-zero.
    • table.ascent
      Replaced by vertTypoAscender.
    • table.descent
      Replaced by vertTypoDescender.
    • table.lineGap
      Replaced by vertTypoLineGap.
    • Vertical Header Table Example
      Changed version value to 1.1. Corrected the name for vertTypoLineGap
  • vmtx.htm
    • Introduction
      Added a link for accessing the CJK guidelines section.
    • Vertical Origin and Advance Height
      This new section added.
    • Vertical Metrics Table Format
      Added note on the calculating the top side bearing.
  • vorg.htm
    • This new table added. This is needed by CFF OpenType fonts to locate the origin of vertical glyphs.
  • wgl4d.htm
    • Added a missing asterisk for PostScriptName.macron
    • Added the U+02dc (tilde)-- was missing from the list.

Version 1.4 - released 11 October 2002

Summary of Changes:

  • baselinetags.htm
    • Corrected typographic error.
    • Changed hanging baseline references from Hindi to Tibetan.
  • chapter2.htm
    • Corrected link to GDEF table.
    • Add documentation on new script tag 'DFLT'.
  • cmap.htm
    • Add Name column to tabular data to make consistent with other parts of spec.
    • Correct description of Encoding Record.
  • cvt.htm
    • Indicate that length must be integral value of FWORD units.
  • default.htm
    • Update the version number to 1.4.
    • Removed mention of Microsoft Word documents. (Post-release update, August 2018.)
  • dsig.htm
    • Provide information for ulVersion to be 0x00000001.
    • Update to show usFlag bits that are assigned.
    • Add section on signatures for TrueType Collections.
  • ebdt.htm
    • Change wording to indicate 'EBDT' is superset of 'bdat'. These are not the same.
  • featurelist.htm
    • Added new features: abvf, c2pc, ljmo, nlck, pcap, pref, rtla, tjmo, unic, and vjmo.
    • Change friendly name of 'calt' from Connection Forms to Contextual Alternates.
  • fpgm.htm
    • Add comment that array size n is the number of bytes in the table.
  • gdef.htm
    • Example 6, typos in the comments column for increasing 15 and 16ppem corrected.
  • gpos.htm
    • Clarify origin of Cartesian coordinate system at baseline of the left side.
    • Specify all values are done in font unit measurements.
    • Update images for better presentation.
    • PairPosFormat1 subtable ValueRecord changed to Offset, PairSetOffset[PairSetCount].
    • Update wording on MarkToMark attachment.
  • grstate.doc
  • gsub.htm
    • Add Lookup Type 8, Reverse Chaining contextual single substitution.
  • hdmx.htm
    • Remove references to EGA.
    • Add statement that bit 2 of head.flag must be set to 1.
    • Add Name columns to tabular data for consistency with spec.
  • head.htm
    • Updated macStyle bit descriptions for bits 2 to 15.
    • unitsPerEm annotated that it should be a power of 2.
  • hhea.htm
    • Change FWord to FWORD for correct data type spelling.
  • ibmfc.htm
    • Fix formatting to indent subclasses for better readability.
  • instgly.doc
  • name.htm
    • Add Name column to tabular data for consistency with spec.
    • Correct descriptions in Naming Table for count and nameRecord[count].
    • Clarified description of encoding ID 0/3. Added encoding ID 0/4. Changed description of encoding ID 3/10 to UTF-32.
    • Added description and example, for use of name ID 4 in CFF fonts.
    • Clarified working for use of name ID 5 (Version string).
    • Changed wording for name ID 16 (Preferred Family) and name ID 17 (Preferred Subfamily).
    • Suggest that style strings (name ID 2 or 17) match with OS/2.usWeightClass and OS/2.usWidthClass.
  • os2.htm
    • Updated version number to 0x0003
    • Updated Unicode sub-range bits to be aligned with Unicode 3.2.
    • Remove weighted calculation of xAvgCharWidth.
    • Make fsType bits 0-3 to be mutually exclusive. In other words, only one of those bits may be set to “1” at a time. This is to avoid problems of ambiguity in what the font designer intends.
    • Change link to PANOSE specification.
    • Updated description of usFirstCharIndex, usLastCharIndex, usDefaultChar, usBreakChar; in context of fonts that provide surrogate character support.
    • Corrected link to PANOSE specification. (Post-release update, September 2018.)
  • os2ver0.htm
    • Corrected link to PANOSE specification. (Post-release update, September 2018.)
  • os2ver1.htm
    • Corrected link to PANOSE specification. (Post-release update, September 2018.)
  • os2ver2.htm
    • Corrected link to PANOSE specification. (Post-release update, September 2018.)
  • otff.htm
    • Update filename information for TrueType outline fonts.
    • Add data types for FWORD and UFWORD.
    • Corrected content and description of TTC header v1 and v2.
    • Moved VORG table to PostScript Outlines group.
  • pclt.htm
    • Change to discourage use of this table.
  • proposals.htm
    • Remove proposed feature tags that were incorporated into this version.
  • recom.htm
    • Added recommendation for first four glyphs in font.
    • Added recommendation for shape of .notdef glyph.
    • Corrected link to PANOSE specification. (Post-release update, September 2018.)
  • scripttags.htm
    • Add script tags for Byzantine Music and Default.
  • ttinst.htm
    • Revised links to refer to content ported from Microsoft Word files to Web pages. (Post-release update, August 2018.)
  • ttinst1.doc
  • ttinst2.doc
    • Corrected description in Logical_Functions.Greater_Than.
    • Content ported into Web page: tt_instructions.htm. (Post-release update, August 2018.)
  • ttoreg.htm
    • Reworded and reorganized for better readability.
  • vdmx.htm
    • Change ratio record and vTable record to tabular format.
    • Recommend use of version 1 vdmx.
  • wgl4e.htm
    • Optional glyphs identified and marked. Added a footnote.