The OpenType™ specification has been formatted in HTML, but may link to .PDF files.
OpenType specification version 1.8.1
- OpenType overview
- The OpenType font file
- Font file tables
- Advanced typographic extensions (OpenType Layout)
- OpenType Layout Common Table Formats
- OpenType Font Variations Overview
- OpenType Font Variations Common Table Formats
- OpenType Layout Tag Registry
- The WGL4.0 character set
- TrueType fundamentals
- The TrueType instruction set
- OpenType Mirroring Pairs List
- Adobe technical note #5176: “The Compact Font Format Specification.”
- Adobe technical note #5177: “Type 2 CharString Format.”
- The CFF2 CharString Format
- Adobe Technical Note #5902: “PostScript Name Generation for Variation Fonts”
- Specification changes log file
OpenType 1.8.1 incorporates revisions in Amendment 1 and Draft Amendment 2 of the ISO/IEC 14496-22:2015 “Open Font Format (3rd edition)” standard. Additionally, it incorporates extensions not included in ISO/IEC 14496-22:2015 plus Amendments 1 and 2: the 'MERG', 'meta' and 'sbix' tables, and all of the addtions related to OpenType Font Variations. Current editions and amendments of ISO/IEC 14496-22 are freely available for download from the ISO website.
Updates to this specification are noted in the change log.