Editing OpenType (section)

=== Font Variations ===
{{See also|Variable fonts}}
On September 14, 2016, Microsoft announced the release of OpenType version 1.8. This announcement was made together with Adobe, Apple, and Google at the [[ATypI]] conference in Warsaw.<ref>Archived at [https://ghostarchive.org/varchive/youtube/20211211/M-vdFRtcZU0 Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20170811192129/https://www.youtube.com/watch?v=M-vdFRtcZU0&feature=youtu.be Wayback Machine]{{cbignore}}: {{cite web |url=https://www.youtube.com/watch?v=M-vdFRtcZU0 |title=Special OpenType Session |website=[[YouTube]] |date=2016-09-14 |access-date=2017-04-22}}{{cbignore}}</ref> OpenType version 1.8 introduced "OpenType Font Variations", which adds mechanisms that allow a single font to support many design variations.<ref>{{cite web |url=https://medium.com/@tiro/https-medium-com-tiro-introducing-opentype-variable-fonts-12ba6cd2369 |title=Introducing OpenType Variable Fonts |author=John Hudson |access-date=2017-04-22}}</ref> Fonts that use these mechanisms are commonly referred to as "[[OpenType variable fonts|Variable fonts]]".

OpenType Font Variations re-introduces techniques that were previously developed by Apple in [[Apple Advanced Typography|TrueType GX]], and by Adobe in [[Multiple master fonts|Multiple Master fonts]]. The common idea of these formats is that a single font includes data to describe multiple variations of a glyph outline (sometimes referred to as "masters"), and that at text-display time, the font rasterizer is able to interpolate or "blend" these variations to derive a continuous range of additional outline variations.<ref name=ots-var>{{cite web |url=https://learn.microsoft.com/en-us/typography/opentype/spec/otvaroverview |title=OpenType Font Variations Overview |department=Microsoft Typography |website=[[Microsoft Learn]] |access-date=2024-04-13}}</ref>

The concept of fully parametric fonts had been explored in a more general way by [[Donald Knuth|Donald E. Knuth]] in the [[Metafont|METAFONT]] system, introduced in 1978.<ref>Knuth, Donald E. Mathematical typography. Bull. Amer. Math. Soc. (N.S.) 1 (1979), no. 2, 337--372.https://projecteuclid.org/euclid.bams/1183544082</ref> That system and its successors were never widely adopted by professional type designers or commercial software systems.<ref>CSTUG, Charles University, Prague, March 1996, Questions and Answers with Prof. Donald E. Knuth, reproduced in TUGboat '''17 (4)''' (1996), 355–67. Citation is from page 361. Available online at http://www.tug.org/TUGboat/Articles/tb17-4/tb53knuc.pdf</ref> TrueType GX and Multiple Master formats, OpenType Font Variations' direct predecessors, were introduced in the 1990s, but were not widely adopted, either. Adobe later abandoned support for the Multiple Master format.<ref>{{Cite web |url=https://blog.typekit.com/2014/07/30/the-adobe-originals-silver-anniversary-story-how-the-originals-endured-in-an-ever-changing-industry/ |title=The Adobe Originals Silver Anniversary Story: How the Originals endured in an ever-changing industry |author=Tamye Riggs |date=2014-07-30 |access-date=2017-04-22}}</ref> This has led to questions as to whether a re-introduction of similar technology could succeed. By 2016, however, the industry landscape had changed in several respects. In particular, emergence of Web fonts and of mobile devices had created interest in [[Responsive web design|responsive design]] and in seeking ways to deliver more type variants in a size-efficient format. Also, whereas the 1990s was an era of aggressive competition in font technology, often referred to as "the font wars",<ref>{{Cite web |last=Shimada |first=James |date=2006-12-06 |url=https://courses.cs.washington.edu/courses/csep590/06au/projects/font-wars.pdf |title=The Font Wars |access-date=2021-12-14}}</ref><ref>{{Cite web |url=https://www.britannica.com/topic/Adobe-Systems-Incorporated#ref663628 |title=Adobe Inc. |website=[[Encyclopædia_Britannica|Britannica]] |at=Font Wars |access-date=2022-04-10}}</ref><ref>{{Cite book |last=Cringely |first=Robert X. |author-link=Robert X. Cringely |date=1996 |title=[[Accidental Empires]] |edition=Revised and updated |publisher=[[Penguin Books]] |chapter=Font Wars |chapter-url=https://www.cringely.com/2013/03/14/accidental-empires-chapter-11-font-wars/ |pages=209–229 |isbn=0-14-025826-4}}</ref> OpenType Font Variations was developed in a collaborative manner involving several major vendors.<ref>{{Cite web |url=https://www.pastemagazine.com/articles/2017/01/the-font-wars.html |title=The Font Wars |author=David Lemon |date=2017-01-27 |access-date=2017-04-22}}</ref>

Font Variations is integrated into OpenType 1.8 in a comprehensive manner, allowing most previously-existing capabilities to be used in combination with variations. In particular, variations are supported for both TrueType or CFF glyph outlines, for TrueType hinting, and also for the OpenType Layout mechanisms. The only parts of OpenType for which variations are not supported but might potentially be useful are the 'SVG ' table for color glyphs, and the MATH table for layout of mathematical formulas. The 'SVG ' table uses embedded XML documents, and no enhancement for variation of graphic elements within the SVG documents has been proposed. However, enhancement to the COLR table in OpenType 1.9 has provided a vector format for color glyphs with support for variations.<ref name=ots-colr-vars>{{Cite web |url=https://learn.microsoft.com/en-us/typography/opentype/spec/colr#colr-table-and-opentype-font-variations |title=COLR — Color Table § COLR table and OpenType Font Variations |department=Microsoft Typography |website=[[Microsoft Learn]] |access-date=2024-04-13}}</ref>

OpenType 1.8 made use of tables originally defined by Apple for TrueType GX (the avar, cvar, fvar and gvar tables). It also introduced several new tables, including a new table for version 2 of the CFF format (CFF2), and other new tables or additions to existing tables to integrate variations into other parts of the font format (the HVAR, MVAR, STAT and VVAR tables; additions to the BASE, GDEF and name tables).<ref name=ots-changes />