A variable font (VF) is a font file that is able to store a continuous range of design variants. An entire

typeface A typeface (or font family) is the design of lettering that can include variations in size, weight (e.g. bold), slope (e.g. italic), width (e.g. condensed), and so on. Each of these variations of the typeface is a font. There are thousands o ...

(font family) can be stored in such a file, with an infinite number of

font In metal typesetting, a font is a particular size, weight and style of a typeface. Each font is a matched set of type, with a piece (a " sort") for each glyph. A typeface consists of a range of such fonts that shared an overall design. In mo ...

s available to be sampled. The variable font technology originated in Apple's

TrueType GX QuickDraw GX was a replacement for the QuickDraw (QD) 2D graphics engine and Printing Manager inside the classic Mac OS. Its underlying drawing platform was a resolution-independent object oriented retained mode system, making it much easier for ...

font variations. The technology was adapted to

OpenType OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior. OpenType is a registered trademark ...

as OpenType variable fonts (OTVF) in version 1.8 of the OpenType specification. The technology was announced by

Adobe Adobe ( ; ) is a building material made from earth and organic materials. is Spanish for '' mudbrick''. In some English-speaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of ...

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancest ...

, Google, and

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...

in September 2016. Making such a feature standardized in OpenType paved the way for support in many software platforms.

Technology

OpenType variable fonts are an adaptation of Apple's

font variations to OpenType, with integration into key aspects of the OpenType format including OpenType Layout tables and both

TrueType TrueType is an outline font standard developed by Apple in the late 1980s as a competitor to Adobe's Type 1 fonts used in PostScript. It has become the most common format for fonts on the classic Mac OS, macOS, and Microsoft Windows operating ...

and CFF glyph outline formats. It also surpasses TrueType GX by providing better interoperability, both between different fonts, and between variable fonts and font-formatting specifications such as those found in

Cascading Style Sheets Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language such as HTML or XML (including XML dialects such as SVG, MathML or XHTML). CSS is a cornerstone tec ...

. The technology allows software to access any design instance for a continuous range of designs defined within the font. When a specific design instance has been selected, the glyph outlines or other data values for that design instance are computed as font data is being processed during text layout and rasterization. The technology uses interpolation and extrapolation mechanisms that have been supported in font-development tools and used by font designers for many years. In that paradigm, the font designer creates a variable design, but then chooses specific instances to generate as static, non-variable fonts that get distributed to customers. With variable fonts, however, the font produced and distributed by the font designer can have built-in variability, and the interpolation mechanisms can now be built into operating systems and Web browsers or other applications, with specific design instances selected at time of use. One of the key benefits of the technology is that it can significantly reduce the combined size of font data whenever multiple styles are in use. On the Web, this may allow a site to use more font styles while at the same time reducing page load times. A further benefit is that it gives access to a continuous range of style variations, which can provide benefits for responsive design. The technology has been compared to Adobe's multiple master fonts (MM fonts) technology, also from the 1990s, which used on-the-fly generation of font designs from master files by interpolation and extrapolation. Multiple master fonts, however, required the user to generate a specific "instance" of the font for particular variation-axis values before it could be used. This is not required for OpenType variable fonts, however: named or arbitrary design instances can be selected and used on demand.

Adoption

Operating systems

Windows 10 Windows 10 is a major release of Microsoft's Windows NT operating system. It is the direct successor to Windows 8.1, which was released nearly two years earlier. It was released to manufacturing on July 15, 2015, and later to retail on ...

, version 1709, Microsoft introduced the first variable font in Windows: the "Bahnschrift" font, which is a digitisation of DIN 1451. FreeType, the font rendering program used by most

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

systems including

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...

, received variable font support in May 2017 (FreeType 2.8).

Editors

Adobe Creative Cloud 2018 version, released 18 October 2017, includes support for variable fonts in

Photoshop Adobe Photoshop is a raster graphics editor developed and published by Adobe Inc. for Windows and macOS. It was originally created in 1988 by Thomas and John Knoll. Since then, the software has become the industry standard not only in raster ...

and

Illustrator An illustrator is an artist who specializes in enhancing writing or elucidating concepts by providing a visual representation that corresponds to the content of the associated text or idea. The illustration may be intended to clarify complic ...

and includes variable concept versions of the fonts Acumin, Minion,

Myriad A myriad (from Ancient Greek grc, μυριάς, translit=myrias, label=none) is technically the number 10,000 (ten thousand); in that sense, the term is used in English almost exclusively for literal translations from Greek, Latin or Sinospher ...

Source Code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the ...

, Source Sans, and Source Serif. Creative Cloud 2020 has added variable font support for InDesign.

Inkscape Inkscape is a free and open-source vector graphics editor used to create vector images, primarily in Scalable Vector Graphics (SVG) format. Other formats can be imported and exported. Inkscape can render primitive vector shapes (e.g. rec ...

version 1.0 has added variable font support.

Browsers

Variable fonts are controlled in the

web browser A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used o ...

using both existing properties for well-known options such as weight and a raw control. Refer to the MDN pages of the CSS property for support history.

References

{{Reflist

External links

From TrueType GX to Variable FontsV-Fonts
a showcase of available variable fonts by Nick Sherman
Variable fonts guideVariable Fonts on the WebVariable Fonts: the Future of (Web) Type
Adobe Inc. Font formats Computer-related introductions in 2016 Typesetting