A variable font (VF) is a

font file A computer font is implemented as a digital data file containing a set of graphically related glyphs. A computer font is designed and created using a font editor. A computer font specifically designed for the computer screen, and not for print ...

that is able to store a continuous range of design variants. An entire

typeface A typeface (or font family) is a design of Letter (alphabet), letters, Numerical digit, numbers and other symbols, to be used in printing or for electronic display. Most typefaces include variations in size (e.g., 24 point), weight (e.g., light, ...

(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'', defined as the set of fonts that share an overall design. For instance, the typeface Bauer Bodoni (shown in the figure) includes fonts " Roman" (or "regul ...

s available to be sampled. The variable font technology originated in Apple's TrueType GX font variations. The technology was adapted to

OpenType OpenType is a format for scalable computer fonts. Derived from TrueType, it retains TrueType's basic structure but adds many intricate data structures for describing typographic behavior. OpenType is a registered trademark of Microsoft Corpora ...

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

Adobe Adobe (from arabic: الطوب Attub ; ) 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 use ...

Apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

Google Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial ...

, and

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

in September 2016. Making such a feature standardized in OpenType paved the way for support in many software platforms. Variable fonts should not be confused with variable-width fonts. A variable font may be either variable-width or fixed-width.

Technology

OpenType variable fonts are an adaptation of Apple's TrueType GX font variations to OpenType, with integration into key aspects of the OpenType format including OpenType Layout tables and both

TrueType TrueType is an Computer font#Outline fonts, outline font standardization, standard developed by Apple Inc., Apple in the late 1980s as a competitor to Adobe Inc., Adobe's PostScript fonts#Type 1, Type 1 fonts used in PostScript. It has become the ...

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. 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 Multiple master fonts (or MM fonts) are an extension to Adobe Systems' Type 1 PostScript fonts, now superseded by the advent of OpenType and, in particular, the introduction of OpenType Font Variations in OpenType 1.8, also called variable 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, version 1709 Windows 10 Fall Creators Update (also known as version 1709 and codenamed "Redstone 3") is the fourth major update to Windows 10 and the third in a series of updates under the Redstone codenames. It carries the build number 10.0.16299. PC versio ...

(or known as "

Windows 10 Windows 10 is a major release of Microsoft's Windows NT operating system. The successor to Windows 8.1, it was Software release cycle#Release to manufacturing (RTM), released to manufacturing on July 15, 2015, and later to retail on July 2 ...

Fall Creators Update") released in 2017, official support for variable fonts is provided by Microsoft, along with the first variable font in Windows: the "Bahnschrift" font, which is a digitisation of

DIN 1451 DIN 1451 is a sans-serif typeface that is widely used for traffic, administrative and technical applications. It was defined by the German standards body DIN (, 'German Institute for Standardisation', pronounced like the English word ''din'') in ...

. However, support for CFF2 fonts using OpenType outlines had caused issues with Windows text rendering engine, sometimes making UI text blank out; this was later fixed in 2023 with the KB5032278 update. Android started to provide variable font support for mobile app developers in Android Oreo or API level 26.

provided variable font support in its operating system since

macOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

10.5/ iOS 3.2, but usage in

Safari A safari (; originally ) is an overland journey to observe wildlife, wild animals, especially in East Africa. The so-called big five game, "Big Five" game animals of Africa – lion, African leopard, leopard, rhinoceros, African elephant, elep ...

through

WebKit WebKit is a browser engine primarily used in Apple's Safari web browser, as well as all web browsers on iOS and iPadOS. WebKit is also used by the PlayStation consoles starting with the PS3, the Tizen mobile operating systems, the Amazon K ...

only comes in macOS 10.13/iOS 11 with Safari 11. FreeType, the font rendering program used by most

Unix-like A Unix-like (sometimes referred to as UN*X, *nix 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 Uni ...

systems including

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

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

Editors

Adobe Creative Cloud Adobe Creative Cloud is a set of applications and services from Adobe Inc., Adobe that gives subscribers access to a collection of software used for graphic design, video editing, web development, photography, along with a set of mobile applicat ...

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 for Windows and macOS. It was created in 1987 by Thomas and John Knoll. It is the most used tool for professional digital art, especially in raster graphics editin ...

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 complicate ...

and includes variable concept versions of the fonts Acumin,

Minion Minion or Minions may refer to: Places *Minions, Cornwall, a village in the United Kingdom People *Frank Minion (born 1929), American jazz and bop singer *Fred Minion, English professional footballer *Joseph Minion (born 1957), American film ...

Myriad In the context of numeric naming systems for powers of ten, myriad is the quantity ten thousand ( 10,000). Idiomatically, in English, ''myriad'' is an adjective used to mean that a group of things has indefinitely large quantity. ''Myriad ...

Source Code In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer. Since a computer, at base, only ...

, Source Sans, and

Source Serif Source Serif (known as Source Serif Pro before 2021) is a serif typeface created by Frank Grießhammer for Adobe Systems. It is the third open-source font family from Adobe, distributed under the SIL Open Font License. The typeface is inspired ...

. Creative Cloud 2020 has added variable font support for

InDesign Adobe InDesign is a desktop publishing and page layout designing software application produced by Adobe and first released in 1999. It can be used to create works such as posters, flyers, brochures, magazines, newspapers, presentations, books ...

Inkscape Inkscape is a vector graphics editor. It is used for both artistic and technical illustrations such as cartoons, clip art, logos, typography, diagrams, and flowcharts. It uses vector graphics to allow for sharp printouts and renderings at ...

version 1.0 has added variable font support.

LibreOffice LibreOffice () is a free and open-source office productivity software suite developed by The Document Foundation (TDF). It was created in 2010 as a fork of OpenOffice.org, itself a successor to StarOffice. The suite includes applications ...

version 7.5 has added variable font support.

Browsers

Variable fonts are controlled in the

web browser A web browser, often shortened to browser, is an application 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 scr ...

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