Embedded OpenType (EOT)

fonts In movable type, metal typesetting, a font is a particular #Characteristics, 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) inclu ...

are a compact form of

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 ...

fonts designed by

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 ...

for use as embedded fonts on

web page A web page (or webpage) is a World Wide Web, Web document that is accessed in a web browser. A website typically consists of many web pages hyperlink, linked together under a common domain name. The term "web page" is therefore a metaphor of pap ...

s. These files use the extension .eot. They are supported only by

Microsoft Internet Explorer Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated as IE or MSIE) is a retired series of graphical web browsers developed by Microsoft that were used in the Windows line of operating ...

, as opposed to competing WOFF files.

Overview

EOT font files can be created from existing

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 ...

font files using Microsoft's Web Embedding Fonts Tool (WEFT), and other proprietary and open source software (see “External links” below). The font files are made small in size by use of

subsetting In research communities (for example, earth sciences, astronomy, business, and government), subsetting is the process of retrieving just the parts (a subset) of large files which are of interest for a specific purpose. This occurs usually in a clien ...

(only including the needed characters), and by

data compression In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compressi ...

(LZ compression, part of

Agfa Agfa-Gevaert N.V. (Agfa) is a Belgian-German multinational corporation that develops, manufactures, and distributes Analog photography, analogue and digital imaging products, software, and systems. The company began as a dye manufacturer in 1867 ...

'
MicroType Express
. Like OTF fonts, EOT supports both Postscript and TrueType outlines for the glyphs. Simply including fonts in webpages might lead to unrestricted copying of copyrighted font files. Embedded OpenType includes features to discourage copying. Subsetting reduces the value of copying, as subsetted fonts will typically omit more than half of the characters. Other copy protection measures used are

encryption In Cryptography law, cryptography, encryption (more specifically, Code, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the inf ...

and a list of "trusted roots" at the source end, and a proprietary decrypting library at the receiving end. If the embedded font is not available to the web page for any reason (missing font file, wrong keys in the file, non-support by the web browser), then the second-choice font specification is used, ensuring that the page should be readable even without the intended font. Embedded OpenType is a proprietary standard supported exclusively by

Internet Explorer Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated as IE or MSIE) is a deprecation, retired series of graphical user interface, graphical web browsers developed by Microsoft that were u ...

but wa
submitted to the W3C in 2007 as part of CSS3
which was rejected and resubmitted as
standalone submission March 18, 2008
Th
W3C team comment
on the submission states that the "W3C plans to submit a proposal to the W3C members for a working group whose goal is to try and develop EOT into a W3C Recommendation." However, the W3C ultimately chose a different web font format ( WOFF) as a W3C Recommendation. The support for the format has not been built into the

Microsoft Edge Microsoft Edge is a Proprietary Software, proprietary cross-platform software, cross-platform web browser created by Microsoft and based on the Chromium (web browser), Chromium open-source project, superseding Edge Legacy. In Windows 11, Edge ...

, the successor to the Internet Explorer.

Web Embedding Fonts Tool

The Web Embedding Fonts Tool, or WEFT, is

's utility for generating embeddable

web fonts Web typography, like typography generally, is the design of pages their layout and typeface choices. Unlike traditional print-based typography (where the page is fixed once typeset), pages intended for display on the World Wide Web have additional ...

. WEFT is used by webmasters to create 'font objects' that are linked to their

s so that users using Microsoft's

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 ...

will see the pages displayed in the font style contained within the font object. WEFT scans the

HTML Hypertext Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It defines the content and structure of web content. It is often assisted by technologies such as Cascading Style Sheets ( ...

document file(s), the TrueType font file(s), and some additional parameters. It adjusts the HTML files and creates Embedded OpenType files for inclusion on the web site. These files usually use the extension '.eot'. WEFT can embed most fonts, but it will not embed fonts that have been designated as 'no embedding' fonts by their designers. WEFT may reject other fonts because problems have been identified. In the past, embedded fonts were widely used to generate non-English-language websites. As of January 2015, the most recent version of the tool (WEFT 3.2) was released on 25 February 2003. As of 2019, the tool is no longer offered by Microsoft for download. An open source alternative is
ttf2eot
. Microsoft PowerPoint 2007 and 2010 also generate .eot files with the '.fntdata

extension when fonts are selected to be embedded in a presentation by the PowerPoint client application. These .eot files can be extracted from the '.pptx' file and used directly on web pages.

Security issues

Critical security update for

Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, released five years earlier, which was then the longest time span between successive releases of Microsoft W ...

KB969947 resolves several security issues that "could allow remote code execution if a user viewed content rendered in a specially crafted Embedded OpenType (EOT) font". Such fonts could be embedded in Web sites, including those that host user-provided content.

References

External links

Microsoft Typography - Font Embedding for the WebMicrosoft Typography - Web Embedding Fonts ToolEOT-utils
– open-source free software to make EOT fonts by W3C
ttf2eot
– open-source free software to convert font from TTF to EOT
Compatibility table for support of EOT fonts in browsersW3C Submission describing the formatMinutes of the W3C Fonts Working Group, 23 October 2008MIME registrationGoogle Web Fonts
{{Typography terms Font formats

Overview

Web Embedding Fonts Tool

Security issues

See also

References

External links