The font Top Level Type
Network Working Group C. Lilley
Intended status: Standards Track January 29, 2016
Expires: August 1, 2016
The font Top Level Type
This memo serves to register and document the "font" Top Level Type,
under which the Internet Media subtypes for representation formats
for fonts may be registered. This document also serves as a
registration application for a set of intended subtypes, which are
representative of some existing subtypes already registered under the
"application" tree by their separate registrations.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on August 1, 2016.
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Internet-Draft The font Top Level Type January 2016
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The process of setting type in computer systems and other forms of
text presentation systems uses fonts in order to provide visual
representations of the glyphs. Just as with images, for example,
there are a number of ways to represent the visual information of the
glyphs. Early font formats often used bitmaps, as these could have
been carefully tuned for maximum readability at a given size on low-
resolution displays. More recently, scalable vector outline fonts
have come into widespread use: in these fonts, the outlines of the
glyphs are described, and the presentation system renders the outline
in the desired position and size.
This document defines a top-level Internet Media Type type "font"
under which different representation formats of fonts may be
registered (e.g. a bitmap or outline formats). It should be
emphasized that, just as under the "image" top-level type one does
not find registration for a specific image, for example, "The Night-
watch" (by Rembrandt) but instead "JPEG" (a compressed image data
representation format), so, under "font" one will not find "Courier"
(the name of a popular font) but perhaps "TTF", "OTF" or "SFNT" (the
names of commonly used TrueType and OpenType font formats as well as
their higher-level wrapper format).
2. Background and Justification
Historically there has not been a registration of formats for fonts.
Most recently, there have been several representation formats
registered as MIME subtypes under the "application" top-level type.
However, with the rapid adoption of web fonts (based on the data from
HTTP Archive  showing a huge increase in web font usage from 1% in
the end of 2010 to 50% across all sites in the beginning of 2015)
custom fonts on the web have become a core web resource. As the in-
depth analysis  shows, the lack of the intuitive top-level font
type is causing significant confusion among developers - while
currently defined font subtypes are severely under-utilized there are
many more sites that already use non-existent (but highly intuitive)
media types such as "font/woff", "font/ttf" and "font/truetype". At
the same time, the majority of sites resort to using generic types
such as "application/octet-stream", "text/plain" and "text/html"; or
use unregistrable types such as "application/x-font-ttf".
Contrary to our expectations, the officially defined IANA subtypes
such as "application/font-woff" and "application/font-sfnt" see a
very limited use - their adoption rates trail far behind as the
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