SFNT

SFNT

Filename extension	.ttf .otf[1]
Internet media type	font/sfnt application/font-sfnt (deprecated) [2]

SFNT is a font file format which can contain other fonts, such as PostScript, TrueType, OpenType, Web Open Font Format (WOFF) fonts. SFNT stands for spline font or scalable font, and was originally developed for TrueType fonts on the Macintosh and used by Apple Computer's QuickDraw.^[3] SFNT was named after the resource tag the Macintosh used internally to track font data.

Many existing font formats are based on the table-based SFNT format, such as TrueType, OpenType and Open Font Format, Web Open Font Format (WOFF), SIL Graphite and many others.

SFNT is flexible, extensible and offers an opportunity to introduce additional table structures when needed, in a way that would not affect existing font rendering engines and text layout implementations.^[1] However, due to the limitation of SFNT system, a maximum number of 16⁴ = 65536 characters can be put in one font table.^[4] This limitation is partially overcome in the derived formats using "OpenType Collections", formerly known as "TrueType collections", so that a file can contain multiple fonts with up to 65536 characters.

See also

• Web typography

References

1. "Font-SFNT". Internet Assigned Numbers Authority. 29 March 2013. Archived from the original on 4 April 2023. Retrieved 20 June 2023.
2. "Media Types". IANA. 12 October 2017. Retrieved 17 October 2017.
3. "The 'sfnt' format". Apple Developer Connection. Apple. Archived from the original on 23 October 2013. Retrieved 18 October 2010.
4. "The TrueType Font File". Apple Developer. Retrieved 6 December 2018.