Fallback font
From Wikipedia, the free encyclopedia
A fallback font is a reserve typeface containing symbols for all Unicode characters. When a display system encounters a character which is not part of the repertoire of any of the other available fonts, a symbol from a fallback font is used instead. Typically, a fallback font will contain symbols representative of the various types of Unicode characters. The use of a fallback font is suggested in The Unicode Standard.
Systems that do not offer a fallback font typically display black or white rectangles, question marks, or nothing at all in place of missing characters. Symbols in a fallback font can contain annotations such as the relevant Unicode block and the script system used.
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[edit] Apple's LastResort font
LastResort is a Mac OS font that is invisible to the end user, but is used by the system to display glyphs that are not available in any other font. The symbols provided by LastResort place glyphs into categories based on their location in the Unicode system and provide a hint to the user about which font or script is required to view the unavailable characters. The symbols provided by LastResort are square with rounded corners with a bold outline. In the left and right sides of the outline, the Unicode range that the character belongs to is given using hexadecimal digits. Top and bottom are used for one or two descriptions of the Unicode block. A symbol representative of the block is centered inside the square.
Apple's LastResort font was first included in Mac OS 8.5, for the benefit of applications using Apple Type Services for Unicode Imaging. It is also used in Mac OS X. Last Resort was designed by Michael Everson of Evertype.
[edit] The Unicode BMP Fallback font
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The Unicode BMP Fallback font is a Unicode font containing a glyph for every character in the Basic multilingual plane. Each glyph consists of a box containing the four hex digits corresponding to the Unicode value. The example to the left is a mock-up of the glyph for a space character (U+0020).
The font was created for debugging purposes.
[edit] See also
[edit] References
- Apple Computer (November 2, 2002). Apple's LastResort font web site. Retrieved 2004-11-02.
- The Unicode Consortium (March 30, 2004). The Unicode Standard, 4.0.1. Retrieved 2004-11-02.
- Description of the Unicode BMP fallback font at SIL International
[edit] External links
- [1] -- Apple Computer on Last Resort
- [2] -- brief discussion of Last Resort by Michael Everson
- SIL International's Unicode BMP Fallback Font — Free fallback font
