This font supplies the text layout software with instructions to synthesize the fraction according to the Unicode rule described in this section. The fraction slash character (U+2044) has special behavior in the Unicode Standard: (section 6.2, Other Punctuation) > The standard form of a fraction built using the fraction slash is defined as > follows: any sequence of one or more decimal digits (General Category = Nd), > followed by the fraction slash, followed by any sequence of one or more > decimal digits. Such a fraction should be displayed as a unit, such as ¾. If > the displaying software is incapable of mapping the fraction to a unit, then > it can also be displayed as a simple linear sequence as a fallback (for > example, 3/4).
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Example of fraction slash use. This typeface (Apple Chancery) shows the synthesized common fraction on the left and the precomposed fraction glyph on the right as a rendering the plain text string “1 1⁄4 1¼”. Depending on the text environment, the single string “1 1⁄4” might yield either result, the one on the right through substitution of the fraction sequence with the single precomposed fraction glyph. A more elaborate example of fraction slash usage: plain text “4 221⁄225” rendered in Apple Chancery.
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If the fraction is to be separated from a previous number, > then a space can be used, choosing the appropriate width (normal, thin, zero > width, and so on). For example, 1 + ZERO WIDTH SPACE \+ 3 + FRACTION SLASH > \+ 4 is displayed as 1¾. By following this Unicode recommendation, text processing systems yield sophisticated symbols from plain text alone. Here the presence of the fraction slash character instructs the layout engine to synthesize a fraction from all consecutive digits preceding and following the slash.
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In the same situation a more complex engine may combine information from the font with its own rules to achieve its own idea of best rendering. To implement all recommendations of the Unicode specification, a text engine must be prepared to work with fonts of any level of sophistication, since contextual substitution and positioning rules do not exist in some font formats and are optional in the rest. The fraction slash is an example: complex fonts may or may not supply positioning rules in the presence of the fraction slash character to create a fraction, while fonts in simple formats cannot.
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The fraction slash is used between two numbers to indicate a fraction or ratio. Such formatting developed as a way to write the horizontal fraction bar on a single line of text. It is first attested in England and Mexico in the 18th century.. This notation is known as an online, solidus,. or shilling fraction.
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Nowadays fractions, unlike inline division, are often given using smaller numbers, superscript, and subscript (e.g., 23⁄43). This notation is responsible for the current form of the percent , permille , and permyriad signs, developed from the horizontal form which represented an early modern corruption of an Italian abbreviation of per cento.. Many fonts draw the fraction slash (and the division slash) less vertical than the slash. The separate encoding is also intended to permit automatic formatting of the preceding and succeeding digits by glyph substitution with numerator and denominator glyphs (e.g.
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Division is most often shown by placing the dividend over the divisor with a horizontal line, also called a vinculum, between them. For example, a divided by b is written as: :\frac ab This can be read out loud as "a divided by b" or "a over b". A way to express division all on one line is to write the dividend, then a slash, then the divisor, as follows: :a/b This is the usual way to specify division in most computer programming languages since it can easily be typed as a simple sequence of characters. A handwritten or typographical variation — which is halfway between these two forms — uses a solidus (fraction slash) but elevates the dividend and lowers the divisor, as follows: : Any of these forms can be used to display a fraction.
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