Browse Prior Art Database

Selective Page-Edge Control for Pseudo-Kerned Type Fonts

IP.com Disclosure Number: IPCOM000060017D
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 40K

Publishing Venue

IBM

Related People

Boulia, DI: AUTHOR [+3]

Abstract

Kerning is usually achieved using so-called kerning tables in certain applications for reducing programming overhead and facilitating higher speed printing. Certain type fonts are defined as having a central space and two peripheral, horizontal spaces. Kerning is achieved by making the peripheral spaces negative, i.e., so one character will be more closely spaced to the second character by overlaying some of the blank space of the other character. When the baseline margins are limited in certain printing applications, the negative space may extend beyond the edge of the page causing an over-edged extension of a character to be printed and, therefore, a truncation of the characters with a reduction in typographic quality.

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Selective Page-Edge Control for Pseudo-Kerned Type Fonts

Kerning is usually achieved using so-called kerning tables in certain applications for reducing programming overhead and facilitating higher speed printing. Certain type fonts are defined as having a central space and two peripheral, horizontal spaces. Kerning is achieved by making the peripheral spaces negative, i.e., so one character will be more closely spaced to the second character by overlaying some of the blank space of the other character. When the baseline margins are limited in certain printing applications, the negative space may extend beyond the edge of the page causing an over-edged extension of a character to be printed and, therefore, a truncation of the characters with a reduction in typographic quality. This disclosure teaches accommodation of such over-edge extension by tightening the character spacing along the baseline by pulling in the over-edge extension into the confines of the page. All-points-addressable printers, video display terminals, and the like, are capable of using proportionally-spaced typographic fonts. The characters in the fonts include spacing characteristics along the baseline (hereinafter referred to as "horizontal spacing") which include A, B, and C baseline spacing values, as shown in the figure. The B space, or the central space, is the baseline placement occupied by a central portion of the characters. The A and C spaces are peripheral spaces. When the A and C spaces are positive, the baseline displacement for A and C is added to the B displacement as shown in the AA portion of the figure. Therefore, when a line is printed, the characters are positioned such that the C space boundaries of a left character is immediately adjacent and abuts the A space boundary of a character to its immediate right. In certain character combinations, especially in the italicized fonts, the result is that there is aesthetically too much space between the characters along the baseline. Kerning is a typical approach for decreasing the intercharacter spacing for enhancing font aesthetics. Kerning is merely overlapping the character by either repositioning the characters or by using negative A and C peripheral space values, i.e., pseudo kerning as shown in the figure illustrating the italicized letters "ff". By appropriately selecting negative A and C values, significant kerning, or overlap, is achieved as shown in the pseudo-kerning figure. The negative A space associated wit...