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Generation of Characters

IP.com Disclosure Number: IPCOM000049062D
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Beaven, PA: AUTHOR [+2]

Abstract

The conventional method of generating a pel (picture element) representation of a character is to store the horizontal scans (slices) of the character in a read-only store (ROS). Hence, by presenting the ROS address with a character code (typically 8 bits) and a slice code (typically 4 bits) a character slice is obtained. A consequence of this method of character generation is that if different characters have common slice patterns, the common pattern may be repeated many times in the ROS. The idea described here uses a different memory organization in place of the ROS, with the object of reducing the amount of redundantly stored information.

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Generation of Characters

The conventional method of generating a pel (picture element) representation of a character is to store the horizontal scans (slices) of the character in a read-only store (ROS). Hence, by presenting the ROS address with a character code (typically 8 bits) and a slice code (typically 4 bits) a character slice is obtained. A consequence of this method of character generation is that if different characters have common slice patterns, the common pattern may be repeated many times in the ROS. The idea described here uses a different memory organization in place of the ROS, with the object of reducing the amount of redundantly stored information.

The drawing shows the new character generator which uses three sub arrays, a character array, a slice array and an output array. If character N, slice M has the pattern 000111000, the memory is written as shown, the output being selected when a horizontal coincidence is detected between a 1 in the character and slice arrays. The output data is the 'vertical 0R compression' of all selected rows; hence, several rows may contribute to a character slice.

Because any character can select a given horizontal line (by being written with a 1 in the character array) the same slices of different characters can share the same slice pattern. Also different slices of the same character can share the same slice pattern.

The vertical dimension X of the array is a function not of the number of characters in the chara...