Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

The Display of Characters Using Gray Level Sample Arrays

IP.com Disclosure Number: IPCOM000128893D
Original Publication Date: 1980-Dec-31
Included in the Prior Art Database: 2005-Sep-20
Document File: 7 page(s) / 28K

Publishing Venue

Software Patent Institute

Related People

John E. Warnock: AUTHOR [+3]

Abstract

Character fonts on raster scanned display devices are usually represented by arrays of bits that are displayed as a matrix of black and white dots. This paper reviews -a filtering and sampling method as applied to characters for building multiple bit per pixel arrays. These arrays can be used as alternative character representations for use on devices with gray scale capability. Discussed in this paper are both the filtering algorithms that are used to generate gray scale fonts and some consequences of using gray levels for the representation of fonts including: 1. The apparent resolution of the display is increased when using gray scale fonts allowing smaller fonts to be used with higher apparent positional accuracy and readability. This is especially important when using low resolution displays. 2. Fonts of any size and orientation can be generated automatically from suitable high precision representations. This automatic generation removes the tedious process of "bit tuning" fonts for a given display. CR Categories: Categories: 8.2 Key words and phrases: computer graphics, fonts, gray-scale, raster displays, shading, anti-aliasing, convolution, character representation

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 15% of the total text.

Page 1 of 7

THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

The Display of Characters Using Gray Level Sample Arrays

John E. Warnock

CSI.-80-6 Nhy 1980

Abstract

Character fonts on raster scanned display devices are usually represented by arrays of bits that are displayed as a matrix of black and white dots. This paper reviews -a filtering and sampling method as applied to characters for building multiple bit per pixel arrays. These arrays can be used as alternative character representations for use on devices with gray scale capability. Discussed in this paper are both the filtering algorithms that are used to generate gray scale fonts and some consequences of using gray levels for the representation of fonts including:

1. The apparent resolution of the display is increased when using gray scale fonts allowing smaller fonts to be used with higher apparent positional accuracy and readability. This is especially important when using low resolution displays.

2. Fonts of any size and orientation can be generated automatically from suitable high precision representations. This automatic generation removes the tedious process of "bit tuning" fonts for a given display.

CR Categories: Categories: 8.2

Key words and phrases: computer graphics, fonts, gray-scale, raster displays, shading, anti- aliasing, convolution, character representation

XEROX PALO ALTO RESEARCH CENTER

3333 Coyote Hill Road / Palo Alto / California 94304

Introduction

The motivation behind the work presented in this paper comes from research into the problems of building an interactive display system that allows users to design high quality page layouts much like those found in advertising copy. To achieve this goal, the problem of displaying,a wide variety of different character fonts on an interactive display must be solved. It is important for this application that the characters on the interactive display reflect the shapes and styles that are to be in the final printed copy. The aesthetic judgments demanded to lay out a high quality page impose these requirements on such a system.

In most other text display applications where raster displays are used, each character in a font is represented as a matrix of binary values, representing white/black dots on the display. Such applications only require that the character font be legible. For this reason most text display systems provide only one character font, and this font is simple and tuned to the characteristics

Massachusetts Institute of Technology Page 1 Dec 31, 1980

Page 2 of 7

The Display of Characters Using Gray Level Sample Arrays

of the display. However, when applications arise that relate to the printing industry, then the standards regarding the printed word change dramatically. It is common, for instance, for a single advertisement to contain a dozen fonts having different sizes, weights, and styles. A technical article may contain as many as thirty different variations of fonts. In these applications the...