The display of characters using gray level sample arrays

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.