Browse Prior Art Database

Reduction of Character Raster Pattern Resolution Without Stroke Width Variation

IP.com Disclosure Number: IPCOM000060519D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 48K

Publishing Venue

IBM

Related People

Czyszczewski, JS: AUTHOR [+4]

Abstract

A method is described to maintain the width of vertical lines in a character constant when the horizontal resolution of a character is changed electronically. This method relates to printers that print characters based on character raster patterns. More specifically, this method deals with the processing that is performed to reduce the horizontal resolution of the character raster patterns without significantly reducing the print quality of the modified characters. The term "stroke" is used to describe the imaginary brush stroke that is used to "paint" the lines that make up a character when the artwork for the character is created. The pel (print element) pattern for the character is based on this original artwork.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 44% of the total text.

Page 1 of 3

Reduction of Character Raster Pattern Resolution Without Stroke Width Variation

A method is described to maintain the width of vertical lines in a character constant when the horizontal resolution of a character is changed electronically. This method relates to printers that print characters based on character raster patterns. More specifically, this method deals with the processing that is performed to reduce the horizontal resolution of the character raster patterns without significantly reducing the print quality of the modified characters. The term "stroke" is used to describe the imaginary brush stroke that is used to "paint" the lines that make up a character when the artwork for the character is created. The pel (print element) pattern for the character is based on this original artwork. The term "character raster pattern" is used to describe the arrangement of print pels or ink dots that represent the shape of the character to be printed. The term "OR" is used to described the boolean logic "OR" function. Printers based on all-points addressable (APA) technologies use character raster patterns to print text. Each character is digitized from an artwork image of the character based on the horizontal and vertical pel resolution of the printer with which the raster patterns will be used. The resulting pel pattern is stored in a horizontal or vertical raster format in the printer or print server. Assume the printer directly supports text, graphics, and image data types by pluggable and resident font modules. The characters in the font modules are designed and are stored at a resolution of 240 vertical by 360 horizontal pels per inch to provide letter quality printing for text data. Assume also that the printer prints at two horizontal resolutions. Graphics data is printed at a resolution of 240 horizontal and vertical pels per inch which is lower than the text printing resolution. Also, characters are printed as part of the graphics data. However, the high resolution text characters cannot be directly used at the graphics resolution without modification because of this difference in horizontal print resolutions. Scaling in the horizontal direction is required to use the high resolution text character raster patterns in the graphics mode. A 3 to 2 reduction in the number of pels in the high resolution characters will allow them to be used at the graphics resolution. This is based on the graphics-mode pels being wider than the text-mode pels by a factor of 3 to 2. The real problem is that the width of the resulting vertical character strokes vary as a function of the horizontal position of the stroke in the character box. Instead of one-stroke width, the vertical lines are printed with two- stroke widths. This is most noticeable when vertical lines in the same character have different stroke widths. Unlike the raggedness, the stroke width variation is easily detected with an unaided eye. The new method is based on the realization...