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Enlargement of Character Raster Patterns Without Character Corner Rounding

IP.com Disclosure Number: IPCOM000060483D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 49K

Publishing Venue

IBM

Related People

Czyszczewski, JS: AUTHOR [+2]

Abstract

A method is described in which the inside corners of a character remain sharp when the character raster pattern is enlarged and the ragged edges are made smooth. More specifically, this method deals with the preprocessing that is performed to enlarge characters without a significant reduction in print quality on printers that can scale a fixed-size character raster pattern. The term "character raster pattern" is used to describe the arrangement of pels (picture elements) or ink dots that represent the shape of a character to be printed. The word "corner" is used in two ways. A character corner is a point where the lines or arcs that describe the outline of the original artwork character meet at different angles.

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Enlargement of Character Raster Patterns Without Character Corner Rounding

A method is described in which the inside corners of a character remain sharp when the character raster pattern is enlarged and the ragged edges are made smooth. More specifically, this method deals with the preprocessing that is performed to enlarge characters without a significant reduction in print quality on printers that can scale a fixed-size character raster pattern. The term "character raster pattern" is used to describe the arrangement of pels (picture elements) or ink dots that represent the shape of a character to be printed. The word "corner" is used in two ways. A character corner is a point where the lines or arcs that describe the outline of the original artwork character meet at different angles. A corner in the rasterization pattern is a corner as defined above, but is based on the outline of the raster pattern character rather than the original artwork character. There are two types of corners in the character raster pattern. One type of corner represents a character corner and is referred to as a character corner. Fig. 2 shows an example of a character corner. The other type of corner results from the raggedness that is introduced when the artwork for a character is digitized. This type of corner is referred to as a rasterization corner. Fig. 3 shows an example of a rasterization corner. Corners are also identified as inside or outside corners. Inside corners are defined in Fig. 2. Most printers are being developed with all-points-addressable technologies and are based on the use of character raster patterns to print text. Each character is digitized based on the horizontal and vertical pel resolution of the printer, and the resulting pel pattern is stored in a horizontal or vertical raster format in the printer or print server. A significant feature of new printers is the ability to print fully composed pages which include text, image and vector graphics data types. In addition to handling all of the data types required to completely print a final form page, the new printers are required to handle a wide variety of character sizes in the text and vector graphics data types. In the past, printers only supported character width (pitch) selection. Now, it is important to support a wide range of character heights (point sizes). Large characters are required for headings, and small characters are required to print precise superscripts and subscripts for equations. The problem with providing characters in a wide variety of heights and widths is that a very large amount of storage is required to store the digitized character patterns. The ideal case is to store each character for a particular style in only one size and to use algorithms to generate character raster patterns in the required combination of character height and width when the font is selected. This technique greatly reduces the font storage requirements. However, the problem with...