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Integer Arithmetic Algorithm for Anti-Aliased Line Drawing

IP.com Disclosure Number: IPCOM000062288D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09

Publishing Venue

IBM

Related People

Authors:
West, RM [+details]

Abstract

As the pel (picture element) densities of raster displays increase, simpler filtering techniques may be used to produce anti-aliased lines and edges. However, the number of pels, for which data must be obtained, will also increase. The requirement is for an algorithm to obtain the large quantity of grey-scale data at a high rate. The algorithm, described herein, incorporates the simple two-pel filtering of the "Slope of Intensity" technique into a procedure of computational simplicity similar to the "Bresenham" line-generating algorithm. The algorithm uses integer arithmetic. By eliminating the slope calculation, the arithmetic is restricted to addition, subtraction and bit- shifting, avoiding the computationally expensive use of division.