18-01-2013, 02:40 PM
A Fast Bresenham Type Algorithm For Drawing Ellipses
A Fast Bresenham.PDF (Size: 172.33 KB / Downloads: 81)
Fast Ellipse Drawing
There is a well-known algorithm for plotting straight lines on a display device or a plotter where
the grid over which the line is drawn consists of discrete points or pixels. In working with a lattice of
points it is useful to avoid floating point arithmetic. One of the first published algorithms was by Jack
Bresenham who worked for I.B.M. ("*'&Ñ. The main idea in the algorithm is to analyze and manipulate
the linear equation so that only integer arithmetic is used in all the calculations. Integer arithmetic has
the advantages of speed and precision; working with floating point values requires more time and
memory and such values would need to be rounded to integers anyway. In this paper we consider the
more difficult problem of approximating the plot of an ellipse on a grid of discrete pixels, using only
integer arithmetic.
Before reading this paper it is suggested you read the paper by the same author on drawing circles.
The key ideas in the previous paper give all the details for circles, and there is much similarity between
drawing ellipses and circles. This paper will discuss the basic differences between circles and ellipses
but it assumes complete familiarity with the circle algorithm.