The DDA (Digital Differential Analyzer) algorithm is used to determine the interpolating points between any given two points linearly (i.e., a straight line). Now, as this needs to be done on a digital computer, speed is an important factor.
The equation of the line is given by the expression m = Δx / Δy eq (i), where Δx = x (2) -x (1) and Δy = y (2) -y (1),
now, using this equation, we could calculate the successive points lying on a line. But then this is the discrete world of raster graphics, so we need integral coordinates.
In simple DDA, eq (i) is converted to m = eΔx / eΔy, where e , let's call it the increment coefficient, is a positive real number. since placing the same number in the numerator and denominator does not change anything - but if it is selected accordingly - it can help us create discrete points, thereby reducing the overload of the need to round the resulting points.
: , , , , .
DDA-e 1/max (| Δx |, | Δy |), , . .. P (i + 1) = P (i) + (1, Round (e * Δy)), 1, e * Δy
DDA-e , , , , .
, e 1/2 ^ n, 2 ^ (n-1) <= max (| Δx |, | Δy |) < 2 ^ . , 2 ^ n. e * Δx e * Δy. : , , . , , .
http://w3.msi.vxu.se/~gsu/DAB726-Ht06/Symm-DDA.pdf .
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