{{About|a graphics algorithm|the digital implementation of a Differential Analyzer|Digital Differential Analyzer}}
In [[computer graphics]], a hardware or software implementation of a '''[[digital differential analyzer]]''' ('''DDA)''') is used for linear interpolation of variables over an interval between start and end point. DDAs are used for [[Rasterisation|rasterization]] of lines, triangles and polygons. In its simplest implementation the DDA algorithm interpolates values in interval [(x<sub>start</sub>, y<sub>start</sub>), (x<sub>end</sub>, y<sub>end</sub>)] by computing for each x<sub>i</sub> the equations x<sub>i</sub> = x<sub>i−1</sub>+1/m, y<sub>i</sub> = y<sub>i−1</sub> + m, where Δx = x<sub>end</sub> − x<sub>start</sub> and Δy = y<sub>end</sub> − y<sub>start</sub> and m = Δy/Δx
