﻿

# Digital differential analyzer (graphics algorithm)

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 rasterization of lines, triangles and polygons. In its simplest implementation the DDA algorithm interpolates values in interval [(xstart, ystart), (xend, yend)] by computing for each xi the equations xi = xi−1+1/m, yi = yi−1 + m, where Δx = xend − xstart and Δy = yend − ystart and m = Δy/Δx

## Performance

The DDA method can be implemented using floating-point or integer arithmetic. The native floating-point implementation requires one addition and one rounding operation per interpolated value (e.g. coordinate x, y, depth, color component etc.) and output result. This process is only efficient when an FPU with fast add and rounding operation is available.

The fixed-point integer operation requires two additions per output cycle, and in case of fractional part overflow, one additional increment and subtraction. The probability of fractional part overflows is proportional to the ratio m of the interpolated start/end values.

DDAs are well suited for hardware implementation and can be pipelined for maximized throughput.

where m represents the slope the line and c is the y intercept . this slope can be expressed in DDA as

```      yend-ystart
m= -----------
xend-xstart
```

in fact any two consecutive point(x,y) laying on this line segment should satisfy the equation.

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• Digital Differential Analyzer (graphics algorithm) — In Computer graphics, an hard 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 rasterization of lines, triangles and… …   Wikipedia

• Digital differential analyzer — This article is about the digital implementation of a Differential Analyzer. For other uses of DDA, see DDA. For the graphics algorithm, see Digital Differential Analyzer (graphics algorithm). A digital differential analyzer (DDA), also sometimes …   Wikipedia

• Bresenham's line algorithm — The Bresenham line algorithm is an algorithm that determines which points in an n dimensional raster should be plotted in order to form a close approximation to a straight line between two given points. It is commonly used to draw lines on a… …   Wikipedia

• List of acronyms and initialisms: D — This list contains acronyms, initialisms, and pseudo blends that begin with the letter D. For the purposes of this list: acronym = an abbreviation pronounced as a series of constituent letters, e.g., SARS = severe acute respiratory syndrome… …   Wikipedia

• Rasterung von Linien — Die Rasterung von Linien ist eine elementare Aufgabe der Computergrafik, bei der eine Linie auf das Punktraster einer Rastergrafik oder eines Raster Grafikgeräts gezeichnet (gerastert) wird. Dazu werden diejenigen Punkte oder Pixel eingefärbt,… …   Deutsch Wikipedia

• computer — computerlike, adj. /keuhm pyooh teuhr/, n. 1. Also called processor. an electronic device designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations. Cf. analog… …   Universalium

• List of file formats — This is an incomplete list, which may never be able to satisfy particular standards for completeness. You can help by expanding it with reliably sourced entries. See also: List of file formats (alphabetical) This is a list of file formats… …   Wikipedia