Digital differential analyzer (graphics algorithm)

Digital Differential Analyzer (DDA)

DDA (digital differential analyzer) is used for generating pixels using a line formed by two points. It employees the equation for line representation (example: y=mx+c), then scan through an axis. Each scan it would determine the value on the other axis using the equation, this way the proper pixel can be located. Here is a sample C code of the DDA implementation:

Sample Code

{{citation}}: Empty citation (help) This is a sample DDA implementation in the C programming language:

void line DDA(int xa, int ya, int xb, int yb)
{
            int dx=xb-xa, dy=yb-ya, steps, k;
            float xIncrement, yIncrement, x=xa, y=ya;

            if(abs(dx)>abs(dy)) steps=abs(dx);
            else steps=abs(dy);        

            xIncrement=dx/(float)steps;
            yIncrement=dy/(float)steps;
            setPixel(ROUND(x), ROUND(y));
            for(k=0; k<steps; k++)
            {
                        x += xIncrement;
                        y += yIncrement;
                        setPixel(ROUND(x), ROUND(y));
            }
}

External links

• Basic Computer Graphics Programs