The Bressenham Line Algorithm is found in almost every computer graphic text published in the last 30 years. “The algorithm may be programmed without multiplication or division instructions and is efficient with respect to speed of execution and memory utilization” [3]. The elegant simplicity is sometimes lost in our world of gigahertz processors and tetrabyte storage, but you will still find it being embedded in graphics processor chips.
The long dimension of the line is incremented as each pixel is drawn, and the fractional slope is accumulated in the error term. When the error term exceeds the threshold, the short dimension is incremented, and the error term is reset for the next iteration.