# The Basic Incremental Algorithm for line

Simple incremental algorithm is well-known also look
like DDA (Digital Differential Analyzer) algorithm. The pricnip of this
algorithm is based on periodical increase dx for co-ordinate x and also
dy for co-ordinate y. Start point is one from end point a line. Because
we pattern in raster, increase on directional axis will be (providing,
if line be inclined to axis x is directional axis x) right one dot.

Applet Increase for value x and y.

Method is following. In one loop we shall step by
step add to co-ordinate on a main axis value 1 and to co-ordinate on incident
axis add increase. If axis *x* is main, value slope equal *m.*If
axis y then value slope equal *1/m*. Real number co-ordinates of the
displayed objects must be rounded off. DDA algorithm used to calculations
new co-ordinate values before dot.

Applet Dwawing a line from left top dot. Please select second end dot. Key 1,2 for zooming.

### The Basic Incremental Algorithm [4].