Gray-conversion is a time-consuming operation for drawing anti-aliased straight lines or curves. In order to improve the efficiency of drawing anti-aliased straight lines

we propose a new anti-aliasing algorithm based on a two-pixel model. Different from other anti-aliasing algorithms

a technique which controls iterations by grey values directly rather than distances is proposed. Calculations about distances between pixels and real line and distance-grey conversion are abandoned

but accurate grey values rather than estimated ones can be obtained. The analyses prove that for one step only 4～5 integer operations are invoked in this algorithm

and the drawing speed is faster than other methods. Furthermore

this algorithm can be constructed with the simplicity similar to basic scan conversion algorithms.