Fixed-point ellipse drawing alhorithm

This algorithm draws ellipses with integer centres and decimal radii on discrete devices using fixed-point arithmetic. These ellipses have both X and Y axis parallel to the coordinate axes. It uses forward differences to diminish its cost. It has a low comp utational complexity while the error is lower than traditional algorithms. This algorithm works in the squared R2 space (fixed-point) and translates directly the decimal points to the Z2 natural screen space