Patent ID: 6915317

Claim:
A computer implemented method of converting a linear value to an integer for use in raster graphics comprising the steps of: inputting a coordinate value X: calculating the y coordinate value Z of point P having an x coordinate value X in accordance with a core calculation function: f(X, Y); said point P out of the points (hereinafter referred to as “integral lattice point”) where each coordinate value is an integer being located in the vicinity of side OA of a triangle OAB consisting of the origin O ( 0 , 0 ), point A (L, Y), point B (L, 0 ): Z=f ( X, Y ) wherein 0≦X≦L, 0≦Y≦L, X, Y: integers L=2 s −1, S≧1, S: an integer f(X, Y) satisfies all the conditions below, i) f( 0 , 0 )=0, and f(L, Y)=Y for arbitrary Y ii) for arbitrary 0≦X<L and arbitrary Y f ( X+ 1 , Y )= f ( X, Y )+0 or f ( X +1 , Y )= f ( X, Y )+1 iii) for arbitrary 0≦Y<L and arbitrary X f ( X, Y+ 1)= f ( X, Y )+0 or f ( X, Y+ 1)= f ( X, Y )+1 iv) an output Z is obtained without exception after a constant numbers of operating steps for arbitrary inputs X and Y; and outputting the converted coordinate value Z of point P to a raster graphics device.