1. A method for rasterization, comprising the steps of: receiving a first set of coefficients representing a first functional and a bounding box offset; and using a computer device for computing a second set of coefficients a, b and c representing a second functional f(x, y)=a·x+b·y+c, the second functional falling within a quadrant indicated by a<0 and b≧0; wherein the computing step comprises scaling an intermediate value, the scaling comprising a cyclic bit-rotation of the intermediate value, whereby the intermediate value is represented within a first bit-length, a scaled version of the intermediate value is represented within a second bit-length, and the second bit-length does not exceed the first bit-length; based on the second functional, computing edge values and generating spans using the edge values; and rendering pixels based on the spans.