NAME
        ScalerDiv -- Get the scaling result that bitmapscale would. (v36)

   SYNOPSIS
        result = ScalerDiv(factor, numerator, denominator)
        D0                 D0      D1         D2

        uword scalerdiv(uword, uword, uword);

   FUNCTION
        Calculate the expression (factor*numerator/denominator) such
        that the result is the same as the width of the destination
        result of bitmapscale when the factor here is the width of
        the source, and the numerator and denominator are the
        XDestFactor and XSrcFactor for bitmapscale.

   INPUTS
        factor                 - a number in the range 0..16383
        numerator, denominator - numbers in the range 1..16383

   RESULT
        this returns factor*numerator/denominator