result = ScalerDiv(factor, numerator, denominator)
D0 D0 D1 D2
UWORD ScalerDiv(UWORD, UWORD, UWORD);
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.