to_fixed_point
fixed_point fpSrcW = to_fixed_point(srcW);
fixed_point fpDestW = to_fixed_point(destW);
fixed_point fpSrcH = to_fixed_point(srcH);
fixed_point fpDestH = to_fixed_point(destH);
fixed_point column = to_fixed_point(i) * (long_fixed_point)fpSrcW
row = to_fixed_point(y) * (long_fixed_point)fpSrcH / fpDestH;
const int32 kFPOne = to_fixed_point(1);