iTextSharp.text.pdf.codec.TiffImage.GetDpi C# (CSharp) 메소드

        static int GetDpi(TIFFField fd, int resolutionUnit)
        {
            if (fd == null)
                return 0;
            long[] res = fd.GetAsRational(0);
            float frac = (float)res[0] / (float)res[1];
            int dpi = 0;
            switch (resolutionUnit) {
                case TIFFConstants.RESUNIT_INCH:
                case TIFFConstants.RESUNIT_NONE:
                    dpi = (int)(frac + 0.5);
                    break;
                case TIFFConstants.RESUNIT_CENTIMETER:
                    dpi = (int)(frac * 2.54 + 0.5);
                    break;
            }
            return dpi;
        }