PdfDocument pdf = new PdfDocument();
 PdfPageBase page = pdf.Pages.Add();
 PdfRGBColor c = Color.Purple;

 //color space RGB
 PdfSeparationColorSpace cs = new PdfSeparationColorSpace("MySpotColor", new PdfRGBColor(c.R, c.G, c.B));
 //color space CMYK
 PdfSeparationColorSpace cs = new PdfSeparationColorSpace("MySpotColor", new PdfRGBColor(c.C, c.M, c.Y, c.K));
 //color space Grayscale
 PdfSeparationColorSpace cs = new PdfSeparationColorSpace("MySpotColor", new PdfRGBColor(c.Gray));

 PdfSeparationColor color = new PdfSeparationColor(cs, 1f);
 PdfSolidBrush brush = new PdfSolidBrush(color);
 page.Canvas.DrawPie(brush, 10, 30, 60, 60, 360, 360);
 page.Canvas.DrawString("Tint=1.0", new PdfFont(PdfFontFamily.Helvetica, 10f), brush, new PointF(22, 100));
 color = new PdfSeparationColor(cs, 0.5f);
 brush = new PdfSolidBrush(color);
 page.Canvas.DrawPie(brush, 80, 30, 60, 60, 360, 360);
 page.Canvas.DrawString("Tint=0.5", new PdfFont(PdfFontFamily.Helvetica, 10f), brush, new PointF(92, 100));
 color = new PdfSeparationColor(cs, 0.25f);
 brush = new PdfSolidBrush(color);
 page.Canvas.DrawPie(brush, 150, 30, 60, 60, 360, 360);
 page.Canvas.DrawString("Tint=0.25", new PdfFont(PdfFontFamily.Helvetica, 10f), brush, new PointF(162, 100));
 pdf.SaveToFile("SpotColorrgb.pdf");

PdfCompressor compressor = new PdfCompressor(fileName);
compressor.Options.TextCompressionOptions.UnembedFonts = true;
compressor.CompressToFIle(outputName);

RectangleF rect = new RectangleF(x, y, 100, 15);
PdfFreeTextAnnotation textAnnotation = new PdfFreeTextAnnotation(rect);
TextAlignment(textAnnotation);
textAnnotation.TextAlignment = PdfAnnotationTextAlignment.Right;

using (FileStream fileStream = new FileStream(outputFile, FileMode.Create))
{
    PdfCompressor compressor = new PdfCompressor(inputFile);
    compressor.CompressToStream(fileStream);
    fileStream.Flush();
    fileStream.Close();
}

Workbook workbook = new Workbook();
workbook.LoadFromFile(@"ToCSV.xlsx");
Worksheet sheet = workbook.Worksheets[0];
//The last parameter " true" makes the result strings have quotation marks
sheet.SaveToFile(@"ToCSV.csv", ",",true);

Workbook book = new Workbook();
book.LoadFromFile(inputFile);
Worksheet sheet = book.Worksheets[0];
CellRange targetCell = sheet.Range["E2"];
CellRange gussCell = sheet.Range["B4"];
GoalSeek goalSeek = new GoalSeek();
GoalSeekResult result= goalSeek.TryCalculate (targetCell, 2000, gussCell);
result.Determine();

Workbook workbook = new Workbook();
workbook.Worksheets[0].Range["A1"].Formula = "FLOOR.MATH(12.758,2,-1)";
workbook.CalculateAllValue();
workbook.SaveToFile("result.xlsx");