Workbook workbook = new Workbook();
workbook.LoadFromFile(input);
Worksheet sheet = workbook.Worksheets[0];
CellRange range = sheet.Range["A5:D20"];
sheet.Subtotal(range, 0, cols.ToArray(), SubtotalTypes.Sum, true, false, true);
workbook.SaveToFile(output,FileFormat.Version2013);

chart.Series[0].Format.Options.BubbleScale = x;

//1)Relative location
Workbook workbook = new Workbook();
Worksheet worksheet = workbook.Worksheets[0];
XlsLineShape line = worksheet.TypedLines.AddLine() as XlsLineShape;
line.LeftColumn = 10; //The column index of the starting point
line.LeftColumnOffset = 10; //The amount of column deviation from the starting point
line.TopRow = 10; //The row index of the starting point
line.TopRowOffset = 10; //The amount of row deviation from the starting point
line.RightColumn = 17; //The column index of the end point
line.RightColumnOffset = 10; //The amount of column deviation from the end point
line.BottomRow = 18; //The row index of the end point
line.BottomRowOffset = 10; //The amount of row deviation from the end point
workbook.SaveToFile("result.xlsx", ExcelVersion.Version2013);
workbook.Dispose();
//2)Absolute location in pixels
Workbook workbook1 = new Workbook();
Worksheet worksheet1 = workbook1.Worksheets[0];
XlsLineShape line1 = worksheet1.TypedLines.AddLine() as XlsLineShape;
line1.StartPoint = new Point(20, 30);
line1.EndPoint = new Point(20, 50);
workbook1.SaveToFile("result2.xlsx", ExcelVersion.Version2013);
workbook1.Dispose();

//Add digital signature
X509Certificate2 x509 = new X509Certificate2(inputPfx, "e-iceblue");
ppt.AddDigitalSignature(x509, "111", DateTime.Now);
//Remove digital signature
if (ppt.IsDigitallySigned == true) 
{ 
ppt.RemoveAllDigitalSignatures(); 

Presentation ppt = new Presentation();
ppt.LoadFromFile(inputFile);
IChart chart = ppt.Slides[0].Shapes[0] as IChart;
ITrendlines trendline = chart.Series[0].TrendLines[0] as ITrendlines;
trendline.displayEquation = false;
trendline.displayRSquaredValue = false;
trendline.Name = "trendlineName";
trendline.Line.FillType = FillFormatType.Solid;
trendline.Line.SolidFillColor.Color = Color.Red;
ppt.SaveToFile(outputFile, FileFormat.Pptx2010);
ppt.Dispose();

ppt.Slides[0].SlideShowTransition.Type = TransitionType.Morph;