I can't flatten merged PDF with itextsharp - pdf

Question

I have 3 pdfs templates that i Fill out and save to a memorystream them merge them together into 1 pdf into a memorystream. The resulting merged pdf is non flattenned. I tried reading the merged pdf and flattening it but it say "pdf header signature not found". Is there a way to flattened merged pdf from a memorystream.
this is what I tried so far without success.
var mergedPdf = MergePDFs(AllPdfs);
MemoryStream flattenedMergedPdf = new MemoryStream();
PdfReader Finalpdf = new PdfReader(mergedPdf);
PdfStamper StampFinalMerged = new PdfStamper(Finalpdf,flattenedMergedPdf);
StampFinalMerged.FormFlattening=true;
return flattenedMergedPdf;
the method i use to merge the pdfs(found on SO) is below:
public MemoryStream MergePDFs(List<byte[]> pdfFiles)
{
if (pdfFiles.Count > 1)
{
PdfReader finalPdf;
Document pdfContainer;
PdfCopy pdfCopy;
MemoryStream msFinalPdf = new MemoryStream();
finalPdf = new PdfReader(pdfFiles[0]);
pdfContainer = new Document();
pdfCopy = new PdfSmartCopy(pdfContainer, msFinalPdf);
pdfContainer.Open();
for (int k = 0; k < pdfFiles.Count; k++)
{
finalPdf = new PdfReader(pdfFiles[k]);
for (int i = 1; i < finalPdf.NumberOfPages + 1; i++)
{
((PdfSmartCopy)pdfCopy).AddPage(pdfCopy.GetImportedPage(finalPdf, i));
}
pdfCopy.FreeReader(finalPdf);
}
//tried this here but no success
// PdfReader FinalRead = new PdfReader(finalPdf);
//MemoryStream FinalMS = new MemoryStream();
//var finalStamper = new PdfStamper(FinalRead, FinalMS);
//finalStamper.FormFlattening = true;
pdfCopy.CloseStream = false;
pdfCopy.Close();
finalPdf.Close();
//return FinalMS
return msFinalPdf;
}
Any help will be much appreciated. Thanks

Answer 1

You can try another approach to flatten PDF templates first then merge them into a final PDF file:
string newFile = "... path to the merged pdf file ...";
string[] pdfTemplates = new string[3];
string pdfTemplates[0] = "... path to the 1st pdf template ...";
string pdfTemplates[1] = "... path to the 2nd pdf template ...";
string pdfTemplates[2] = "... path to the 3rd pdf template ...";
string[] pdfFiles = new string[3];
string pdfFiles[0] = "... path to the 1st temp pdf file ...";
string pdfFiles[1] = "... path to the 2nd temp pdf file ...";
string pdfFiles[2] = "... path to the 3rd temp pdf file ...";
for (int i = 0; i < 3; i++)
{
PdfReader pdfReader = new PdfReader(pdfTemplates[i]);
PdfStamper pdfStamper = new PdfStamper(pdfReader, new FileStream(pdfFiles[i], FileMode.Create));
pdfStamper.FormFlattening = true;
pdfStamper.Close();
}
MergeFiles(newFile, pdfFiles);
for (int i = 0; i < 3; i++)
{
FileInfo fi = new FileInfo(pdfFiles[i]);
fi.Delete();
}
private void MergeFiles(string destinationFile, string[] sourceFiles)
{
try
{
int f = 0;
PdfReader reader = new PdfReader(sourceFiles[f]);
int n = reader.NumberOfPages;
Document document = new Document(reader.GetPageSizeWithRotation(1));
PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(destinationFile, FileMode.Create));
document.Open();
PdfContentByte cb = writer.DirectContent;
PdfImportedPage page;
int rotation;
while (f < sourceFiles.Length)
{
int i = 0;
while (i < n)
{
i++;
document.SetPageSize(reader.GetPageSizeWithRotation(i));
document.NewPage();
page = writer.GetImportedPage(reader, i);
rotation = reader.GetPageRotation(i);
if (rotation == 90 || rotation == 270)
{
cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(i).Height);
}
else
{
cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);
}
}
f++;
if (f < sourceFiles.Length)
{
reader = new PdfReader(sourceFiles[f]);
n = reader.NumberOfPages;
}
}
document.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}