Read roman page number of page - itext

Question

in Adobe Reader the first pages of a ebook can have roman format page number as shown in attached image below
Image : http://i.stack.imgur.com/GSm0Q.jpg
I would like to read these page numbers out (not the indexed page number) with iText but I don't know which properties (labels or annotations..) I should use. I could already open file with PdfReader, loop through all pages but have no idea what I should access for these roman numbers
using (Stream pdfStream = new FileStream(sourceFileName, FileMode.Open))
{
PdfReader pdfReader = new PdfReader(pdfStream);
for (int index = 1; index <= pdfReader.NumberOfPages; index++)
{
}
}
Thanks.

Answer 1

You are looking for the PageLabelExample. In this example, we have a PDF, page_labels.pdf that has pages numbered like this:
In the listPageLabels() method, we create a txt file with all the page labels:
public void listPageLabels(String src, String dest) throws IOException {
// no PDF, just a text file
PrintStream out = new PrintStream(new FileOutputStream(dest));
PdfReader reader = new PdfReader(src);
String[] labels = PdfPageLabels.getPageLabels(reader);
for (int i = 0; i < labels.length; i++) {
out.println(labels[i]);
}
out.flush();
out.close();
reader.close();
}
The result looks like this:
A
B
1
2
3
Movies-4
Movies-5
Movies-6
Movies-7
Movies-8
If you want an iTextSharp example, take a look at this method:
/**
* Reads the page labels from an existing PDF
* #param src the existing PDF
*/
public string ListPageLabels(byte[] src) {
StringBuilder sb = new StringBuilder();
String[] labels = PdfPageLabels.GetPageLabels(new PdfReader(src));
for (int i = 0; i < labels.Length; i++) {
sb.Append(labels[i]);
sb.AppendLine();
}
return sb.ToString();
}
Update
As promised in the comment section: PdfPageLabels.cs
I am not a C# developer, but this is a quick and dirty version of the GetPageLabels() method that doesn't add a prefix:
public static String[] GetPageLabels(PdfReader reader) {
int n = reader.NumberOfPages;
PdfDictionary dict = reader.Catalog;
PdfDictionary labels = (PdfDictionary)PdfReader.GetPdfObjectRelease(dict.Get(PdfName.PAGELABELS));
if (labels == null)
return null;
String[] labelstrings = new String[n];
Dictionary<int, PdfObject> numberTree = PdfNumberTree.ReadTree(labels);
int pagecount = 1;
char type = 'D';
for (int i = 0; i < n; i++) {
if (numberTree.ContainsKey(i)) {
PdfDictionary d = (PdfDictionary)PdfReader.GetPdfObjectRelease(numberTree[i]);
if (d.Contains(PdfName.ST)) {
pagecount = ((PdfNumber)d.Get(PdfName.ST)).IntValue;
}
else {
pagecount = 1;
}
if (d.Contains(PdfName.S)) {
type = ((PdfName)d.Get(PdfName.S)).ToString()[1];
}
else {
type = 'e';
}
}
switch (type) {
default:
labelstrings[i] = "" + pagecount;
break;
case 'R':
labelstrings[i] = RomanNumberFactory.GetUpperCaseString(pagecount);
break;
case 'r':
labelstrings[i] = RomanNumberFactory.GetLowerCaseString(pagecount);
break;
case 'A':
labelstrings[i] = RomanAlphabetFactory.GetUpperCaseString(pagecount);
break;
case 'a':
labelstrings[i] = RomanAlphabetFactory.GetLowerCaseString(pagecount);
break;
case 'e':
labelstrings[i] = "";
break;
}
pagecount++;
}
return labelstrings;
}