Reading PDF content with itextsharp dll in VB.NET or C#
How can I read PDF content with the itextsharp with the Pdfreader class. My PDF may include Plain text or Images of the text.
using iTextSharp.text.pdf;
using iTextSharp.text.pdf.parser;
using System.IO;
public string ReadPdfFile(string fileName)
{
StringBuilder text = new StringBuilder();
if (File.Exists(fileName))
{
PdfReader pdfReader = new PdfReader(fileName);
for (int page = 1; page <= pdfReader.NumberOfPages; page++)
{
ITextExtractionStrategy strategy = new SimpleTextExtractionStrategy();
string currentText = PdfTextExtractor.GetTextFromPage(pdfReader, page, strategy);
currentText = Encoding.UTF8.GetString(ASCIIEncoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)));
text.Append(currentText);
}
pdfReader.Close();
}
return text.ToString();
}
You can't read and parse the contents of a PDF using iTextSharp like you'd like to.
From iTextSharp's SourceForge tutorial:
You can't 'parse' an existing PDF file using iText, you can only 'read' it page per page.
What does this mean?
The pdf format is just a canvas where text and graphics are placed without any structure information. As such there aren't any 'iText-objects' in a PDF file. In each page there will probably be a number of 'Strings', but you can't reconstruct a phrase or a paragraph using these strings. There are probably a number of lines drawn, but you can't retrieve a Table-object based on these lines. In short: parsing the content of a PDF-file is NOT POSSIBLE with iText. Post your question on the newsgroup news://comp.text.pdf and maybe you will get some answers from people that have built tools that can parse PDF and extract some of its contents, but don't expect tools that will perform a bullet-proof conversion to structured text.
LGPL / FOSS iTextSharp 4.x
var pdfReader = new PdfReader(path); //other filestream etc
byte[] pageContent = _pdfReader .GetPageContent(pageNum); //not zero based
byte[] utf8 = Encoding.Convert(Encoding.Default, Encoding.UTF8, pageContent);
string textFromPage = Encoding.UTF8.GetString(utf8);
None of the other answers were useful to me, they all seem to target the AGPL v5 of iTextSharp. I could never find any reference to SimpleTextExtractionStrategy or LocationTextExtractionStrategy in the FOSS version.
Something else that might be very useful in conjunction with this:
const string PdfTableFormat = @"(.*)Tj";
Regex PdfTableRegex = new Regex(PdfTableFormat, RegexOptions.Compiled);
List<string> ExtractPdfContent(string rawPdfContent)
{
var matches = PdfTableRegex.Matches(rawPdfContent);
var list = matches.Cast<Match>()
.Select(m => m.Value
.Substring(1) //remove leading (
.Remove(m.Value.Length - 4) //remove trailing )Tj
.Replace(@")", ")") //unencode parens
.Replace(@"(", "(")
.Trim()
)
.ToList();
return list;
}
This will extract the text only data from the PDF, if the text displayed is Foo(bar) it will be encoded in the PDF as (Foo(bar))Tj , this method would return Foo(bar) as expected. This method will strip out lots of additional information such as location coordinates from the raw pdf content.