PDF文件是否包含iref流? [英] Does PDF file contain iref stream?

问题描述

我仍在处理从PDF文件中读取数据的问题.
我使用PDFsharp，如何在不使用打开方法的情况下检查文件是否包含iref流.如果文件包含 iref流，则Open方法将引发异常.

I still fight with read data from PDF file.
I use PDFsharp, how can I check if file contains iref stream without use method Open. Method Open throws exception if file contains iref stream.

推荐答案

有一个已知的解决方法，也可以让您打开包含iref的pdf文件:您可以找到

There is a know workaround to permit you to open ALSO the pdf files that contains iref: you can find here the complete thread about that.

仅概述解决方案:

1. 下载并包含 iTextSharp 4.1.6库
2. 在代码文件中粘贴以下代码到您的项目中:

-

using System;
using System.IO;

namespace PdfSharp.Pdf.IO
{
    static public class CompatiblePdfReader
    {
        /// <summary>
        /// uses itextsharp 4.1.6 to convert any pdf to 1.4 compatible pdf, called instead of PdfReader.open
        /// </summary>
        static public PdfDocument Open(string pdfPath)
        {
            using (var fileStream = new FileStream(pdfPath, FileMode.Open, FileAccess.Read))
            {
                var len = (int)fileStream.Length;
                var fileArray = new Byte[len];
                fileStream.Read(fileArray, 0, len);
                fileStream.Close();

                return Open(fileArray);
            }
        }

        /// <summary>
        /// uses itextsharp 4.1.6 to convert any pdf to 1.4 compatible pdf, called instead of PdfReader.open
        /// </summary>
        static public PdfDocument Open(byte[] fileArray)
        {
            return Open(new MemoryStream(fileArray));
        }

        /// <summary>
        /// uses itextsharp 4.1.6 to convert any pdf to 1.4 compatible pdf, called instead of PdfReader.open
        /// </summary>
        static public PdfDocument Open(MemoryStream sourceStream)
        {
            PdfDocument outDoc;
            sourceStream.Position = 0;

            try
            {
                outDoc = PdfReader.Open(sourceStream, PdfDocumentOpenMode.Import);
            }
            catch (PdfReaderException)
            {
                //workaround if pdfsharp doesn't support this pdf
                sourceStream.Position = 0;
                var outputStream = new MemoryStream();
                var reader = new iTextSharp.text.pdf.PdfReader(sourceStream);
                var pdfStamper = new iTextSharp.text.pdf.PdfStamper(reader, outputStream) {FormFlattening = true};
                pdfStamper.Writer.SetPdfVersion(iTextSharp.text.pdf.PdfWriter.PDF_VERSION_1_4);
                pdfStamper.Writer.CloseStream = false;
                pdfStamper.Close();

                outDoc = PdfReader.Open(outputStream, PdfDocumentOpenMode.Import);
            }

            return outDoc;
        }
    }
}

1. 将所有呼叫从PdfReader.Open更改为CompatiblePdfReader.Open.

1. Change all your calls to PdfReader.Open to CompatiblePdfReader.Open.

对我来说，它像一种魅力，希望对您有帮助.

It works like a charm for me, hope this helps you.

这篇关于PDF文件是否包含iref流?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！