本文介绍了iTextSharp添加现有页面的新实例的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
假设我有一个三页PDF,其中三个都有AcroFields。我需要能够生成一个新的PDF,第2页重复N次。第2页的每个新实例都需要修改字段名称,以使它们与第2页的其他实例不同。在此之前解决此问题的人是否可以提供语法示例?
Let's say I have a three page PDF and all three of them have AcroFields. I need to be able to generate a new PDF with page 2 repeated N number of times. Each new instance of page 2 will need to have the field names modified to make them distinct from the other instances of page 2. Can someone who's solved this problem before provide a syntax example?
推荐答案
这样可以生成一个大文件。我想这是因为第2页上的图像重复多次而不是重复使用。
This works but generates a large file. I guess it is because the image on page 2 is duplicated many times instead of being reused.
public static void ExpandRepeatingPages(string sourcePdfPath, string outputPdfPath)
{
/* figure out how many pages we are working with */
var transientPdfReader = new PdfReader(sourcePdfPath);
var numberOfPages = transientPdfReader.NumberOfPages;
transientPdfReader.Close();
var outputFileStream = new FileStream(outputPdfPath, FileMode.Create);
var pdfCopyFields = new PdfCopyFields(outputFileStream);
foreach (var pageNumber in Enumerable.Range(1, numberOfPages))
{
var pdfBytes = ExtractPageToBytes(sourcePdfPath, pageNumber);
var pdfReader = new PdfReader(pdfBytes);
pdfCopyFields.AddDocument(pdfReader);
pdfReader.Close();
if (pageNumber == 2)
{
foreach (var extraPageNumber in Enumerable.Range(2, 200))
{
var extraPagePdfBytes = RenamePageFields(pdfBytes, extraPageNumber);
pdfReader = new PdfReader(extraPagePdfBytes);
pdfCopyFields.AddDocument(pdfReader);
pdfReader.Close();
}
}
}
pdfCopyFields.Close();
}
public static byte[] ExtractPageToBytes(string sourcePdfPath, int pageNumber)
{
using (var memoryStream = new MemoryStream())
{
var pageNumbers = new System.Collections.ArrayList { pageNumber };
var pdfReader = new PdfReader(sourcePdfPath);
var pdfCopyFields = new PdfCopyFields(memoryStream);
pdfReader.SelectPages(pageNumbers);
pdfCopyFields.AddDocument(pdfReader);
pdfReader.RemoveUnusedObjects();
pdfCopyFields.Close();
pdfReader.Close();
return memoryStream.ToArray();
}
}
private static byte[] RenamePageFields(byte[] pdfBytes, int pageNumber)
{
using (var memoryStream = new MemoryStream())
{
var pdfReader = new PdfReader(pdfBytes);
var pdfStamper = new PdfStamper(pdfReader, memoryStream);
var acroFields = pdfStamper.AcroFields;
var fieldNames = acroFields.Fields.Keys.Cast<String>().ToList();
foreach (var fieldName in fieldNames)
{
var newName = String.Format("{0}_{1}", fieldName, pageNumber);
acroFields.RenameField(fieldName, newName);
}
pdfStamper.Close();
pdfReader.Close();
return memoryStream.ToArray();
}
}
这篇关于iTextSharp添加现有页面的新实例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!