iTextSharp PDF一次性合并和添加页码 [英] iTextSharp PDF Merging and adding page number in one go

问题描述

我使用以下代码合并页面编号并将其添加到文档中:

I use this code to merge and add page number to the document:

            Using stream As FileStream = New FileStream(targetPDF, FileMode.Create)
            Dim myDoc As Document
            If (ExportOption.Orientation = Global.GenerateReport.GenerateReport.Orientation.Portrait) Then
                myDoc = New Document(New iTextSharp.text.Rectangle(PAGE_WIDTH, PAGE_HEIGHT), MARGIN_LEFT, MARGIN_RIGHT, MARGIN_TOP, MARGIN_BOTTOM)
                myDoc.SetPageSize(PageSize.A4)
            Else
                myDoc = New Document(New iTextSharp.text.Rectangle(PAGE_WIDTH, PAGE_HEIGHT), MARGIN_LEFT, MARGIN_RIGHT, MARGIN_TOP, MARGIN_BOTTOM)
                myDoc.SetPageSize(PageSize.A4.Rotate())
            End If
            Dim pdfCopy As PdfCopy = New PdfCopy(myDoc, stream)
            myDoc.Open()

            Dim files() As String = Directory.GetFiles(sourceDir)
            For Each pdffile As String In files
                Dim reader As PdfReader = New PdfReader(pdffile)
                pdfCopy.AddDocument(reader)
                reader.Close()
            Next

            If (Not myDoc Is Nothing) Then
                myDoc.Close()
                pdfCopy.Close()
            End If
        End Using

        Dim bytes As Byte() = File.ReadAllBytes(targetPDF)
        Dim blackFont As iTextSharp.text.Font = FontFactory.GetFont("HELVETICA", 8, iTextSharp.text.Font.NORMAL, BaseColor.BLACK)
        Using stream As New MemoryStream()
            Dim reader As New PdfReader(bytes)
            Using stamper As New PdfStamper(reader, stream)

                Dim bottom As Single = 10.0F
                Dim left As Single = 550.0F

                Dim pages As Integer = reader.NumberOfPages
                For i As Integer = 1 To pages
                    ColumnText.ShowTextAligned(stamper.GetUnderContent(i), Element.ALIGN_RIGHT, New Phrase("Page " & i.ToString() & " of " & reader.NumberOfPages, blackFont), left, bottom, 0)
                Next
            End Using
            bytes = stream.ToArray()
        End Using
        File.WriteAllBytes(targetPDF, bytes)

我怎么能一口气做到呢?

How can I do it in just one go?

有关我的情况的更多详细信息:我需要创建一个大文件，正常情况下，代码运行了几天，并抛出了内存不足异常，因此我将其拆分为较小的文档，效果很好，但是页码是都错了，那么我来介绍这一部分.

Some more details about my situation: I need to create a big file, in normal way the code ran for several days and threw Out of memory exception, so I split it to smaller documents, it works great but the page number is all wrong, then I come to this part.

推荐答案

要合并文档并同时在文档上标记戳记，可以使用PdfCopy.PageStamp.样本 ConcatenateStamp.cs (对应于Java示例 ConcatenateStamp.java 本书"iText in Action-2nd Edition"中的内容)演示了PdfCopy.PageStamp的使用:

To merge documents and stamp something on them at the same time, you can use a PdfCopy.PageStamp. The sample ConcatenateStamp.cs (corresponding to the java sample ConcatenateStamp.java from the book "iText in Action - 2nd Edition") demonstrates the use of a PdfCopy.PageStamp:

using (Document document = new Document()) {
    using (PdfCopy copy = new PdfCopy(document, OUTPUT_STREAM)) {
        document.Open();
        // reader for document 1
        PdfReader reader1 = new PdfReader(r1);
        int n1 = reader1.NumberOfPages;
        // reader for document 2
        PdfReader reader2 = new PdfReader(r2);
        int n2 = reader2.NumberOfPages;
        // initializations
        PdfImportedPage page;
        PdfCopy.PageStamp stamp;
        // Loop over the pages of document 1
        for (int i = 0; i < n1; ) {
            page = copy.GetImportedPage(reader1, ++i);
            stamp = copy.CreatePageStamp(page);
            // add page numbers
            ColumnText.ShowTextAligned(
              stamp.GetUnderContent(), Element.ALIGN_CENTER,
              new Phrase(string.Format("page {0} of {1}", i, n1 + n2)),
              297.5f, 28, 0
            );
            stamp.AlterContents();
            copy.AddPage(page);
        }

        // Loop over the pages of document 2
        for (int i = 0; i < n2; ) {
            page = copy.GetImportedPage(reader2, ++i);
            stamp = copy.CreatePageStamp(page);
            // add page numbers
            ColumnText.ShowTextAligned(
              stamp.GetUnderContent(), Element.ALIGN_CENTER,
              new Phrase(string.Format("page {0} of {1}", n1 + i, n1 + n2)),
              297.5f, 28, 0
            );
            stamp.AlterContents();
            copy.AddPage(page);
        }   
    }   
}

(该示例使用C#而不是VB，但应该可以提供一个想法...)

(The sample is in C#, not VB but it should serve to give an idea...)

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