itext将文本添加到pdf增加文件大小 [英] itext add text to pdf increase file size

问题描述

我有一个PDF文件，我想在每个页面上添加一个简单的数字。

I have a PDF file and I want to add a simple number on each page.

这是我的代码：

reader = new PdfReader(fileOut);
Document final = new Document(reader.GetPageSize(1));
PdfWriter w = PdfWriter.GetInstance(final, new FileStream(finalFile, FileMode.Create, FileAccess.Write));
w.SetFullCompression();

final.Open();

for (int i = 1; i <= reader.NumberOfPages; i++)
{
    final.NewPage();
    PdfContentByte cb = w.DirectContent;
    ControlNumberTimes(cb, "C"+i, 560, 725, 270, Element.ALIGN_LEFT);
    cb.AddTemplate(w.GetImportedPage(reader, i), 0, 0);
}

final.Close();
reader.Close();



private static void ControlNumberTimes( PdfContentByte cb1, string control, int x, int y, int rotation, int allign )
{
    cb1.BeginText();

    cb1.SetColorFill(BaseColor.BLACK);
    cb1.SetFontAndSize(BaseFont.CreateFont("C:\\windows\\Fonts\\times.ttf", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED), 7.5f);
    cb1.ShowTextAligned(allign, control, x, y, rotation);
    cb1.EndText();
}

在添加此文本之前，PDF文件大小为3.6 Mb，大小为11 Mb。
我做错了什么？

Before adding this text, PDF file size is 3.6 Mb, after the size is 11 Mb. What I am doing wrong?

这是我现在的代码：

string finalFile = System.IO.Path.GetDirectoryName(fileOut) + "\\" +
                           System.IO.Path.GetFileNameWithoutExtension(fileOut) + "_num.pdf";

        reader = new PdfReader(fileOut);

        using (FileStream fs = new FileStream(finalFile, FileMode.Create, FileAccess.Write, FileShare.None))
        {
            using (PdfStamper stamper = new PdfStamper(reader, fs))
            {
                int pageCount = reader.NumberOfPages;
                for (int i = 1; i <= pageCount; i++)
                {
                    ColumnText.ShowTextAligned(stamper.GetUnderContent(i), Element.ALIGN_CENTER, new Phrase(
                        $"C{i}"), 560, 725, 0);
                }
            }
        }

pdf文件我可以' t分享到机密信息。

The pdf file I can't share due of the confidential information.

推荐答案

这是完全错误的：

reader = new PdfReader(fileOut);
Document final = new Document(reader.GetPageSize(1));
PdfWriter w = PdfWriter.GetInstance(final, new FileStream(finalFile, FileMode.Create, FileAccess.Write));
w.SetFullCompression();
final.Open();
for (int i = 1; i <= reader.NumberOfPages; i++)
{
    final.NewPage();
    PdfContentByte cb = w.DirectContent;
    ControlNumberTimes(cb, "C"+i, 560, 725, 270, Element.ALIGN_LEFT);
    cb.AddTemplate(w.GetImportedPage(reader, i), 0, 0);
}
final.Close();

说我正在使用文件复制文件， PdfWriter ， PdfImportedPage 和 AddTemplate ，为什么我的文件大小增加？就像问我用锋利的刀刺伤自己的肚子，我为什么要流血？

Saying "I am copying a file using Document, PdfWriter, PdfImportedPage and AddTemplate, why does my file size increase?" is like asking "I've stabbed myself in the belly with a sharp knife, why do I bleed?"

如果你想在现有文件中添加页码，您必须按 PdfStamper 9b03-3f9aca1921a5 / samplechapter6.pdfrel =nofollow>我书中的第6章。

If you want to add page numbers to an existing document, you have to use PdfStamper as explained in chapter 6 of my book.

你想操纵现有PDF ，更具体地说，您希望在页脚中添加页码。这是这样做的：

You want to manipulate an existing PDF, more specifically, you want to add page numbers in the footer. That is done like this:

PdfReader reader = new PdfReader(outputFile);
using (FileStream fs = new FileStream(secondFile, FileMode.Create, FileAccess.Write, FileShare.None)) {
    using (PdfStamper stamper = new PdfStamper(reader, fs)) {
        int PageCount = reader.NumberOfPages;
        for (int i = 1; i <= PageCount; i++) {
            ColumnText.ShowTextAligned(stamper.GetOverContent(i), Element.ALIGN_CENTER, new Phrase(String.Format("Page {0} of {1}", i, PageCount)), 560, 725, 270);
        }
    }
}

一些评论：

• 您正在使用绝对坐标（X = 560，Y = 725）。如官方文档中所述，最好使用相对于页面大小的坐标：如何相对于页面定位文本？


• 您正在使用 BeginText（） ... EndText（），但是你可能更容易使用 ColumnText.ShowTextAligned（）。


• 你认为你使用的字体不是在您创建 BaseFont 时嵌入，如此 BaseFont.CreateFont（C：\\windows \\Fonts \\ times。 ttf，BaseFont.IDENTITY_H，BaseFont.NOT_EMBEDDED）。这不是真的。如上所述，使用 BaseFont.IDENTITY_H 时，将忽略 BaseFont.NOT_EMBEDDED 。请参阅为什么iText嵌入字体即使我指定不嵌入？如果需要小文件大小，我建议你不要嵌入字体。

• You are using absolute coordinates (X = 560, Y = 725). It would be better to use coordinates relative to the page size as described in the official documentation: How to position text relative to page?
• You are using BeginText() ... EndText(), but it might be easier for you to use ColumnText.ShowTextAligned().
• You think you are using a font that isn't embedded when you create a BaseFont like this BaseFont.CreateFont("C:\\windows\\Fonts\\times.ttf", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED). That's not true. As documented, BaseFont.NOT_EMBEDDED is ignored when using BaseFont.IDENTITY_H. See Why is iText embedding a font even when I specify not to embed? If a small file size is desired, I suggest you don't embed the font.

您的代码的主要问题是您没有以正确的方式操作文件。我认为这是因为您从一个写得不好的教程中复制/粘贴了您的代码。请不要复制那些不知道他们正在做什么的人的代码。

The main problem with your code, is the fact that you aren't manipulating a file the correct way. I think this is caused by the fact that you copy/pasted your code from a badly written tutorial. Please don't copy code from people who don't know what they're doing.

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