在C#中将PDF页面拆分为多页 [英] Split PDF page to multiple page in C#

问题描述

我正在使用C#为Windows 8.1创建一个应用程序.在Windows.Data.Pdf中，我发现了如何在应用程序中使用PDF文件.但是我想知道是否可以将一个A3页面拆分为多个PDF文件吗?

I'm creating an application for Windows 8.1 in C#. Into Windows.Data.Pdf i've found how use PDF files in my application. But i want to know if i can split one A3 page to multiple PDF files ?

推荐答案

您不想拆分页面，而是想要平铺页面.

You don't want to split a page, you want to tile it.

在我的书的第6章(第6.2.3节)中对此进行了说明.看一下TilingHero示例( Java / C#).在此示例中，一个大页面( hero.pdf )分为一个带有多个A4页的PDF( superman.pdf ).

This is explained in Chapter 6 of my book (section 6.2.3). Take a look at the TilingHero example (Java / C#). In this example, one large page (hero.pdf) is split into a PDF with several A4 pages (superman.pdf).

这是一些代码:

PdfReader reader = new PdfReader(resource);
Rectangle pagesize = reader.GetPageSizeWithRotation(1); 
using (Document document = new Document(pagesize)) {
    // step 2
    PdfWriter writer = PdfWriter.GetInstance(document, ms);
    // step 3
    document.Open();
    // step 4
    PdfContentByte content = writer.DirectContent;
    PdfImportedPage page = writer.GetImportedPage(reader, 1);
    // adding the same page 16 times with a different offset
    float x, y;
    for (int i = 0; i < 16; i++) {
        x = -pagesize.Width * (i % 4);
        y = pagesize.Height * (i / 4 - 3);
        content.AddTemplate(page, 4, 0, 0, 4, x, y);
        document.NewPage();
     }
}

该数学运算对于A0页面有效.您需要对其进行调整以适应A3页面(这意味着:您所需的数学运算更容易实现).

The math is valid for an A0 page. You need to adapt it for an A3 page (meaning: the math you need is way easier to do).

您需要计算pagesize以便它生成较小的页面，然后使用类似以下的内容:

You need to calculate pagesize so that it results in smaller pages, and then use something like this:

using (Document document = new Document(pagesize)) {
    // step 2
    PdfWriter writer = PdfWriter.GetInstance(document, ms);
    // step 3
    document.Open();
    // step 4
    PdfContentByte content = writer.DirectContent;
    PdfImportedPage page = writer.GetImportedPage(reader, 1);
    // adding the same page 16 times with a different offset
    float x, y;
    for (int i = 0; i < 16; i++) {
        x = -pagesize.Width * (i % 4);
        y = pagesize.Height * (i / 4 - 3);
        content.AddTemplate(page, x, y); // we don't scale anymore
        document.NewPage();
     }
}

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