Splitting Big PDF Documents into Smaller Files Efficiently
Environment
| Version | Product | Author |
|---|---|---|
| 2025.1.205 | RadPdfProcessing | Desislava Yordanova |
Description
When working with large PDF documents, it might be necessary to split these documents into smaller "chunks" of a specified number of pages. This article shows a sample approach how to export efficiently subsets of pages without having to repeatedly re-import the entire document for each chunk.
Solution
To efficiently export subsets of pages from a large PDF document, the PdfStreamWriter functionality of RadPdfProcessing can be leveraged. This approach significantly improves performance and reduces memory usage, making it ideal for processing large volumes of PDFs. Below is a step-by-step guide on how to split a PDF document into smaller "chunks" using PdfStreamWriter.
Step 1: Include Necessary Namespaces
Ensure you include the necessary namespaces in your project:
using Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Streaming;
using Telerik.Windows.Documents.Fixed.Model;
Step 2: Implement the Splitting Logic
Use the following logic to split a PDF document into smaller chunks. This example splits a document into chunks of 10 pages each, but you can adjust the pagesCount variable to change the chunk size as needed.
internal class Program
{
public const string ResultDirName = @"..\..\..\Demo results";
public const string InputFileMultipageDocument = "YourLargePDF.pdf";
static void Main(string[] args)
{
EnsureEmptyResultDirectory();
SplitDocumentPages("YourLargePDF_Chunk[{0}-{1}].pdf");
}
private static void SplitDocumentPages(string resultFileFormat)
{
string documentToSplit = InputFileMultipageDocument;
int pagesCount = 10; // Number of pages per chunk
using (PdfFileSource fileToSplit = new PdfFileSource(File.OpenRead(documentToSplit)))
{
int totalPages = fileToSplit.Pages.Length;
int currentTotalPageIndex = 0;
int numberOfSplitDocs = totalPages / pagesCount + (totalPages % pagesCount == 0 ? 0 : 1);
for (int docIndex = 0; docIndex < numberOfSplitDocs; docIndex++)
{
int currentPagesEnd = Math.Min(currentTotalPageIndex + pagesCount, totalPages);
string splitDocumentName = Path.Combine(ResultDirName, string.Format(resultFileFormat, docIndex * pagesCount + 1, currentPagesEnd));
using (PdfStreamWriter fileWriter = new PdfStreamWriter(File.OpenWrite(splitDocumentName)))
{
for (int pageIndex = currentTotalPageIndex; pageIndex < currentPagesEnd; pageIndex++)
{
PdfPageSource page = fileToSplit.Pages[pageIndex];
fileWriter.WritePage(page);
currentTotalPageIndex++;
}
}
}
}
}
private static void EnsureEmptyResultDirectory()
{
if (Directory.Exists(ResultDirName))
{
foreach (string fileName in Directory.EnumerateFiles(ResultDirName))
{
File.Delete(fileName);
}
}
else
{
Directory.CreateDirectory(ResultDirName);
}
}
}
This solution efficiently processes the splitting operation by writing each chunk directly to a new file without the need to re-import the original document multiple times:
