Improving PDFs with Incremental Updates in C# and .NET
SautinSoft.Pdf allows users to modify PDF documents. Users do not have to wait for the entire file (which may contain hundreds of pages or more) to be rewritten each time changes to the document are saved.
The PDF format allows changes to be made to a file while leaving the original data intact. The appendices added when the file is incrementally updated will only contain the objects that were actually added or changed.
Since the original content of the document remains in the file, it is possible to undo saved changes by deleting one or more addenda. The ability to recover the exact contents of an original document is critical when digitally signing a PDF file with multiple signatures.
For more information about PDF incremental update in SautinSoft.Pdf, see File Structure help page.
The following example shows how to load a PDF document, add pages containing text, and save the changes using the incremental update feature.
Полный код
GitHubusing System;
using System.IO;
using SautinSoft;
using SautinSoft.Pdf;
using SautinSoft.Pdf.Content;
namespace Sample
{
class Sample
{
/// <summary>
/// Edit PDF files using incremental updates.
/// </summary>
/// <remarks>
/// Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/incremental-update.php
/// </remarks>
static void Main(string[] args)
{
// Before starting this example, please get a free 100-day trial key:
// https://sautinsoft.com/start-for-free/
// Apply the key here:
// PdfDocument.SetLicense("...");
string pdfFile = Path.GetFullPath(@"..\..\..\simple text.pdf");
// Load a PDF document from a file.
using (var document = PdfDocument.Load(pdfFile))
{
// Add a page.
var page = document.Pages.Add();
// Write a text.
using (var formattedText = new PdfFormattedText())
{
formattedText.Append("Hello World again!");
page.Content.DrawText(formattedText, new PdfPoint(100, 700));
}
// Save all the changes made to the current PDF document using an incremental update.
document.Save();
}
}
}
}
Option Infer On
Imports System
Imports System.IO
Imports SautinSoft
Imports SautinSoft.Pdf
Imports SautinSoft.Pdf.Content
Namespace Sample
Friend Class Sample
''' <summary>
''' Edit PDF files using incremental updates.
''' </summary>
''' <remarks>
''' Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/incremental-update.php
''' </remarks>
Shared Sub Main(ByVal args() As String)
' Before starting this example, please get a free 100-day trial key:
' https://sautinsoft.com/start-for-free/
' Apply the key here:
' PdfDocument.SetLicense("...");
Dim pdfFile As String = Path.GetFullPath("..\..\..\simple text.pdf")
' Load a PDF document from a file.
Using document = PdfDocument.Load(pdfFile)
' Add a page.
Dim page = document.Pages.Add()
' Write a text.
Using formattedText = New PdfFormattedText()
formattedText.Append("Hello World again!")
page.Content.DrawText(formattedText, New PdfPoint(100, 700))
End Using
' Save all the changes made to the current PDF document using an incremental update.
document.Save()
System.Diagnostics.Process.Start(New System.Diagnostics.ProcessStartInfo(pdfFile) With {.UseShellExecute = True})
End Using
End Sub
End Class
End Namespace
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