A Comparison Between iTextSharp and IronPDF For Editing PDFs

Prerequisites

Before we start, you will need the following:

1. Visual Studio installed on your machine.
2. Basic knowledge of the C# programming language.
3. iTextSharp library installed in your project.

To install the iTextSharp library in your project, you can use the NuGet package manager. Open your Visual Studio project and right-click on the project name in the Solution Explorer. Select "Manage NuGet Packages" from the context menu. In the NuGet Package Manager, search for "iTextSharp" and install the latest version of the package.

Creating a New PDF File

To create a new PDF file using iTextSharp, we need to create a new instance of the "Document" class and pass a new FileStream object to its constructor. Here's an example:

using iText.Kernel.Pdf;
using iText.Layout;
using iText.Layout.Element;
using iText.Layout.Properties;
using System.IO;

// Create a new PDF document
using (var writer = new PdfWriter(new FileStream("newfile.pdf", FileMode.Create)))
{
    using (var pdf = new PdfDocument(writer))
    {
        var document = new Document(pdf);

        // Create a header paragraph
        Paragraph header = new Paragraph("HEADER")
            .SetTextAlignment(TextAlignment.CENTER)
            .SetFontSize(16);

        // Add the header to the document
        document.Add(header);

        // Loop through pages and align header text
        for (int i = 1; i <= pdf.GetNumberOfPages(); i++)
        {
            Rectangle pageSize = pdf.GetPage(i).GetPageSize();
            float x = pageSize.GetWidth() / 2;
            float y = pageSize.GetTop() - 20;

            // Add the header text to each page
            document.ShowTextAligned(header, x, y, i, TextAlignment.LEFT, VerticalAlignment.BOTTOM, 0);
        }

        // Set the margins
        document.SetTopMargin(50);
        document.SetBottomMargin(50);
    }
}

using iText.Kernel.Pdf;
using iText.Layout;
using iText.Layout.Element;
using iText.Layout.Properties;
using System.IO;

// Create a new PDF document
using (var writer = new PdfWriter(new FileStream("newfile.pdf", FileMode.Create)))
{
    using (var pdf = new PdfDocument(writer))
    {
        var document = new Document(pdf);

        // Create a header paragraph
        Paragraph header = new Paragraph("HEADER")
            .SetTextAlignment(TextAlignment.CENTER)
            .SetFontSize(16);

        // Add the header to the document
        document.Add(header);

        // Loop through pages and align header text
        for (int i = 1; i <= pdf.GetNumberOfPages(); i++)
        {
            Rectangle pageSize = pdf.GetPage(i).GetPageSize();
            float x = pageSize.GetWidth() / 2;
            float y = pageSize.GetTop() - 20;

            // Add the header text to each page
            document.ShowTextAligned(header, x, y, i, TextAlignment.LEFT, VerticalAlignment.BOTTOM, 0);
        }

        // Set the margins
        document.SetTopMargin(50);
        document.SetBottomMargin(50);
    }
}

In the code above, we created a new PDF file called "newfile.pdf" and added a paragraph header to it.

Editing an Existing PDF File

To edit an existing PDF file using iTextSharp, you need a PdfReader object to read the existing PDF document and a PdfStamper object to modify it. Here's an example:

using iText.Kernel.Pdf;
using iText.Layout;
using iText.Layout.Element;
using iText.Layout.Properties;
using iText.Html2pdf;
using System.IO;

/**
 * iText URL to PDF
 * anchor-itext-url-to-pdf
 **/
private void ExistingWebURL()
{
    // Initialize PDF writer
    PdfWriter writer = new PdfWriter("wikipedia.pdf");

    // Initialize PDF document
    using PdfDocument pdf = new PdfDocument(writer);

    ConverterProperties properties = new ConverterProperties();
    properties.SetBaseUri("https://en.wikipedia.org/wiki/Portable_Document_Format");

    // Convert HTML to PDF
    Document document = HtmlConverter.ConvertToDocument(
        new FileStream("Test_iText7_1.pdf", FileMode.Open), pdf, properties);

    // Create and add a header paragraph
    Paragraph header = new Paragraph("HEADER")
        .SetTextAlignment(TextAlignment.CENTER)
        .SetFontSize(16);

    document.Add(header);

    // Align header text for each page
    for (int i = 1; i <= pdf.GetNumberOfPages(); i++)
    {
        Rectangle pageSize = pdf.GetPage(i).GetPageSize();
        float x = pageSize.GetWidth() / 2;
        float y = pageSize.GetTop() - 20;

        // Add header text aligned at the top
        document.ShowTextAligned(header, x, y, i, TextAlignment.LEFT, VerticalAlignment.BOTTOM, 0);
    }

    // Set the top and bottom margins
    document.SetTopMargin(50);
    document.SetBottomMargin(50);
    document.Close();
}

using iText.Kernel.Pdf;
using iText.Layout;
using iText.Layout.Element;
using iText.Layout.Properties;
using iText.Html2pdf;
using System.IO;

/**
 * iText URL to PDF
 * anchor-itext-url-to-pdf
 **/
private void ExistingWebURL()
{
    // Initialize PDF writer
    PdfWriter writer = new PdfWriter("wikipedia.pdf");

    // Initialize PDF document
    using PdfDocument pdf = new PdfDocument(writer);

    ConverterProperties properties = new ConverterProperties();
    properties.SetBaseUri("https://en.wikipedia.org/wiki/Portable_Document_Format");

    // Convert HTML to PDF
    Document document = HtmlConverter.ConvertToDocument(
        new FileStream("Test_iText7_1.pdf", FileMode.Open), pdf, properties);

    // Create and add a header paragraph
    Paragraph header = new Paragraph("HEADER")
        .SetTextAlignment(TextAlignment.CENTER)
        .SetFontSize(16);

    document.Add(header);

    // Align header text for each page
    for (int i = 1; i <= pdf.GetNumberOfPages(); i++)
    {
        Rectangle pageSize = pdf.GetPage(i).GetPageSize();
        float x = pageSize.GetWidth() / 2;
        float y = pageSize.GetTop() - 20;

        // Add header text aligned at the top
        document.ShowTextAligned(header, x, y, i, TextAlignment.LEFT, VerticalAlignment.BOTTOM, 0);
    }

    // Set the top and bottom margins
    document.SetTopMargin(50);
    document.SetBottomMargin(50);
    document.Close();
}

In this code, an existing PDF opens, and we add headers to its pages with proper text alignment.

IronPDF is a powerful PDF library for C# that facilitates editing PDF documents. This tutorial will walk through the steps to edit an existing PDF file using IronPDF, including creating new PDF documents, adding pages, merging PDFs, and more.

Prerequisites

Ensure you have:

• Visual Studio IDE
• IronPDF library

Step 1: Create a New Project

Create a new C# project in Visual Studio. Choose the "Console Application" project type.

Step 2: Install IronPDF

Use the NuGet Package Manager to install the IronPDF library into your project.

// Execute this command in the Package Manager Console
Install-Package IronPdf

// Execute this command in the Package Manager Console
Install-Package IronPdf

Step 3: Load an Existing PDF Document

Load an existing PDF document using the PdfDocument class:

using IronPdf;

// Path to an existing PDF file
var existingPdf = @"C:\path\to\existing\pdf\document.pdf";

// Load the PDF document
var pdfDoc = PdfDocument.FromFile(existingPdf);

using IronPdf;

// Path to an existing PDF file
var existingPdf = @"C:\path\to\existing\pdf\document.pdf";

// Load the PDF document
var pdfDoc = PdfDocument.FromFile(existingPdf);

Step 4: Add a New Page to an Existing PDF Document

To add a new page:

// Add a new page with default size
var newPage = pdfDoc.AddPage();
newPage.Size = PageSize.Letter;

// Add a new page with default size
var newPage = pdfDoc.AddPage();
newPage.Size = PageSize.Letter;

Step 5: Creating PDF From Website

Generate a PDF directly from a webpage URL. Here's an example:

using IronPdf;

/**
 * IronPDF URL to PDF
 * anchor-ironpdf-website-to-pdf
 **/
private void ExistingWebURL()
{
    // Create PDF from a webpage
    var Renderer = new IronPdf.ChromePdfRenderer();

    // Set rendering options
    Renderer.RenderingOptions.MarginTop = 50; // millimeters
    Renderer.RenderingOptions.MarginBottom = 50;
    Renderer.RenderingOptions.CssMediaType = IronPdf.Rendering.PdfCssMediaType.Print;
    Renderer.RenderingOptions.TextHeader = new TextHeaderFooter()
    {
        CenterText = "{pdf-title}",
        DrawDividerLine = true,
        FontSize = 16
    };
    Renderer.RenderingOptions.TextFooter = new TextHeaderFooter()
    {
        LeftText = "{date} {time}",
        RightText = "Page {page} of {total-pages}",
        DrawDividerLine = true,
        FontSize = 14
    };
    Renderer.RenderingOptions.EnableJavaScript = true;
    Renderer.RenderingOptions.RenderDelay = 500; // milliseconds

    // Render URL as PDF
    using var PDF = Renderer.RenderUrlAsPdf("https://en.wikipedia.org/wiki/Portable_Document_Format");
    PDF.SaveAs("wikipedia.pdf");
}

using IronPdf;

/**
 * IronPDF URL to PDF
 * anchor-ironpdf-website-to-pdf
 **/
private void ExistingWebURL()
{
    // Create PDF from a webpage
    var Renderer = new IronPdf.ChromePdfRenderer();

    // Set rendering options
    Renderer.RenderingOptions.MarginTop = 50; // millimeters
    Renderer.RenderingOptions.MarginBottom = 50;
    Renderer.RenderingOptions.CssMediaType = IronPdf.Rendering.PdfCssMediaType.Print;
    Renderer.RenderingOptions.TextHeader = new TextHeaderFooter()
    {
        CenterText = "{pdf-title}",
        DrawDividerLine = true,
        FontSize = 16
    };
    Renderer.RenderingOptions.TextFooter = new TextHeaderFooter()
    {
        LeftText = "{date} {time}",
        RightText = "Page {page} of {total-pages}",
        DrawDividerLine = true,
        FontSize = 14
    };
    Renderer.RenderingOptions.EnableJavaScript = true;
    Renderer.RenderingOptions.RenderDelay = 500; // milliseconds

    // Render URL as PDF
    using var PDF = Renderer.RenderUrlAsPdf("https://en.wikipedia.org/wiki/Portable_Document_Format");
    PDF.SaveAs("wikipedia.pdf");
}

Convert HTML text to a PDF using iText 7:

using iText.Html2pdf;
using System.IO;

/**
 * iText HTML to PDF
 * anchor-itext-html-to-pdf
 **/
private void HTMLString()
{
    HtmlConverter.ConvertToPdf("<h1>Hello iText7</h1>", new FileStream("iText7HtmlToPdf.pdf", FileMode.Create));
}

using iText.Html2pdf;
using System.IO;

/**
 * iText HTML to PDF
 * anchor-itext-html-to-pdf
 **/
private void HTMLString()
{
    HtmlConverter.ConvertToPdf("<h1>Hello iText7</h1>", new FileStream("iText7HtmlToPdf.pdf", FileMode.Create));
}

Performance

IronPDF is designed to be faster and more efficient than iTextSharp, allowing quicker generation of PDFs using fewer resources. This efficiency is crucial for large or complex documents.

Pricing

iTextSharp requires a commercial license for certain use cases, which can be expensive. IronPDF, however, offers a more affordable pricing model with various options tailored to different needs and budgets.