SpirePDF C# HTML to PDF Tutorial & Library Comparison

A Brief Overview of IronPDF and Spire.PDF

IronPDF is a versatile .NET PDF library designed to handle a wide range of PDF-related tasks, including converting PDF files, PDF editing, PDF creation, reading PDF files, and more. It is known for its ease of integration into existing .NET applications, high performance, and support for modern web standards like HTML5, CSS3, and JavaScript. IronPDF's API is intuitive, making it an excellent choice if you are looking to add robust PDF functionality to your projects.

Spire.PDF for .NET is another powerful .NET PDF library that provides a comprehensive set of features for PDF creation and manipulation. It supports various PDF functionalities such as text and image extraction, PDF form filling, and digital signatures. Spire.PDF is designed to be easy to use and integrates seamlessly with .NET applications, making it another potential candidate for your PDF projects.

For more detailed information about IronPDF, visit IronPDF.com.

Cross-Platform Compatibility

IronPDF

IronPDF stands out with its extensive cross-platform compatibility. It supports a wide range of environments within the .NET framework, ensuring seamless operation across different platforms. Below is a summary of IronPDF's platform compatibility:

• .NET versions:

  • Fully written in and supports C#, VB.NET, and F#
  • .NET Core (8, 7, 6, 5, and 3.1+)
  • .NET Standard (2.0+)
  • .NET Framework (4.6.2+)
• App environments: IronPDF works within various app environments such as Windows, Linux, Mac, Docker, Azure, and AWS.
• IDEs: Works with IDEs such as Microsoft Visual Studio and JetBrains Rider & ReSharper
• OS and Processors: Supports several different OS & processors including Windows, Mac, Linux, x64, x86, ARM

For more details on IronPDF's compatibility, visit the IronPDF Features Page.

Spire.PDF

Spire.PDF has full support within the .NET environment, but while it works within the Windows operating system, it lacks the native support for Linux and macOS that IronPDF has.

• .NET Support:

  • .NET Framework 2.0+
  • .NET Core 2.0+
  • Written in C#, with support for VB.NET
• App Environments: Spire.PDF works in various app environments such as Windows and ASP.NET applications. It can also support Windows Forms.

Feature Comparison: PDF Functionality in IronPDF vs. Spire.PDF

IronPDF and Spire.PDF both offer a range of features tailored for different PDF functionalities. Below is a comparison of key features provided by each library:

IronPDF Features

• PDF conversion: IronPDF can convert HTML to PDF. With its full support for modern web standards, you can be assured that IronPDF will consistently return pixel-perfect PDFs from your HTML content. IronPDF can also convert PDF files from other formats such as DOCX, images, RTF, and more.

• PDF Generation: With IronPDF, you can generate PDFs from URLs, ASPX files, or HTML strings.

• Security features: With IronPDF, you can always be assured that any sensitive PDF files are secure thanks to its security features. Use IronPDF to encrypt your PDF files, set passwords, and set permissions for your PDF files.

• PDF editing features: With IronPDF you can process existing PDF documents, edit them, and read PDF files with ease. IronPDF offers editing features such as adding headers and footers, stamping text and images onto the PDF pages, adding custom watermarks to the PDF, working with PDF forms, and splitting or merging PDF files.

• Integration: Seamlessly integrates with ASP.NET and MVC applications.

• PDF version support: Can support PDF version 1.2-1.7

For a comprehensive list of IronPDF features, visit IronPDF Features.

Spire.PDF Features

• PDF Creation: Create PDFs from scratch or existing files.
• Text and Image Extraction: Use Spire.PDF to extract PDF pages and content.
• PDF Form Handling: Fill and manage PDF forms.
• PDF Conversion: Convert PDFs to other formats like HTML, RTF, and images.
• Page Manipulation: Insert, delete, and reorder pages in a PDF.

Comparison of Top Highlight Features with Code Examples Between IronPDF vs. Spire.PDF for .NET

To illustrate the capabilities of IronPDF and Spire.PDF for .NET, we will compare their implementation of several key PDF functionalities through code examples, giving you an idea of how these features could help with your PDF projects.

Convert HTML to PDF

IronPDF Example:

using IronPdf;

// Disable local disk access or cross-origin requests
Installation.EnableWebSecurity = true;

// Instantiate Renderer
var renderer = new ChromePdfRenderer();

// Create a PDF from an HTML string using C#
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
pdf.SaveAs("output.pdf");

// Advanced Example with HTML Assets
// Load external HTML assets: images, CSS, and JavaScript.
// An optional BasePath 'C:\site\assets\' is set as the file location to load assets from
var myAdvancedPdf = renderer.RenderHtmlAsPdf("<img src='icons/iron.png'>", @"C:\site\assets\");
myAdvancedPdf.SaveAs("html-with-assets.pdf");

using IronPdf;

// Disable local disk access or cross-origin requests
Installation.EnableWebSecurity = true;

// Instantiate Renderer
var renderer = new ChromePdfRenderer();

// Create a PDF from an HTML string using C#
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
pdf.SaveAs("output.pdf");

// Advanced Example with HTML Assets
// Load external HTML assets: images, CSS, and JavaScript.
// An optional BasePath 'C:\site\assets\' is set as the file location to load assets from
var myAdvancedPdf = renderer.RenderHtmlAsPdf("<img src='icons/iron.png'>", @"C:\site\assets\");
myAdvancedPdf.SaveAs("html-with-assets.pdf");

Imports IronPdf



' Disable local disk access or cross-origin requests

Installation.EnableWebSecurity = True



' Instantiate Renderer

Dim renderer = New ChromePdfRenderer()



' Create a PDF from an HTML string using C#

Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>")

pdf.SaveAs("output.pdf")



' Advanced Example with HTML Assets

' Load external HTML assets: images, CSS, and JavaScript.

' An optional BasePath 'C:\site\assets\' is set as the file location to load assets from

Dim myAdvancedPdf = renderer.RenderHtmlAsPdf("<img src='icons/iron.png'>", "C:\site\assets\")

myAdvancedPdf.SaveAs("html-with-assets.pdf")

Spire.PDF Example:

using Spire.Pdf;
using Spire.Pdf.HtmlConverter;
using System.IO;
using System.Threading;
using System.Drawing;

namespace ConvertHtmlStringToPdfWithoutPlugin
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

            // Create a PdfPageSettings object
            PdfPageSettings setting = new PdfPageSettings();

            // Set page size and margins through the object
            setting.Size = new SizeF(1000, 1000);
            setting.Margins = new Spire.Pdf.Graphics.PdfMargins(20);

            // Create a PdfHtmlLayoutFormat object
            PdfHtmlLayoutFormat htmlLayoutFormat = new PdfHtmlLayoutFormat();

            // Set IsWaiting property to true
            htmlLayoutFormat.IsWaiting = true;

            // Read HTML string from a .html file
            string htmlString = File.ReadAllText(@"C:\Users\Administrator\Desktop\Document\Html\Sample.html");
            // Load HTML from HTML string using LoadFromHTML method
            Thread thread = new Thread(() =>
            { doc.LoadFromHTML(htmlString, true, setting, htmlLayoutFormat); });
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
            thread.Join();

            // Save to a PDF file
            doc.SaveToFile("HtmlStringToPdf.pdf");
        }
    }
}

using Spire.Pdf;
using Spire.Pdf.HtmlConverter;
using System.IO;
using System.Threading;
using System.Drawing;

namespace ConvertHtmlStringToPdfWithoutPlugin
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

            // Create a PdfPageSettings object
            PdfPageSettings setting = new PdfPageSettings();

            // Set page size and margins through the object
            setting.Size = new SizeF(1000, 1000);
            setting.Margins = new Spire.Pdf.Graphics.PdfMargins(20);

            // Create a PdfHtmlLayoutFormat object
            PdfHtmlLayoutFormat htmlLayoutFormat = new PdfHtmlLayoutFormat();

            // Set IsWaiting property to true
            htmlLayoutFormat.IsWaiting = true;

            // Read HTML string from a .html file
            string htmlString = File.ReadAllText(@"C:\Users\Administrator\Desktop\Document\Html\Sample.html");
            // Load HTML from HTML string using LoadFromHTML method
            Thread thread = new Thread(() =>
            { doc.LoadFromHTML(htmlString, true, setting, htmlLayoutFormat); });
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
            thread.Join();

            // Save to a PDF file
            doc.SaveToFile("HtmlStringToPdf.pdf");
        }
    }
}

Imports Spire.Pdf

Imports Spire.Pdf.HtmlConverter

Imports System.IO

Imports System.Threading

Imports System.Drawing



Namespace ConvertHtmlStringToPdfWithoutPlugin

	Friend Class Program

		Shared Sub Main(ByVal args() As String)

			' Create a PdfDocument object

			Dim doc As New PdfDocument()



			' Create a PdfPageSettings object

			Dim setting As New PdfPageSettings()



			' Set page size and margins through the object

			setting.Size = New SizeF(1000, 1000)

			setting.Margins = New Spire.Pdf.Graphics.PdfMargins(20)



			' Create a PdfHtmlLayoutFormat object

			Dim htmlLayoutFormat As New PdfHtmlLayoutFormat()



			' Set IsWaiting property to true

			htmlLayoutFormat.IsWaiting = True



			' Read HTML string from a .html file

			Dim htmlString As String = File.ReadAllText("C:\Users\Administrator\Desktop\Document\Html\Sample.html")

			' Load HTML from HTML string using LoadFromHTML method

			Dim thread As New Thread(Sub()

				doc.LoadFromHTML(htmlString, True, setting, htmlLayoutFormat)

			End Sub)

			thread.SetApartmentState(ApartmentState.STA)

			thread.Start()

			thread.Join()



			' Save to a PDF file

			doc.SaveToFile("HtmlStringToPdf.pdf")

		End Sub

	End Class

End Namespace

IronPDF uses Chrome's rendering engine for high-fidelity HTML to PDF conversion, ensuring an accurate representation of web content thanks to its support for modern web standards. Spire.PDF also provides robust HTML to PDF conversion but may not match the rendering precision of IronPDF, and takes a longer, more manual approach.

IronPDF offers fast, consistent HTML to PDF conversions, making it the ideal choice for efficient automation of your HTML to PDF tasks while maintaining high quality for your PDFs.

Encrypting PDF Documents

IronPDF Example:

using IronPdf;
using System;

// Open an Encrypted File, alternatively create a new PDF from HTML
var pdf = PdfDocument.FromFile("encrypted.pdf", "password");

// Edit file metadata
pdf.MetaData.Author = "Satoshi Nakamoto";
pdf.MetaData.Keywords = "SEO, Friendly";
pdf.MetaData.ModifiedDate = DateTime.Now;

// Edit file security settings
pdf.SecuritySettings.RemovePasswordsAndEncryption();
pdf.SecuritySettings.MakePdfDocumentReadOnly("secret-key");
pdf.SecuritySettings.AllowUserAnnotations = false;
pdf.SecuritySettings.AllowUserCopyPasteContent = false;
pdf.SecuritySettings.AllowUserFormData = false;
pdf.SecuritySettings.AllowUserPrinting = IronPdf.Security.PdfPrintSecurity.FullPrintRights;

// Change or set the document encryption password
pdf.Password = "my-password";
pdf.SaveAs("secured.pdf");

using IronPdf;
using System;

// Open an Encrypted File, alternatively create a new PDF from HTML
var pdf = PdfDocument.FromFile("encrypted.pdf", "password");

// Edit file metadata
pdf.MetaData.Author = "Satoshi Nakamoto";
pdf.MetaData.Keywords = "SEO, Friendly";
pdf.MetaData.ModifiedDate = DateTime.Now;

// Edit file security settings
pdf.SecuritySettings.RemovePasswordsAndEncryption();
pdf.SecuritySettings.MakePdfDocumentReadOnly("secret-key");
pdf.SecuritySettings.AllowUserAnnotations = false;
pdf.SecuritySettings.AllowUserCopyPasteContent = false;
pdf.SecuritySettings.AllowUserFormData = false;
pdf.SecuritySettings.AllowUserPrinting = IronPdf.Security.PdfPrintSecurity.FullPrintRights;

// Change or set the document encryption password
pdf.Password = "my-password";
pdf.SaveAs("secured.pdf");

Imports IronPdf

Imports System



' Open an Encrypted File, alternatively create a new PDF from HTML

Private pdf = PdfDocument.FromFile("encrypted.pdf", "password")



' Edit file metadata

pdf.MetaData.Author = "Satoshi Nakamoto"

pdf.MetaData.Keywords = "SEO, Friendly"

pdf.MetaData.ModifiedDate = DateTime.Now



' Edit file security settings

pdf.SecuritySettings.RemovePasswordsAndEncryption()

pdf.SecuritySettings.MakePdfDocumentReadOnly("secret-key")

pdf.SecuritySettings.AllowUserAnnotations = False

pdf.SecuritySettings.AllowUserCopyPasteContent = False

pdf.SecuritySettings.AllowUserFormData = False

pdf.SecuritySettings.AllowUserPrinting = IronPdf.Security.PdfPrintSecurity.FullPrintRights



' Change or set the document encryption password

pdf.Password = "my-password"

pdf.SaveAs("secured.pdf")

Spire.PDF Example:

using Spire.Pdf;
using Spire.Pdf.Security;

// Create a PdfDocument object
PdfDocument pdf = new PdfDocument();

// Load a sample PDF file
pdf.LoadFromFile(@"E:\Files\sample.pdf");

// Encrypt the PDF file with a password
pdf.Security.Encrypt("open", "permission", PdfPermissionsFlags.Print 
 PdfPermissionsFlags.CopyContent, PdfEncryptionKeySize.Key128Bit);

// Save the result file
pdf.SaveToFile("Encrypt.pdf", FileFormat.PDF);

using Spire.Pdf;
using Spire.Pdf.Security;

// Create a PdfDocument object
PdfDocument pdf = new PdfDocument();

// Load a sample PDF file
pdf.LoadFromFile(@"E:\Files\sample.pdf");

// Encrypt the PDF file with a password
pdf.Security.Encrypt("open", "permission", PdfPermissionsFlags.Print 
 PdfPermissionsFlags.CopyContent, PdfEncryptionKeySize.Key128Bit);

// Save the result file
pdf.SaveToFile("Encrypt.pdf", FileFormat.PDF);

Imports Spire.Pdf

Imports Spire.Pdf.Security



' Create a PdfDocument object

Private pdf As New PdfDocument()



' Load a sample PDF file

pdf.LoadFromFile("E:\Files\sample.pdf")



' Encrypt the PDF file with a password

pdf.Security.Encrypt("open", "permission", PdfPermissionsFlags.Print Or PdfPermissionsFlags.CopyContent, PdfEncryptionKeySize.Key128Bit)



' Save the result file

pdf.SaveToFile("Encrypt.pdf", FileFormat.PDF)

Both libraries provide easy-to-use methods for encrypting PDFs and setting the encrypted PDF documents' readability. IronPDF offers a straightforward approach while still giving you full control over the security settings of your PDF. Spire.PDF takes a slightly shorter process but still includes additional options for setting permissions.

Redacting PDF Content

IronPDF Example:

using IronPdf;

// Load the PDF document
PdfDocument pdf = PdfDocument.FromFile("novel.pdf");

// Redact 'are' phrase from all pages
pdf.RedactTextOnAllPages("are");

// Save the redacted document
pdf.SaveAs("redacted.pdf");

using IronPdf;

// Load the PDF document
PdfDocument pdf = PdfDocument.FromFile("novel.pdf");

// Redact 'are' phrase from all pages
pdf.RedactTextOnAllPages("are");

// Save the redacted document
pdf.SaveAs("redacted.pdf");

Imports IronPdf



' Load the PDF document

Private pdf As PdfDocument = PdfDocument.FromFile("novel.pdf")



' Redact 'are' phrase from all pages

pdf.RedactTextOnAllPages("are")



' Save the redacted document

pdf.SaveAs("redacted.pdf")

Spire.PDF Example for Redaction via Rectangle Overlay:

While Spire.PDF does not have a dedicated redaction tool, content can still be redacted using a manual process, as demonstrated below:

using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;

// Specify the input PDF file path
string inputPdfFilePath = "path/to/your/input.pdf";

// Specify the output redacted PDF file path
string outputPdfFilePath = "path/to/your/redacted_output.pdf";

// Create a new PdfDocument object
PdfDocument pdfDocument = new PdfDocument();

// Load the existing PDF document
pdfDocument.LoadFromFile(inputPdfFilePath);

// Redact content on each page
foreach (PdfPageBase page in pdfDocument.Pages)
{
    // Define the area to redact (e.g., coordinates and size of the rectangle)
    RectangleF redactArea = new RectangleF(100, 100, 200, 50); // Example coordinates and size

    // Apply redaction
    page.Canvas.DrawRectangle(new PdfSolidBrush(Color.Black), redactArea);
}

// Save the redacted PDF document
pdfDocument.SaveToFile(outputPdfFilePath);

using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;

// Specify the input PDF file path
string inputPdfFilePath = "path/to/your/input.pdf";

// Specify the output redacted PDF file path
string outputPdfFilePath = "path/to/your/redacted_output.pdf";

// Create a new PdfDocument object
PdfDocument pdfDocument = new PdfDocument();

// Load the existing PDF document
pdfDocument.LoadFromFile(inputPdfFilePath);

// Redact content on each page
foreach (PdfPageBase page in pdfDocument.Pages)
{
    // Define the area to redact (e.g., coordinates and size of the rectangle)
    RectangleF redactArea = new RectangleF(100, 100, 200, 50); // Example coordinates and size

    // Apply redaction
    page.Canvas.DrawRectangle(new PdfSolidBrush(Color.Black), redactArea);
}

// Save the redacted PDF document
pdfDocument.SaveToFile(outputPdfFilePath);

Imports Spire.Pdf

Imports Spire.Pdf.Graphics

Imports System.Drawing



' Specify the input PDF file path

Private inputPdfFilePath As String = "path/to/your/input.pdf"



' Specify the output redacted PDF file path

Private outputPdfFilePath As String = "path/to/your/redacted_output.pdf"



' Create a new PdfDocument object

Private pdfDocument As New PdfDocument()



' Load the existing PDF document

pdfDocument.LoadFromFile(inputPdfFilePath)



' Redact content on each page

For Each page As PdfPageBase In pdfDocument.Pages

	' Define the area to redact (e.g., coordinates and size of the rectangle)

	Dim redactArea As New RectangleF(100, 100, 200, 50) ' Example coordinates and size



	' Apply redaction

	page.Canvas.DrawRectangle(New PdfSolidBrush(Color.Black), redactArea)

Next page



' Save the redacted PDF document

pdfDocument.SaveToFile(outputPdfFilePath)

IronPDF simplifies redaction with its robust, yet straightforward, redaction tool. Spire.PDF requires more manual handling for redaction due to the absence of a built-in redaction tool, resulting in potentially less efficient workflows.

Sign PDF

IronPDF Example:

using IronPdf;
using IronPdf.Signing;
using System.Security.Cryptography.X509Certificates;

// Instantiate the renderer
ChromePdfRenderer renderer = new ChromePdfRenderer();
PdfDocument pdf = renderer.RenderHtmlAsPdf("<h1>foo</h1>");

// Create X509Certificate2 object with X509KeyStorageFlags set to Exportable
X509Certificate2 cert = new X509Certificate2("IronSoftware.pfx", "123456", X509KeyStorageFlags.Exportable);

// Create PDF digital signature with the PdfSignature object
var sig = new PdfSignature(cert);

// Sign PDF document
pdf.Sign(sig);
pdf.SaveAs("signed.pdf");

using IronPdf;
using IronPdf.Signing;
using System.Security.Cryptography.X509Certificates;

// Instantiate the renderer
ChromePdfRenderer renderer = new ChromePdfRenderer();
PdfDocument pdf = renderer.RenderHtmlAsPdf("<h1>foo</h1>");

// Create X509Certificate2 object with X509KeyStorageFlags set to Exportable
X509Certificate2 cert = new X509Certificate2("IronSoftware.pfx", "123456", X509KeyStorageFlags.Exportable);

// Create PDF digital signature with the PdfSignature object
var sig = new PdfSignature(cert);

// Sign PDF document
pdf.Sign(sig);
pdf.SaveAs("signed.pdf");

Imports IronPdf

Imports IronPdf.Signing

Imports System.Security.Cryptography.X509Certificates



' Instantiate the renderer

Private renderer As New ChromePdfRenderer()

Private pdf As PdfDocument = renderer.RenderHtmlAsPdf("<h1>foo</h1>")



' Create X509Certificate2 object with X509KeyStorageFlags set to Exportable

Private cert As New X509Certificate2("IronSoftware.pfx", "123456", X509KeyStorageFlags.Exportable)



' Create PDF digital signature with the PdfSignature object

Private sig = New PdfSignature(cert)



' Sign PDF document

pdf.Sign(sig)

pdf.SaveAs("signed.pdf")

Spire.PDF Example:

using Spire.Pdf;
using Spire.Pdf.Security;
using System.Drawing;

// Create a PdfDocument object
PdfDocument doc = new PdfDocument();

// Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf");

// Load the certificate
PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx", "e-iceblue");

// Create a PdfSignature object and specify its position and size
PdfSignature signature = new PdfSignature(doc, doc.Pages[doc.Pages.Count - 1], cert, "MySignature");
RectangleF rectangleF = new RectangleF(doc.Pages[0].ActualSize.Width - 260 - 54 , 200, 260, 110);
signature.Bounds = rectangleF;
signature.Certificated = true;

// Set the graphics mode to ImageAndSignDetail
signature.GraphicsMode = GraphicMode.SignImageAndSignDetail;

// Set various details about the signature
signature.NameLabel = "Signer:";
signature.Name = "Gary";
signature.ContactInfoLabel = "Phone:";
signature.ContactInfo = "0123456";
signature.DateLabel = "Date:";
signature.Date = DateTime.Now;
signature.LocationInfoLabel = "Location:";
signature.LocationInfo = "USA";
signature.ReasonLabel = "Reason:";
signature.Reason = "I am the author";
signature.DistinguishedNameLabel = "DN:";
signature.DistinguishedName = signature.Certificate.IssuerName.Name;

// Set the signature image source
signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\handwrittingSignature.png");

// Set the signature font
signature.SignDetailsFont = new PdfTrueTypeFont(new Font("Arial Unicode MS", 12f, FontStyle.Regular));

// Set the document permission to forbid changes but allow form fill
signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges 
 PdfCertificationFlags.AllowFormFill;

// Save to file
doc.SaveToFile("VisiableSignature.pdf");

using Spire.Pdf;
using Spire.Pdf.Security;
using System.Drawing;

// Create a PdfDocument object
PdfDocument doc = new PdfDocument();

// Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf");

// Load the certificate
PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx", "e-iceblue");

// Create a PdfSignature object and specify its position and size
PdfSignature signature = new PdfSignature(doc, doc.Pages[doc.Pages.Count - 1], cert, "MySignature");
RectangleF rectangleF = new RectangleF(doc.Pages[0].ActualSize.Width - 260 - 54 , 200, 260, 110);
signature.Bounds = rectangleF;
signature.Certificated = true;

// Set the graphics mode to ImageAndSignDetail
signature.GraphicsMode = GraphicMode.SignImageAndSignDetail;

// Set various details about the signature
signature.NameLabel = "Signer:";
signature.Name = "Gary";
signature.ContactInfoLabel = "Phone:";
signature.ContactInfo = "0123456";
signature.DateLabel = "Date:";
signature.Date = DateTime.Now;
signature.LocationInfoLabel = "Location:";
signature.LocationInfo = "USA";
signature.ReasonLabel = "Reason:";
signature.Reason = "I am the author";
signature.DistinguishedNameLabel = "DN:";
signature.DistinguishedName = signature.Certificate.IssuerName.Name;

// Set the signature image source
signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\handwrittingSignature.png");

// Set the signature font
signature.SignDetailsFont = new PdfTrueTypeFont(new Font("Arial Unicode MS", 12f, FontStyle.Regular));

// Set the document permission to forbid changes but allow form fill
signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges 
 PdfCertificationFlags.AllowFormFill;

// Save to file
doc.SaveToFile("VisiableSignature.pdf");

Imports Spire.Pdf

Imports Spire.Pdf.Security

Imports System.Drawing



' Create a PdfDocument object

Private doc As New PdfDocument()



' Load a sample PDF file

doc.LoadFromFile("C:\Users\Administrator\Desktop\sample.pdf")



' Load the certificate

Dim cert As New PdfCertificate("C:\Users\Administrator\Desktop\MyCertificate.pfx", "e-iceblue")



' Create a PdfSignature object and specify its position and size

Dim signature As New PdfSignature(doc, doc.Pages(doc.Pages.Count - 1), cert, "MySignature")

Dim rectangleF As New RectangleF(doc.Pages(0).ActualSize.Width - 260 - 54, 200, 260, 110)

signature.Bounds = rectangleF

signature.Certificated = True



' Set the graphics mode to ImageAndSignDetail

signature.GraphicsMode = GraphicMode.SignImageAndSignDetail



' Set various details about the signature

signature.NameLabel = "Signer:"

signature.Name = "Gary"

signature.ContactInfoLabel = "Phone:"

signature.ContactInfo = "0123456"

signature.DateLabel = "Date:"

signature.Date = DateTime.Now

signature.LocationInfoLabel = "Location:"

signature.LocationInfo = "USA"

signature.ReasonLabel = "Reason:"

signature.Reason = "I am the author"

signature.DistinguishedNameLabel = "DN:"

signature.DistinguishedName = signature.Certificate.IssuerName.Name



' Set the signature image source

signature.SignImageSource = PdfImage.FromFile("C:\Users\Administrator\Desktop\handwrittingSignature.png")



' Set the signature font

signature.SignDetailsFont = New PdfTrueTypeFont(New Font("Arial Unicode MS", 12F, FontStyle.Regular))



' Set the document permission to forbid changes but allow form fill

signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges Or PdfCertificationFlags.AllowFormFill



' Save to file

doc.SaveToFile("VisiableSignature.pdf")

Digitally signing PDFs can be helpful in various settings, from being used to authenticate PDF documents to simply signing off on a new project. IronPDF offers a straightforward approach to adding digital signatures, allowing easy automation of the signing process. Spire.PDF also supports digital signatures for PDFs; however, the process can be more manual and require more effort to implement.

Watermark PDF

IronPDF Example:

using IronPdf;

// Stamps a Watermark onto a new or existing PDF
var renderer = new ChromePdfRenderer();

var pdf = renderer.RenderUrlAsPdf("https://www.nuget.org/packages/IronPdf");
pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE</h2>", 30, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center);
pdf.SaveAs(@"C:\Path\To\Watermarked.pdf");

using IronPdf;

// Stamps a Watermark onto a new or existing PDF
var renderer = new ChromePdfRenderer();

var pdf = renderer.RenderUrlAsPdf("https://www.nuget.org/packages/IronPdf");
pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE</h2>", 30, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center);
pdf.SaveAs(@"C:\Path\To\Watermarked.pdf");

Imports IronPdf



' Stamps a Watermark onto a new or existing PDF

Private renderer = New ChromePdfRenderer()



Private pdf = renderer.RenderUrlAsPdf("https://www.nuget.org/packages/IronPdf")

pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE</h2>", 30, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center)

pdf.SaveAs("C:\Path\To\Watermarked.pdf")

Spire.PDF Example:

using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;

// Create a PdfDocument object
PdfDocument pdf = new PdfDocument();

// Load a sample PDF document
pdf.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.pdf");

// Create a PdfTrueTypeFont object
PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", 50f), true);

// Set the watermark text
string text = "CONFIDENTIAL";

// Measure the text size
SizeF textSize = font.MeasureString(text);

// Calculate the values of two offset variables,
// which will be used to calculate the translation amount of the coordinate system
float offset1 = (float)(textSize.Width * System.Math.Sqrt(2) / 4);
float offset2 = (float)(textSize.Height * System.Math.Sqrt(2) / 4);

// Traverse all the pages in the document
foreach (PdfPageBase page in pdf.Pages)
{
    // Set the page transparency
    page.Canvas.SetTransparency(0.8f);

    // Translate the coordinate system by specified coordinates
    page.Canvas.TranslateTransform(page.Canvas.Size.Width / 2 - offset1 - offset2, page.Canvas.Size.Height / 2 + offset1 - offset2);

    // Rotate the coordinate system 45 degrees counterclockwise
    page.Canvas.RotateTransform(-45);

    // Draw watermark text on the page
    page.Canvas.DrawString(text, font, PdfBrushes.DarkGray, 0, 0);
}

// Save the changes to another file
pdf.SaveToFile("TextWatermark.pdf");

using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;

// Create a PdfDocument object
PdfDocument pdf = new PdfDocument();

// Load a sample PDF document
pdf.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.pdf");

// Create a PdfTrueTypeFont object
PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", 50f), true);

// Set the watermark text
string text = "CONFIDENTIAL";

// Measure the text size
SizeF textSize = font.MeasureString(text);

// Calculate the values of two offset variables,
// which will be used to calculate the translation amount of the coordinate system
float offset1 = (float)(textSize.Width * System.Math.Sqrt(2) / 4);
float offset2 = (float)(textSize.Height * System.Math.Sqrt(2) / 4);

// Traverse all the pages in the document
foreach (PdfPageBase page in pdf.Pages)
{
    // Set the page transparency
    page.Canvas.SetTransparency(0.8f);

    // Translate the coordinate system by specified coordinates
    page.Canvas.TranslateTransform(page.Canvas.Size.Width / 2 - offset1 - offset2, page.Canvas.Size.Height / 2 + offset1 - offset2);

    // Rotate the coordinate system 45 degrees counterclockwise
    page.Canvas.RotateTransform(-45);

    // Draw watermark text on the page
    page.Canvas.DrawString(text, font, PdfBrushes.DarkGray, 0, 0);
}

// Save the changes to another file
pdf.SaveToFile("TextWatermark.pdf");

Imports System

Imports Spire.Pdf

Imports Spire.Pdf.Graphics

Imports System.Drawing



' Create a PdfDocument object

Private pdf As New PdfDocument()



' Load a sample PDF document

pdf.LoadFromFile("C:\Users\Administrator\Desktop\sample.pdf")



' Create a PdfTrueTypeFont object

Dim font As New PdfTrueTypeFont(New Font("Arial", 50F), True)



' Set the watermark text

Dim text As String = "CONFIDENTIAL"



' Measure the text size

Dim textSize As SizeF = font.MeasureString(text)



' Calculate the values of two offset variables,

' which will be used to calculate the translation amount of the coordinate system

Dim offset1 As Single = CSng(textSize.Width * Math.Sqrt(2) / 4)

Dim offset2 As Single = CSng(textSize.Height * Math.Sqrt(2) / 4)



' Traverse all the pages in the document

For Each page As PdfPageBase In pdf.Pages

	' Set the page transparency

	page.Canvas.SetTransparency(0.8F)



	' Translate the coordinate system by specified coordinates

	page.Canvas.TranslateTransform(page.Canvas.Size.Width \ 2 - offset1 - offset2, page.Canvas.Size.Height \ 2 + offset1 - offset2)



	' Rotate the coordinate system 45 degrees counterclockwise

	page.Canvas.RotateTransform(-45)



	' Draw watermark text on the page

	page.Canvas.DrawString(text, font, PdfBrushes.DarkGray, 0, 0)

Next page



' Save the changes to another file

pdf.SaveToFile("TextWatermark.pdf")

IronPDF provides an easy method for adding text watermarks while giving you full control over the position and design of the watermark. IronPDF's use of HTML and CSS makes the process easier if you have experience with these languages. Spire.PDF's approach is longer with a more manual process but still provides a strong watermarking tool with full control over the design and position.

Stamping Image HTML Text

IronPDF Example:

using IronPdf;
using IronPdf.Editing;

// Instantiate Renderer
ChromePdfRenderer renderer = new ChromePdfRenderer();
PdfDocument pdf = renderer.RenderHtmlAsPdf("<h1>Example HTML Document!</h1>");

// Create text stamper
TextStamper textStamper = new TextStamper()
{
    Text = "Text Stamper!",
    FontFamily = "Bungee Spice",
    UseGoogleFont = true,
    FontSize = 30,
    IsBold = true,
    IsItalic = true,
    VerticalAlignment = VerticalAlignment.Top,
};

// Stamp the text stamper
pdf.ApplyStamp(textStamper);
pdf.SaveAs("stampText.pdf");

// Create image stamper
ImageStamper imageStamper = new ImageStamper(new Uri("https://ironpdf.com/img/svgs/iron-pdf-logo.svg"))
{
    VerticalAlignment = VerticalAlignment.Top,
};

// Stamp the image stamper
pdf.ApplyStamp(imageStamper, 0);
pdf.SaveAs("stampImage.pdf");

using IronPdf;
using IronPdf.Editing;

// Instantiate Renderer
ChromePdfRenderer renderer = new ChromePdfRenderer();
PdfDocument pdf = renderer.RenderHtmlAsPdf("<h1>Example HTML Document!</h1>");

// Create text stamper
TextStamper textStamper = new TextStamper()
{
    Text = "Text Stamper!",
    FontFamily = "Bungee Spice",
    UseGoogleFont = true,
    FontSize = 30,
    IsBold = true,
    IsItalic = true,
    VerticalAlignment = VerticalAlignment.Top,
};

// Stamp the text stamper
pdf.ApplyStamp(textStamper);
pdf.SaveAs("stampText.pdf");

// Create image stamper
ImageStamper imageStamper = new ImageStamper(new Uri("https://ironpdf.com/img/svgs/iron-pdf-logo.svg"))
{
    VerticalAlignment = VerticalAlignment.Top,
};

// Stamp the image stamper
pdf.ApplyStamp(imageStamper, 0);
pdf.SaveAs("stampImage.pdf");

Imports IronPdf

Imports IronPdf.Editing



' Instantiate Renderer

Private renderer As New ChromePdfRenderer()

Private pdf As PdfDocument = renderer.RenderHtmlAsPdf("<h1>Example HTML Document!</h1>")



' Create text stamper

Private textStamper As New TextStamper() With {

	.Text = "Text Stamper!",

	.FontFamily = "Bungee Spice",

	.UseGoogleFont = True,

	.FontSize = 30,

	.IsBold = True,

	.IsItalic = True,

	.VerticalAlignment = VerticalAlignment.Top

}



' Stamp the text stamper

pdf.ApplyStamp(textStamper)

pdf.SaveAs("stampText.pdf")



' Create image stamper

Dim imageStamper As New ImageStamper(New Uri("https://ironpdf.com/img/svgs/iron-pdf-logo.svg")) With {.VerticalAlignment = VerticalAlignment.Top}



' Stamp the image stamper

pdf.ApplyStamp(imageStamper, 0)

pdf.SaveAs("stampImage.pdf")

Spire.PDF (Text Stamping Example):

using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;

// Assumes a PdfDocument is already loaded as `page` object
PdfGraphicsState state = page.Canvas.Save();

// Define font and brushes for different effects
PdfFont font = new PdfFont(PdfFontFamily.Helvetica, 18f);
PdfSolidBrush brush1 = new PdfSolidBrush(Color.DeepSkyBlue);
PdfSolidBrush brush2 = new PdfSolidBrush(Color.CadetBlue);

// Apply transformations and draw strings with shadow and effect
page.Canvas.TranslateTransform(20, 200);
page.Canvas.ScaleTransform(1f, 0.6f);
page.Canvas.SkewTransform(-10, 0);
page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush1, 0, 0);
page.Canvas.SkewTransform(10, 0);
page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush2, 0, 0);
page.Canvas.ScaleTransform(1f, -1f);
page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush2, 0, -2 * 18);

// Restore graphics to previous state
page.Canvas.Restore(state);

using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;

// Assumes a PdfDocument is already loaded as `page` object
PdfGraphicsState state = page.Canvas.Save();

// Define font and brushes for different effects
PdfFont font = new PdfFont(PdfFontFamily.Helvetica, 18f);
PdfSolidBrush brush1 = new PdfSolidBrush(Color.DeepSkyBlue);
PdfSolidBrush brush2 = new PdfSolidBrush(Color.CadetBlue);

// Apply transformations and draw strings with shadow and effect
page.Canvas.TranslateTransform(20, 200);
page.Canvas.ScaleTransform(1f, 0.6f);
page.Canvas.SkewTransform(-10, 0);
page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush1, 0, 0);
page.Canvas.SkewTransform(10, 0);
page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush2, 0, 0);
page.Canvas.ScaleTransform(1f, -1f);
page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush2, 0, -2 * 18);

// Restore graphics to previous state
page.Canvas.Restore(state);

Imports Spire.Pdf

Imports Spire.Pdf.Graphics

Imports System.Drawing



' Assumes a PdfDocument is already loaded as `page` object

Private state As PdfGraphicsState = page.Canvas.Save()



' Define font and brushes for different effects

Private font As New PdfFont(PdfFontFamily.Helvetica, 18F)

Private brush1 As New PdfSolidBrush(Color.DeepSkyBlue)

Private brush2 As New PdfSolidBrush(Color.CadetBlue)



' Apply transformations and draw strings with shadow and effect

page.Canvas.TranslateTransform(20, 200)

page.Canvas.ScaleTransform(1F, 0.6F)

page.Canvas.SkewTransform(-10, 0)

page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush1, 0, 0)

page.Canvas.SkewTransform(10, 0)

page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush2, 0, 0)

page.Canvas.ScaleTransform(1F, -1F)

page.Canvas.DrawString("Go! Turn Around! Go! Go! Go!", font, brush2, 0, -2 * 18)



' Restore graphics to previous state

page.Canvas.Restore(state)

IronPDF's text and image stamping tool is a powerful, easy-to-use stamping tool that follows an approach similar to HTML and CSS when you apply the stamped content. While Spire.PDF also offers a basic text stamping tool, it requires more effort to apply the stamped text to your PDF files.

DOCX to PDF

IronPDF Example:

using IronPdf;

// Instantiate Renderer
DocxToPdfRenderer renderer = new DocxToPdfRenderer();

// Render from DOCX file
PdfDocument pdf = renderer.RenderDocxAsPdf("Modern-chronological-resume.docx");

// Save the PDF
pdf.SaveAs("pdfFromDocx.pdf");

using IronPdf;

// Instantiate Renderer
DocxToPdfRenderer renderer = new DocxToPdfRenderer();

// Render from DOCX file
PdfDocument pdf = renderer.RenderDocxAsPdf("Modern-chronological-resume.docx");

// Save the PDF
pdf.SaveAs("pdfFromDocx.pdf");

Imports IronPdf



' Instantiate Renderer

Private renderer As New DocxToPdfRenderer()



' Render from DOCX file

Private pdf As PdfDocument = renderer.RenderDocxAsPdf("Modern-chronological-resume.docx")



' Save the PDF

pdf.SaveAs("pdfFromDocx.pdf")

Spire.PDF Using Spire.Doc for DOCX to PDF Conversion:

Spire.PDF itself cannot convert DOCX to PDF; however, the Spire.Doc library can be used to handle this conversion, and then you can use Spire.PDF to work on the resultant PDF.

using Spire.Doc;

// Create a Document object
Document doc = new Document();

// Load a Word document
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Sample.docx");

// Save the document to PDF
doc.SaveToFile("ToPDF.pdf", FileFormat.PDF);

// Dispose of resources
doc.Dispose();

using Spire.Doc;

// Create a Document object
Document doc = new Document();

// Load a Word document
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Sample.docx");

// Save the document to PDF
doc.SaveToFile("ToPDF.pdf", FileFormat.PDF);

// Dispose of resources
doc.Dispose();

Imports Spire.Doc



' Create a Document object

Private doc As New Document()



' Load a Word document

doc.LoadFromFile("C:\Users\Administrator\Desktop\Sample.docx")



' Save the document to PDF

doc.SaveToFile("ToPDF.pdf", FileFormat.PDF)



' Dispose of resources

doc.Dispose()

IronPDF offers built-in support for direct DOCX to PDF conversion, meaning you save time without needing additional libraries to handle this task. Spire.PDF, on the other hand, cannot directly handle DOCX to PDF conversion, requiring the Spire.Doc library to convert DOCX files to PDF.

Summary of the Code Examples Comparison

Below is a comparison table summarizing the key differences in code implementation between IronPDF and Spire.PDF for .NET:

Pricing and Licensing: IronPDF vs. Spire.PDF for .NET Library

IronPDF Pricing and Licensing

IronPDF offers various levels and additional features for purchasing a license. Developers can also buy Iron Suite which gives access to all of IronSoftware’s products at the price of two. If you’re not ready to buy a license, IronPDF provides a free trial that lasts 30 days.

• Perpetual licenses: Offers a range of perpetual licenses depending on the size of your team, your project needs, and the number of locations. Each license type comes with email support.

• Lite License: This license costs $749 and supports one developer, one location, and one project.

• Plus License: Supporting three developers, three locations, and three projects, this is the next step up from the lite license and costs $1,499. The Plus license offers chat support and phone support in addition to basic email support.

• Professional License: This license is suitable for larger teams, supporting ten developers, ten locations, and ten projects for $2,999. It offers the same contact support channels as the previous tiers but also offers screen-sharing support.

• Royalty-free redistribution: IronPDF's licensing also offers royalty-free redistribution coverage for an extra $1,999

• Uninterrupted product support: IronPDF offers access to ongoing product updates, security feature upgrades, and support from their engineering team for either $999/year or a one-time purchase of $1,999 for a 5-year coverage.

• Iron Suite: For $1,498, you get access to all Iron Software products including IronPDF, IronOCR, IronWord, IronXL, IronBarcode, IronQR, IronZIP, IronPrint, and IronWebScraper.

Spire.PDF Pricing and Licensing

Spire.PDF offers a range of licenses depending on your needs.

• Free version: Spire.PDF offers a free version limited to 10 PDF pages; beyond this, you would need to purchase a paid license.
• Developer Subscription: Priced at either $999 or $1,199 per year depending on the type of support you need, this option is for developers who need to build PDF-related features but don’t require OEM distribution rights.
• Developer OEM Subscription: Costs around $2,549 - $4,248 per year depending on the amount of support you need, and includes free upgrades, premium support, and the ability to distribute the application to end-users.
• Site Small Business: Priced at either $4,599 or $7,598 depending on the support you want, this licensing tier supports up to 10 developers across up to 10 locations, updates for 1 year, and free online technical resources.
• Site OEM Subscription: Costs $13,088 - $16,687 per year depending on the type of support you need and is aimed at larger enterprises that need to deploy applications to multiple locations.

Documentation and Support: IronPDF vs. Spire.PDF for .NET

IronPDF

IronPDF excels in providing extensive documentation and support:

• Comprehensive Documentation: Extensive and user-friendly documentation covering all features.
• 24/5 Support: Active engineer support is available.
• Video Tutorials: Step-by-step video guides are available on YouTube.
• Community Forum: Engaged community for additional support.
• Regular Updates: Monthly product updates to ensure the latest features and security patches.
• PDF API reference: Offers API references so you can get the most out of what our tools have to offer.

For more information, check out IronPDF's extensive documentation, and visit the Iron Software YouTube Channel.

Spire.PDF for .NET Documentation and Support

• Forums: Spire.PDF has a forum where users can interact with one another, sharing tips, uses, and issues encountered with Spire.PDF.
• Code Samples: Spire.PDF offers code examples on their website to show how to use the product in various use cases.
• Newsletters: Spire.PDF offers a developer's newsletter for update announcements and other important information.
• Support: Spire.PDF offers varying levels of support and response times depending on the licensing version you hold.

Conclusion

In conclusion, IronPDF and Spire.PDF for .NET are powerful tools for handling PDF documents in .NET applications. IronPDF excels in ease of use, cross-platform compatibility, and support for modern web standards, making it a preferred choice if you are looking to step up your game when working with PDF documents. Spire.PDF offers a comprehensive set of features but may require more effort for complex tasks and may lack the rich, extensive set of features that IronPDF has to offer.

You can try the 30-day free trial to check out their available features.