How to Migrate from Pdfium to IronPDF in C#

Understanding the PDFium .NET Wrappers

PDFium is Google's BSD-3-Clause C++ PDF rendering and parsing engine—the same engine that powers Chrome's built-in PDF viewer. There is no official Google-supplied .NET binding; instead, the .NET ecosystem consumes PDFium through community wrappers. The four most commonly cited NuGet packages are PdfiumViewer (pvginkel; Apache 2.0; archived August 2019, last release 2.13.0 in November 2017, .NET Framework 2.0+), PdfiumViewer.Updated (a maintained fork ported to .NET Core / .NET 6), PDFiumCore (Dtronix; .NET Standard 2.1 P/Invoke bindings), and Pdfium.Net.SDK (Patagames; commercial, perpetual-license SDK).

Their APIs differ, but they share one trait: PDFium itself is a rendering and parsing engine, not an HTML-to-PDF or document-authoring engine. PDFium has no HTML parser, so no wrapper can convert HTML to PDF on its own. This guide uses PdfiumViewer as the representative wrapper for "before" snippets because its API is the most widely cited; the migration approach is the same for any of the four.

Critical PDFium Wrapper Limitations

1. Rendering-First: PDFium has no HTML parser, so no wrapper can create PDFs from HTML, URLs, or arbitrary images.

2. Limited Manipulation in Open-Source Wrappers: PdfiumViewer / PDFiumCore expose viewing and per-page text extraction; merge / split / form-edit is partial in Patagames Pdfium.Net.SDK and largely absent in the free wrappers.

3. Native Binary Dependencies: Requires platform-specific PDFium binaries (pdfium.dll / .so / .dylib) per RID.

4. Deployment Complexity: Must bundle and manage native binaries per platform with x86, x64, and runtimes folders.

5. Basic Text Extraction: PdfiumViewer exposes per-page raw text via GetPdfText(int); layout / format metadata is not exposed.

6. No HTML to PDF: PDFium has no HTML parser; web content cannot be converted directly.

7. No Built-in Headers/Footers: No high-level page-overlay API.

8. No Built-in Watermarks: No stamping primitive.

9. Forms: Read-only or absent in the free wrappers; available in Patagames Pdfium.Net.SDK.

10. Security: Encryption / permissions not exposed by the free wrappers; available in Patagames Pdfium.Net.SDK.

PDFium Wrappers vs IronPDF Comparison

For teams targeting modern .NET, IronPDF provides a fully managed foundation that eliminates native binary management while adding comprehensive PDF creation and manipulation capabilities.

Prerequisites

1. .NET Environment: .NET Framework 4.6.2+ or .NET Core 3.1+ / .NET 5/6/7/8/9+
2. NuGet Access: Ability to install NuGet packages
3. IronPDF License: Obtain your license key from ironpdf.com

NuGet Package Changes

# Remove whichever PDFium wrapper you used:
#   PdfiumViewer            (Apache 2.0 - archived 2019, .NET Framework only)
#   PdfiumViewer.Updated    (community fork, .NET Core / .NET 6)
#   PDFiumCore              (Dtronix - .NET Standard 2.1 P/Invoke bindings)
#   Pdfium.Net.SDK          (Patagames - commercial, perpetual license)
dotnet remove package PdfiumViewer
dotnet remove package PdfiumViewer.Updated
dotnet remove package PDFiumCore
dotnet remove package Pdfium.Net.SDK

# Install IronPDF
dotnet add package IronPdf

# Remove whichever PDFium wrapper you used:
#   PdfiumViewer            (Apache 2.0 - archived 2019, .NET Framework only)
#   PdfiumViewer.Updated    (community fork, .NET Core / .NET 6)
#   PDFiumCore              (Dtronix - .NET Standard 2.1 P/Invoke bindings)
#   Pdfium.Net.SDK          (Patagames - commercial, perpetual license)
dotnet remove package PdfiumViewer
dotnet remove package PdfiumViewer.Updated
dotnet remove package PDFiumCore
dotnet remove package Pdfium.Net.SDK

# Install IronPDF
dotnet add package IronPdf

License Configuration

// Add at application startup (Program.cs or Startup.cs)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

// Add at application startup (Program.cs or Startup.cs)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

' Add at application startup (Program.vb or Startup.vb)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

Identify PDFium Wrapper Usage

# Find PDFium wrapper usage
grep -rE "PdfiumViewer|PDFiumCore|Patagames\.Pdf|PdfDocument\.Load|\.Render\(" --include="*.cs" .

# Find native binary references
grep -rE "pdfium\.dll|libpdfium\.(so|dylib)" --include="*.csproj" --include="*.config" .

# Find platform-specific code
grep -rE "#if.*64|WIN32|WIN64|LINUX|OSX" --include="*.cs" .

# Find PDFium wrapper usage
grep -rE "PdfiumViewer|PDFiumCore|Patagames\.Pdf|PdfDocument\.Load|\.Render\(" --include="*.cs" .

# Find native binary references
grep -rE "pdfium\.dll|libpdfium\.(so|dylib)" --include="*.csproj" --include="*.config" .

# Find platform-specific code
grep -rE "#if.*64|WIN32|WIN64|LINUX|OSX" --include="*.cs" .

Namespace Changes

// PDFium wrappers (use the one you installed)
using PdfiumViewer;             // PdfiumViewer / PdfiumViewer.Updated
using PDFiumCore;               // Dtronix PDFiumCore (P/Invoke bindings)
using Patagames.Pdf;            // Patagames Pdfium.Net.SDK
using Patagames.Pdf.Net;        // Patagames Pdfium.Net.SDK

// IronPDF
using IronPdf;
using IronPdf.Rendering;
using IronPdf.Editing;

// PDFium wrappers (use the one you installed)
using PdfiumViewer;             // PdfiumViewer / PdfiumViewer.Updated
using PDFiumCore;               // Dtronix PDFiumCore (P/Invoke bindings)
using Patagames.Pdf;            // Patagames Pdfium.Net.SDK
using Patagames.Pdf.Net;        // Patagames Pdfium.Net.SDK

// IronPDF
using IronPdf;
using IronPdf.Rendering;
using IronPdf.Editing;

Imports PdfiumViewer ' PdfiumViewer / PdfiumViewer.Updated
Imports PDFiumCore ' Dtronix PDFiumCore (P/Invoke bindings)
Imports Patagames.Pdf ' Patagames Pdfium.Net.SDK
Imports Patagames.Pdf.Net ' Patagames Pdfium.Net.SDK

Imports IronPdf
Imports IronPdf.Rendering
Imports IronPdf.Editing

Core Class Mappings

Document Loading Mappings

Document Properties Mappings

Text Extraction Mappings

Saving Documents Mappings

Page Rendering Mappings

New Features Not Available in PDFium Wrappers

Example 1: Text Extraction from PDF

Before (PdfiumViewer):

// NuGet: Install-Package PdfiumViewer  (Apache 2.0; archived Aug 2019, .NET Framework 2.0+)
//        or Install-Package PdfiumViewer.Updated  (maintained fork, .NET Core / .NET 6)
//        or Install-Package PDFiumCore             (Dtronix, .NET Standard 2.1 P/Invoke)
//        or Install-Package Pdfium.Net.SDK         (Patagames, commercial perpetual license)
using PdfiumViewer;
using System;
using System.IO;
using System.Text;

class Program
{
    static void Main()
    {
        string pdfPath = "document.pdf";

        using (var document = PdfDocument.Load(pdfPath))
        {
            StringBuilder text = new StringBuilder();

            for (int i = 0; i < document.PageCount; i++)
            {
                // PdfiumViewer's text extraction is per-page raw text via GetPdfText(int).
                // No layout / format metadata is exposed.
                string pageText = document.GetPdfText(i);
                text.AppendLine(pageText);
            }

            Console.WriteLine(text.ToString());
        }
    }
}

// NuGet: Install-Package PdfiumViewer  (Apache 2.0; archived Aug 2019, .NET Framework 2.0+)
//        or Install-Package PdfiumViewer.Updated  (maintained fork, .NET Core / .NET 6)
//        or Install-Package PDFiumCore             (Dtronix, .NET Standard 2.1 P/Invoke)
//        or Install-Package Pdfium.Net.SDK         (Patagames, commercial perpetual license)
using PdfiumViewer;
using System;
using System.IO;
using System.Text;

class Program
{
    static void Main()
    {
        string pdfPath = "document.pdf";

        using (var document = PdfDocument.Load(pdfPath))
        {
            StringBuilder text = new StringBuilder();

            for (int i = 0; i < document.PageCount; i++)
            {
                // PdfiumViewer's text extraction is per-page raw text via GetPdfText(int).
                // No layout / format metadata is exposed.
                string pageText = document.GetPdfText(i);
                text.AppendLine(pageText);
            }

            Console.WriteLine(text.ToString());
        }
    }
}

Imports PdfiumViewer
Imports System
Imports System.IO
Imports System.Text

Module Program
    Sub Main()
        Dim pdfPath As String = "document.pdf"

        Using document = PdfDocument.Load(pdfPath)
            Dim text As New StringBuilder()

            For i As Integer = 0 To document.PageCount - 1
                ' PdfiumViewer's text extraction is per-page raw text via GetPdfText(int).
                ' No layout / format metadata is exposed.
                Dim pageText As String = document.GetPdfText(i)
                text.AppendLine(pageText)
            Next

            Console.WriteLine(text.ToString())
        End Using
    End Sub
End Module

After (IronPDF):

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        string pdfPath = "document.pdf";

        var pdf = PdfDocument.FromFile(pdfPath);
        string text = pdf.ExtractAllText();

        Console.WriteLine(text);
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        string pdfPath = "document.pdf";

        var pdf = PdfDocument.FromFile(pdfPath);
        string text = pdf.ExtractAllText();

        Console.WriteLine(text);
    }
}

Imports IronPdf
Imports System

Class Program
    Shared Sub Main()
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

        Dim pdfPath As String = "document.pdf"

        Dim pdf = PdfDocument.FromFile(pdfPath)
        Dim text As String = pdf.ExtractAllText()

        Console.WriteLine(text)
    End Sub
End Class

The difference here is significant. PdfiumViewer requires a manual loop through each page with GetPdfText(int), building a StringBuilder and managing the using statement for proper disposal—and the returned text is raw per-page text with no layout / format metadata.

IronPDF simplifies this to a few lines: load with PdfDocument.FromFile(), extract with ExtractAllText(), and output. The ExtractAllText() method handles all pages automatically. If you need per-page extraction, you can use pdf.Pages[index].Text. See the text extraction documentation for additional options.

Example 2: PDF Merging

Before (PdfiumViewer):

// NuGet: Install-Package PdfiumViewer  (representative open-source PDFium wrapper)
// PdfiumViewer and PDFiumCore do not expose PDF merge APIs - PDFium itself
// is a rendering / parsing engine, not a document-authoring engine.
// (Patagames Pdfium.Net.SDK exposes some document-edit operations but is commercial.)
using PdfiumViewer;
using System;
using System.IO;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        List<string> pdfFiles = new List<string>
        {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        };

        // To merge PDFs from a PDFium wrapper you must reach for another library
        // (PdfSharp, iText, IronPDF) or, with Patagames Pdfium.Net.SDK, use its
        // document-edit APIs.

        Console.WriteLine("PDF merging is not supported by PdfiumViewer / PDFiumCore.");
    }
}

// NuGet: Install-Package PdfiumViewer  (representative open-source PDFium wrapper)
// PdfiumViewer and PDFiumCore do not expose PDF merge APIs - PDFium itself
// is a rendering / parsing engine, not a document-authoring engine.
// (Patagames Pdfium.Net.SDK exposes some document-edit operations but is commercial.)
using PdfiumViewer;
using System;
using System.IO;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        List<string> pdfFiles = new List<string>
        {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        };

        // To merge PDFs from a PDFium wrapper you must reach for another library
        // (PdfSharp, iText, IronPDF) or, with Patagames Pdfium.Net.SDK, use its
        // document-edit APIs.

        Console.WriteLine("PDF merging is not supported by PdfiumViewer / PDFiumCore.");
    }
}

Imports PdfiumViewer
Imports System
Imports System.IO
Imports System.Collections.Generic

Module Program
    Sub Main()
        Dim pdfFiles As New List(Of String) From {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        }

        ' To merge PDFs from a PDFium wrapper you must reach for another library
        ' (PdfSharp, iText, IronPDF) or, with Patagames Pdfium.Net.SDK, use its
        ' document-edit APIs.

        Console.WriteLine("PDF merging is not supported by PdfiumViewer / PDFiumCore.")
    End Sub
End Module

After (IronPDF):

// NuGet: Install-Package IronPdf
using IronPdf;
using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        List<string> pdfFiles = new List<string>
        {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        };

        // PdfDocument.Merge accepts an IEnumerable<PdfDocument>, so load each file first.
        var docs = pdfFiles.Select(path => PdfDocument.FromFile(path)).ToList();
        var merged = PdfDocument.Merge(docs);
        merged.SaveAs("merged.pdf");

        Console.WriteLine("PDFs merged successfully");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        List<string> pdfFiles = new List<string>
        {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        };

        // PdfDocument.Merge accepts an IEnumerable<PdfDocument>, so load each file first.
        var docs = pdfFiles.Select(path => PdfDocument.FromFile(path)).ToList();
        var merged = PdfDocument.Merge(docs);
        merged.SaveAs("merged.pdf");

        Console.WriteLine("PDFs merged successfully");
    }
}

Imports IronPdf
Imports System
Imports System.Collections.Generic
Imports System.Linq

Module Program
    Sub Main()
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

        Dim pdfFiles As New List(Of String) From {
            "document1.pdf",
            "document2.pdf",
            "document3.pdf"
        }

        ' PdfDocument.Merge accepts an IEnumerable(Of PdfDocument), so load each file first.
        Dim docs = pdfFiles.Select(Function(path) PdfDocument.FromFile(path)).ToList()
        Dim merged = PdfDocument.Merge(docs)
        merged.SaveAs("merged.pdf")

        Console.WriteLine("PDFs merged successfully")
    End Sub
End Module

This example highlights a capability gap. Free PDFium wrappers (PdfiumViewer, PDFiumCore) do not expose merge APIs; Patagames Pdfium.Net.SDK exposes some document-edit operations but is commercial.

IronPDF provides native merging with the static PdfDocument.Merge() method, which takes an IEnumerable<PdfDocument>—load each input file with PdfDocument.FromFile() first, then merge the resulting documents. The result is a new PdfDocument that you save with SaveAs(). Learn more about merging and splitting PDFs.

Example 3: HTML to PDF Conversion

Before (PdfiumViewer):

// NuGet: Install-Package PdfiumViewer  (representative PDFium wrapper)
// PDFium is a PDF rendering / parsing engine. It has NO HTML parser, so no
// PDFium .NET wrapper (PdfiumViewer, PdfiumViewer.Updated, PDFiumCore,
// Pdfium.Net.SDK) can convert HTML to PDF on its own.
using PdfiumViewer;
using System;
using System.IO;
using System.Drawing.Printing;

class Program
{
    static void Main()
    {
        // PDFium has no native HTML-to-PDF capability.
        // Produce the PDF with another engine (wkhtmltopdf, headless Chromium,
        // IronPDF, etc.) and then load it with PdfDocument.Load(...) for rendering.
        string htmlContent = "<h1>Hello World</h1>";

        Console.WriteLine("HTML to PDF conversion is not supported by PDFium.");
    }
}

// NuGet: Install-Package PdfiumViewer  (representative PDFium wrapper)
// PDFium is a PDF rendering / parsing engine. It has NO HTML parser, so no
// PDFium .NET wrapper (PdfiumViewer, PdfiumViewer.Updated, PDFiumCore,
// Pdfium.Net.SDK) can convert HTML to PDF on its own.
using PdfiumViewer;
using System;
using System.IO;
using System.Drawing.Printing;

class Program
{
    static void Main()
    {
        // PDFium has no native HTML-to-PDF capability.
        // Produce the PDF with another engine (wkhtmltopdf, headless Chromium,
        // IronPDF, etc.) and then load it with PdfDocument.Load(...) for rendering.
        string htmlContent = "<h1>Hello World</h1>";

        Console.WriteLine("HTML to PDF conversion is not supported by PDFium.");
    }
}

Imports PdfiumViewer
Imports System
Imports System.IO
Imports System.Drawing.Printing

Module Program
    Sub Main()
        ' PDFium has no native HTML-to-PDF capability.
        ' Produce the PDF with another engine (wkhtmltopdf, headless Chromium,
        ' IronPDF, etc.) and then load it with PdfDocument.Load(...) for rendering.
        Dim htmlContent As String = "<h1>Hello World</h1>"

        Console.WriteLine("HTML to PDF conversion is not supported by PDFium.")
    End Sub
End Module

After (IronPDF):

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        var renderer = new ChromePdfRenderer();
        string htmlContent = "<h1>Hello World</h1>";

        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");

        Console.WriteLine("PDF created successfully");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

        var renderer = new ChromePdfRenderer();
        string htmlContent = "<h1>Hello World</h1>";

        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");

        Console.WriteLine("PDF created successfully");
    }
}

Imports IronPdf
Imports System

Module Program
    Sub Main()
        IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

        Dim renderer As New ChromePdfRenderer()
        Dim htmlContent As String = "<h1>Hello World</h1>"

        Dim pdf = renderer.RenderHtmlAsPdf(htmlContent)
        pdf.SaveAs("output.pdf")

        Console.WriteLine("PDF created successfully")
    End Sub
End Module

This example demonstrates the most significant capability difference. PDFium has no HTML parser, so no .NET wrapper around it can convert HTML to PDF on its own.

IronPDF provides native HTML to PDF conversion through ChromePdfRenderer, which uses a Chromium engine internally for accurate rendering of HTML, CSS, and JavaScript. The RenderHtmlAsPdf() method converts HTML strings directly to PDF documents. IronPDF can also render URLs with RenderUrlAsPdf() and HTML files with RenderHtmlFileAsPdf(). See the HTML to PDF documentation for comprehensive examples.

Before (PDFium wrapper) - Complex Deployment

MyApp/
├── bin/
│   ├── MyApp.dll
│   ├── PdfiumViewer.dll      # or PDFiumCore.dll / Patagames.Pdf.dll
│   ├── x86/
│   │   └── pdfium.dll
│   └── x64/
│       └── pdfium.dll
├── runtimes/
│   ├── win-x86/native/
│   │   └── pdfium.dll
│   ├── win-x64/native/
│   │   └── pdfium.dll
│   ├── linux-x64/native/
│   │   └── libpdfium.so
│   └── osx-x64/native/
│       └── libpdfium.dylib

After (IronPDF) - Clean Deployment

MyApp/
├── bin/
│   ├── MyApp.dll
│   └── IronPdf.dll  # Everything included

Remove Native Binary References

# Delete native PDFium binaries
rm -rf x86/ x64/ runtimes/

# Remove from .csproj
# Delete any <Content Include="pdfium.dll" /> entries
# Delete any <None Include="x86/pdfium.dll" /> entries

# Delete native PDFium binaries
rm -rf x86/ x64/ runtimes/

# Remove from .csproj
# Delete any <Content Include="pdfium.dll" /> entries
# Delete any <None Include="x86/pdfium.dll" /> entries

Scale to DPI Conversion

PdfiumViewer's Render(...) takes explicit dpiX/dpiY and PDFium's underlying rendering is scale-driven (1.0 = 72 DPI). IronPDF uses DPI directly:

// Formula: IronPDF DPI = 72 × PDFium scale
// PDFium scale 2.0 → IronPDF DPI 144
pdf.RasterizeToImageFiles("*.png", DPI: 144);

// Formula: IronPDF DPI = 72 × PDFium scale
// PDFium scale 2.0 → IronPDF DPI 144
pdf.RasterizeToImageFiles("*.png", DPI: 144);

' Formula: IronPDF DPI = 72 × PDFium scale
' PDFium scale 2.0 → IronPDF DPI 144
pdf.RasterizeToImageFiles("*.png", DPI:=144)

Document Loading Method Change

// PdfiumViewer
PdfDocument.Load(path)

// IronPDF
PdfDocument.FromFile(path)

// PdfiumViewer
PdfDocument.Load(path)

// IronPDF
PdfDocument.FromFile(path)

' PdfiumViewer
PdfDocument.Load(path)

' IronPDF
PdfDocument.FromFile(path)

Save Method Change

// PdfiumViewer (takes a Stream)
document.Save(stream)

// IronPDF (takes a path)
pdf.SaveAs(path)

// PdfiumViewer (takes a Stream)
document.Save(stream)

// IronPDF (takes a path)
pdf.SaveAs(path)

' PdfiumViewer (takes a Stream)
document.Save(stream)

' IronPDF (takes a path)
pdf.SaveAs(path)

Disposal Pattern Simplification

// PdfiumViewer: explicit disposal of document and the rendered Image
using (var document = PdfDocument.Load(path))
using (var bitmap = document.Render(0, 1024, 768, 96, 96, PdfRenderFlags.None))
{
    bitmap.Save("output.png");
}

// IronPDF: Simplified
var pdf = PdfDocument.FromFile(path);
pdf.RasterizeToImageFiles("output.png");

// PdfiumViewer: explicit disposal of document and the rendered Image
using (var document = PdfDocument.Load(path))
using (var bitmap = document.Render(0, 1024, 768, 96, 96, PdfRenderFlags.None))
{
    bitmap.Save("output.png");
}

// IronPDF: Simplified
var pdf = PdfDocument.FromFile(path);
pdf.RasterizeToImageFiles("output.png");

Imports PdfiumViewer

' PdfiumViewer: explicit disposal of document and the rendered Image
Using document = PdfDocument.Load(path)
    Using bitmap = document.Render(0, 1024, 768, 96, 96, PdfRenderFlags.None)
        bitmap.Save("output.png")
    End Using
End Using

' IronPDF: Simplified
Dim pdf = PdfDocument.FromFile(path)
pdf.RasterizeToImageFiles("output.png")

Platform-Specific Code Removal

// PDFium wrapper: required platform detection / RID-specific binaries
#if WIN64
    // Load x64 pdfium.dll
#else
    // Load x86 pdfium.dll
#endif

// IronPDF: Remove all platform-specific code
// Just use the API directly

// PDFium wrapper: required platform detection / RID-specific binaries
#if WIN64
    // Load x64 pdfium.dll
#else
    // Load x86 pdfium.dll
#endif

// IronPDF: Remove all platform-specific code
// Just use the API directly

Pre-Migration

• Identify which PDFium wrapper is in use (PdfiumViewer / PdfiumViewer.Updated / PDFiumCore / Pdfium.Net.SDK)
• Document current rendering dimensions / DPI / scales used
• List native binary locations in project (per RID)
• Check for platform-specific loading code
• Identify PDF creation needs (currently using separate tools?)
• Review disposal patterns for conversion
• Obtain IronPDF license key

Package Changes

• Remove the PDFium wrapper NuGet package(s): PdfiumViewer, PdfiumViewer.Updated, PDFiumCore, or Pdfium.Net.SDK
• Delete native pdfium.dll / .so / .dylib binaries from x86/, x64/, runtimes/ folders
• Remove platform-specific conditional compilation
• Update .csproj to remove native binary references
• Install IronPdf NuGet package: dotnet add package IronPdf

Code Changes

• Add license key configuration at startup
• Replace PdfDocument.Load() with PdfDocument.FromFile()
• Replace document.Save() with pdf.SaveAs()
• Replace document.GetPdfText(i) loops with pdf.ExtractAllText()
• Convert scale factors to DPI values (DPI = 72 × scale)
• Simplify disposal patterns (remove nested using statements)
• Remove platform-specific code

Post-Migration

• Test rendering output quality
• Compare text extraction results
• Test cross-platform deployment
• Add new capabilities (HTML to PDF, merging, watermarks, security)
• Update documentation