MIGRATION GUIDES

How to Migrate from GdPicture.NET SDK to IronPDF in C#

Published:January 25, 2026

Migrating from GdPicture.NET SDK to IronPDF offers .NET developers a focused, streamlined approach to PDF generation. This guide provides a comprehensive, step-by-step migration path that replaces complex document imaging SDK patterns with modern, PDF-specific APIs designed for contemporary .NET development.

Why Migrate from GdPicture.NET SDK to IronPDF

The GdPicture.NET SDK Challenges

GdPicture.NET SDK (now rebranded as Nutrient) is a comprehensive document imaging SDK with several challenges for PDF-focused development:

Overkill for PDF-Only Projects: GdPicture.NET SDK is a full document imaging suite including OCR, barcode recognition, scanning, and image processing. If you only need PDF functionality, you're paying for features you'll never use.
Complex Licensing: Multiple product tiers (GdPicture.NET 14, GdPicture.API, Ultimate, Professional) with confusing SKU combinations and annual subscription requirements.
Enterprise Pricing: License costs start at $2,999 for the PDF plugin alone, scaling to $10,000+ for the Ultimate edition. Per-developer licensing adds significant overhead for growing teams.
Steep Learning Curve: The API is designed around document imaging concepts, not modern .NET patterns. Methods like LicenseManager.RegisterKEY(), GdPictureStatus enum checking, and 1-indexed pages feel dated compared to contemporary C# conventions.
Status Code Pattern: Every operation returns a GdPictureStatus enum that must be checked—no exceptions thrown on errors, making error handling verbose and repetitive.
Manual Resource Management: Requires explicit Dispose() or Release() calls. The SDK doesn't follow standard .NET disposal patterns cleanly.
Version Lock-in: The namespace GdPicture14 includes the version number, making major version upgrades require namespace changes throughout your entire codebase.
Rebranding Confusion: The recent rebrand to "Nutrient" creates documentation fragmentation between gdpicture.com and nutrient.io, complicating support and learning.

GdPicture.NET SDK vs IronPDF Comparison

Aspect	GdPicture.NET SDK	IronPDF
Focus	Document imaging suite (overkill for PDF)	PDF-specific library
Pricing	$2,999-$10,000+ enterprise tier	Competitive, scales with business
API Style	Status codes, manual management	Exceptions, IDisposable, modern .NET
Learning Curve	Steep (imaging SDK concepts)	Simple (HTML/CSS familiar)
HTML Rendering	Basic, internal engine	Latest Chromium with CSS3/JS
Page Indexing	1-indexed	0-indexed (standard .NET)
Thread Safety	Manual synchronization required	Thread-safe by design
Namespace	Version-specific (`GdPicture14`)	Stable (`IronPdf`)

For teams planning .NET 10 and C# 14 adoption through 2025 and 2026, IronPDF provides a future-proof foundation that aligns with modern .NET patterns and conventions.

Migration Complexity Assessment

Estimated Effort by Feature

Feature	Migration Complexity
HTML to PDF	Low
URL to PDF	Low
Merge PDFs	Low
Split PDFs	Low
Watermarks	Low
Text Extraction	Low
Password Protection	Medium
Form Fields	Medium
Digital Signatures	Medium-High
OCR	High
Barcode Recognition	N/A

Migration Decision Matrix

Your Situation	Recommendation
PDF-only operations	Migrate—significant simplification and cost savings
Heavy OCR usage	Consider IronOCR as companion product
Barcode/scanning needs	Keep GdPicture.NET SDK for those features, use IronPDF for PDF
Full document imaging	Evaluate if you actually use all features

Before You Start

Prerequisites

.NET Version: IronPDF supports .NET Framework 4.6.2+ and .NET Core 2.0+ / .NET 5/6/7/8/9+
License Key: Obtain your IronPDF license key from ironpdf.com
Backup: Create a branch for migration work

Identify All GdPicture.NET SDK Usage

# Find all GdPicture.NET SDK references in your codebase
grep -r "GdPicture14\|GdPicturePDF\|GdPictureDocumentConverter\|GdPictureStatus\|LicenseManager\.RegisterKEY" --include="*.cs" .

# Find all GdPicture package references
grep -r "GdPicture" --include="*.csproj" .

# Find all GdPicture.NET SDK references in your codebase
grep -r "GdPicture14\|GdPicturePDF\|GdPictureDocumentConverter\|GdPictureStatus\|LicenseManager\.RegisterKEY" --include="*.cs" .

# Find all GdPicture package references
grep -r "GdPicture" --include="*.csproj" .

SHELL

NuGet Package Changes

# Remove GdPicture.NET SDK packages
dotnet remove package GdPicture.NET.14
dotnet remove package GdPicture.NET.14.API
dotnet remove package GdPicture
dotnet remove package GdPicture.API

# Install IronPDF
dotnet add package IronPdf

# Remove GdPicture.NET SDK packages
dotnet remove package GdPicture.NET.14
dotnet remove package GdPicture.NET.14.API
dotnet remove package GdPicture
dotnet remove package GdPicture.API

# Install IronPDF
dotnet add package IronPdf

SHELL

Quick Start Migration

Step 1: Update License Configuration

Before (GdPicture.NET SDK):

// Must be called before any GdPicture.NET SDK operations
LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY");

// Must be called before any GdPicture.NET SDK operations
LicenseManager.RegisterKEY("YOUR-GDPICTURE-LICENSE-KEY");

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After (IronPDF):

// Set once at application startup
IronPdf.License.LicenseKey = "YOUR-IRONPDF-LICENSE-KEY";

// Or in appsettings.json:
// { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }

// Set once at application startup
IronPdf.License.LicenseKey = "YOUR-IRONPDF-LICENSE-KEY";

// Or in appsettings.json:
// { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }

' Set once at application startup
IronPdf.License.LicenseKey = "YOUR-IRONPDF-LICENSE-KEY"

' Or in appsettings.json:
' { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }

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Step 2: Update Namespace Imports

// Before (GdPicture.NET SDK)
using GdPicture14;

// After (IronPDF)
using IronPdf;
using IronPdf.Editing;

// Before (GdPicture.NET SDK)
using GdPicture14;

// After (IronPDF)
using IronPdf;
using IronPdf.Editing;

Imports IronPdf
Imports IronPdf.Editing

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Step 3: Basic Conversion Pattern

The most significant change in the GdPicture.NET SDK migration is eliminating the verbose status-checking pattern:

Before (GdPicture.NET SDK):

using GdPicture14;

LicenseManager.RegisterKEY("LICENSE-KEY");

using (GdPictureDocumentConverter converter = new GdPictureDocumentConverter())
{
    GdPictureStatus status = converter.LoadFromHTMLString("<h1>Hello World</h1>");

    if (status == GdPictureStatus.OK)
    {
        status = converter.SaveAsPDF("output.pdf");

        if (status != GdPictureStatus.OK)
        {
            Console.WriteLine($"Error: {status}");
        }
    }
    else
    {
        Console.WriteLine($"Load error: {status}");
    }
}

using GdPicture14;

LicenseManager.RegisterKEY("LICENSE-KEY");

using (GdPictureDocumentConverter converter = new GdPictureDocumentConverter())
{
    GdPictureStatus status = converter.LoadFromHTMLString("<h1>Hello World</h1>");

    if (status == GdPictureStatus.OK)
    {
        status = converter.SaveAsPDF("output.pdf");

        if (status != GdPictureStatus.OK)
        {
            Console.WriteLine($"Error: {status}");
        }
    }
    else
    {
        Console.WriteLine($"Load error: {status}");
    }
}

Imports GdPicture14

LicenseManager.RegisterKEY("LICENSE-KEY")

Using converter As New GdPictureDocumentConverter()
    Dim status As GdPictureStatus = converter.LoadFromHTMLString("<h1>Hello World</h1>")

    If status = GdPictureStatus.OK Then
        status = converter.SaveAsPDF("output.pdf")

        If status <> GdPictureStatus.OK Then
            Console.WriteLine($"Error: {status}")
        End If
    Else
        Console.WriteLine($"Load error: {status}")
    End If
End Using

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After (IronPDF):

using IronPdf;

IronPdf.License.LicenseKey = "LICENSE-KEY";

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
pdf.SaveAs("output.pdf");

using IronPdf;

IronPdf.License.LicenseKey = "LICENSE-KEY";

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
pdf.SaveAs("output.pdf");

Imports IronPdf

IronPdf.License.LicenseKey = "LICENSE-KEY"

Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>")
pdf.SaveAs("output.pdf")

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Key Differences:

No status checking—exceptions on errors
No explicit disposal required for renderer
Modern fluent API
Chromium-based rendering for better HTML/CSS support

Complete API Reference

Namespace Mapping

GdPicture.NET SDK	IronPDF
`GdPicture14`	`IronPdf`
`GdPicture14.PDF`	`IronPdf`
`GdPicture14.Imaging`	N/A (not needed)

Core Class Mapping

GdPicture.NET SDK	IronPDF	Description
`GdPicturePDF`	`PdfDocument`	Main PDF document class
`GdPictureDocumentConverter`	`ChromePdfRenderer`	HTML/URL to PDF conversion
`LicenseManager`	`IronPdf.License`	License management
`GdPictureStatus`	Exceptions	Error handling

Document Loading Methods

GdPicture.NET SDK	IronPDF
`pdf.LoadFromFile(path, loadInMemory)`	`PdfDocument.FromFile(path)`
`pdf.LoadFromFile(path, password, loadInMemory)`	`PdfDocument.FromFile(path, password)`
`converter.LoadFromHTMLString(html)`	`renderer.RenderHtmlAsPdf(html)`
`converter.LoadFromURL(url)`	`renderer.RenderUrlAsPdf(url)`

Page Operations

GdPicture.NET SDK	IronPDF
`pdf.GetPageCount()`	`pdf.PageCount`
`pdf.SelectPage(pageNo)`	`pdf.Pages[index]`
`pdf.GetPageWidth()`	`pdf.Pages[i].Width`
`pdf.GetPageHeight()`	`pdf.Pages[i].Height`

Merge and Split Operations

GdPicture.NET SDK	IronPDF
`pdf1.MergePages(pdf2)`	`PdfDocument.Merge(pdf1, pdf2)`
`pdf.ExtractPages(start, end)`	`pdf.CopyPages(indices)`

Watermark Operations

GdPicture.NET SDK	IronPDF
`pdf.DrawText(...)` loop	`pdf.ApplyWatermark(html)`
`pdf.SetTextColor(color)`	CSS styling
`pdf.SetTextSize(size)`	CSS styling

Code Migration Examples

Example 1: HTML to PDF Conversion

Before (GdPicture.NET SDK):

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;

class Program
{
    static void Main()
    {
        using (GdPictureDocumentConverter converter = new GdPictureDocumentConverter())
        {
            string htmlContent = "<html><body><h1>Hello World</h1></body></html>";
            GdPictureStatus status = converter.LoadFromHTMLString(htmlContent);

            if (status == GdPictureStatus.OK)
            {
                converter.SaveAsPDF("output.pdf");
            }
        }
    }
}

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;

class Program
{
    static void Main()
    {
        using (GdPictureDocumentConverter converter = new GdPictureDocumentConverter())
        {
            string htmlContent = "<html><body><h1>Hello World</h1></body></html>";
            GdPictureStatus status = converter.LoadFromHTMLString(htmlContent);

            if (status == GdPictureStatus.OK)
            {
                converter.SaveAsPDF("output.pdf");
            }
        }
    }
}

Imports GdPicture14
Imports System

Class Program
    Shared Sub Main()
        Using converter As New GdPictureDocumentConverter()
            Dim htmlContent As String = "<html><body><h1>Hello World</h1></body></html>"
            Dim status As GdPictureStatus = converter.LoadFromHTMLString(htmlContent)

            If status = GdPictureStatus.OK Then
                converter.SaveAsPDF("output.pdf")
            End If
        End Using
    End Sub
End Class

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After (IronPDF):

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

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        string htmlContent = "<html><body><h1>Hello World</h1></body></html>";
        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");
    }
}

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

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        string htmlContent = "<html><body><h1>Hello World</h1></body></html>";
        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");
    }
}

Imports IronPdf
Imports System

Class Program
    Shared Sub Main()
        Dim renderer = New ChromePdfRenderer()
        Dim htmlContent As String = "<html><body><h1>Hello World</h1></body></html>"
        Dim pdf = renderer.RenderHtmlAsPdf(htmlContent)
        pdf.SaveAs("output.pdf")
    End Sub
End Class

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IronPDF's ChromePdfRenderer uses a modern Chromium engine for accurate HTML/CSS rendering, eliminating the need for status code checking. For more HTML rendering options, see the HTML to PDF documentation.

Example 2: Merge Multiple PDFs

Before (GdPicture.NET SDK):

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;

class Program
{
    static void Main()
    {
        using (GdPicturePDF pdf1 = new GdPicturePDF())
        using (GdPicturePDF pdf2 = new GdPicturePDF())
        {
            pdf1.LoadFromFile("document1.pdf", false);
            pdf2.LoadFromFile("document2.pdf", false);

            pdf1.MergePages(pdf2);
            pdf1.SaveToFile("merged.pdf");
        }
    }
}

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;

class Program
{
    static void Main()
    {
        using (GdPicturePDF pdf1 = new GdPicturePDF())
        using (GdPicturePDF pdf2 = new GdPicturePDF())
        {
            pdf1.LoadFromFile("document1.pdf", false);
            pdf2.LoadFromFile("document2.pdf", false);

            pdf1.MergePages(pdf2);
            pdf1.SaveToFile("merged.pdf");
        }
    }
}

Imports GdPicture14
Imports System

Class Program
    Shared Sub Main()
        Using pdf1 As New GdPicturePDF(), pdf2 As New GdPicturePDF()
            pdf1.LoadFromFile("document1.pdf", False)
            pdf2.LoadFromFile("document2.pdf", False)

            pdf1.MergePages(pdf2)
            pdf1.SaveToFile("merged.pdf")
        End Using
    End Sub
End Class

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After (IronPDF):

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

class Program
{
    static void Main()
    {
        var pdf1 = PdfDocument.FromFile("document1.pdf");
        var pdf2 = PdfDocument.FromFile("document2.pdf");

        var merged = PdfDocument.Merge(new List<PdfDocument> { pdf1, pdf2 });
        merged.SaveAs("merged.pdf");
    }
}

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

class Program
{
    static void Main()
    {
        var pdf1 = PdfDocument.FromFile("document1.pdf");
        var pdf2 = PdfDocument.FromFile("document2.pdf");

        var merged = PdfDocument.Merge(new List<PdfDocument> { pdf1, pdf2 });
        merged.SaveAs("merged.pdf");
    }
}

Imports IronPdf
Imports System.Collections.Generic

Class Program
    Shared Sub Main()
        Dim pdf1 = PdfDocument.FromFile("document1.pdf")
        Dim pdf2 = PdfDocument.FromFile("document2.pdf")

        Dim merged = PdfDocument.Merge(New List(Of PdfDocument) From {pdf1, pdf2})
        merged.SaveAs("merged.pdf")
    End Sub
End Class

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IronPDF's static Merge method accepts a list of documents, making it easy to combine multiple PDFs in a single operation. Learn more about merging and splitting PDFs.

Example 3: Add Watermark to All Pages

Before (GdPicture.NET SDK):

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;
using System.Drawing;

class Program
{
    static void Main()
    {
        using (GdPicturePDF pdf = new GdPicturePDF())
        {
            pdf.LoadFromFile("input.pdf", false);

            for (int i = 1; i <= pdf.GetPageCount(); i++)
            {
                pdf.SelectPage(i);
                pdf.SetTextColor(Color.Red);
                pdf.SetTextSize(48);
                pdf.DrawText("CONFIDENTIAL", 200, 400);
            }

            pdf.SaveToFile("watermarked.pdf");
        }
    }
}

// NuGet: Install-Package GdPicture.NET
using GdPicture14;
using System;
using System.Drawing;

class Program
{
    static void Main()
    {
        using (GdPicturePDF pdf = new GdPicturePDF())
        {
            pdf.LoadFromFile("input.pdf", false);

            for (int i = 1; i <= pdf.GetPageCount(); i++)
            {
                pdf.SelectPage(i);
                pdf.SetTextColor(Color.Red);
                pdf.SetTextSize(48);
                pdf.DrawText("CONFIDENTIAL", 200, 400);
            }

            pdf.SaveToFile("watermarked.pdf");
        }
    }
}

Imports GdPicture14
Imports System
Imports System.Drawing

Module Program
    Sub Main()
        Using pdf As New GdPicturePDF()
            pdf.LoadFromFile("input.pdf", False)

            For i As Integer = 1 To pdf.GetPageCount()
                pdf.SelectPage(i)
                pdf.SetTextColor(Color.Red)
                pdf.SetTextSize(48)
                pdf.DrawText("CONFIDENTIAL", 200, 400)
            Next

            pdf.SaveToFile("watermarked.pdf")
        End Using
    End Sub
End Module

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After (IronPDF):

// NuGet: Install-Package IronPdf
using IronPdf;
using IronPdf.Editing;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");

        pdf.ApplyWatermark("<h1 style='color:red;'>CONFIDENTIAL</h1>", 50, VerticalAlignment.Middle, HorizontalAlignment.Center);

        pdf.SaveAs("watermarked.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using IronPdf.Editing;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");

        pdf.ApplyWatermark("<h1 style='color:red;'>CONFIDENTIAL</h1>", 50, VerticalAlignment.Middle, HorizontalAlignment.Center);

        pdf.SaveAs("watermarked.pdf");
    }
}

Imports IronPdf
Imports IronPdf.Editing

Class Program
    Shared Sub Main()
        Dim pdf = PdfDocument.FromFile("input.pdf")

        pdf.ApplyWatermark("<h1 style='color:red;'>CONFIDENTIAL</h1>", 50, VerticalAlignment.Middle, HorizontalAlignment.Center)

        pdf.SaveAs("watermarked.pdf")
    End Sub
End Class

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The GdPicture.NET SDK migration from coordinate-based text drawing to HTML-based watermarking simplifies code significantly. IronPDF's ApplyWatermark method uses HTML/CSS styling, eliminating the need for manual page iteration and coordinate calculations. See the complete watermarking documentation for additional options.

Example 4: Password Protection and Security

Before (GdPicture.NET SDK):

using GdPicture14;

class Program
{
    static void Main()
    {
        LicenseManager.RegisterKEY("LICENSE-KEY");

        using (GdPicturePDF pdf = new GdPicturePDF())
        {
            GdPictureStatus status = pdf.LoadFromFile("document.pdf", false);

            if (status != GdPictureStatus.OK) return;

            // Save with encryption - many boolean parameters
            status = pdf.SaveToFile(
                "protected.pdf",
                PdfEncryption.PdfEncryption256BitAES,
                "user123",      // User password
                "owner456",     // Owner password
                true,           // Can print
                false,          // Cannot copy
                false,          // Cannot modify
                false,          // Cannot add notes
                true,           // Can fill forms
                false,          // Cannot extract
                false,          // Cannot assemble
                true            // Can print high quality
            );
        }
    }
}

using GdPicture14;

class Program
{
    static void Main()
    {
        LicenseManager.RegisterKEY("LICENSE-KEY");

        using (GdPicturePDF pdf = new GdPicturePDF())
        {
            GdPictureStatus status = pdf.LoadFromFile("document.pdf", false);

            if (status != GdPictureStatus.OK) return;

            // Save with encryption - many boolean parameters
            status = pdf.SaveToFile(
                "protected.pdf",
                PdfEncryption.PdfEncryption256BitAES,
                "user123",      // User password
                "owner456",     // Owner password
                true,           // Can print
                false,          // Cannot copy
                false,          // Cannot modify
                false,          // Cannot add notes
                true,           // Can fill forms
                false,          // Cannot extract
                false,          // Cannot assemble
                true            // Can print high quality
            );
        }
    }
}

Imports GdPicture14

Class Program
    Shared Sub Main()
        LicenseManager.RegisterKEY("LICENSE-KEY")

        Using pdf As New GdPicturePDF()
            Dim status As GdPictureStatus = pdf.LoadFromFile("document.pdf", False)

            If status <> GdPictureStatus.OK Then Return

            ' Save with encryption - many boolean parameters
            status = pdf.SaveToFile(
                "protected.pdf",
                PdfEncryption.PdfEncryption256BitAES,
                "user123",      ' User password
                "owner456",     ' Owner password
                True,           ' Can print
                False,          ' Cannot copy
                False,          ' Cannot modify
                False,          ' Cannot add notes
                True,           ' Can fill forms
                False,          ' Cannot extract
                False,          ' Cannot assemble
                True            ' Can print high quality
            )
        End Using
    End Sub
End Class

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After (IronPDF):

using IronPdf;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("document.pdf");

        // Configure security settings with clear property names
        pdf.SecuritySettings.OwnerPassword = "owner456";
        pdf.SecuritySettings.UserPassword = "user123";

        // Set permissions
        pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights;
        pdf.SecuritySettings.AllowUserCopyPasteContent = false;
        pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit;
        pdf.SecuritySettings.AllowUserAnnotations = false;
        pdf.SecuritySettings.AllowUserFormData = true;

        pdf.SaveAs("protected.pdf");
    }
}

using IronPdf;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("document.pdf");

        // Configure security settings with clear property names
        pdf.SecuritySettings.OwnerPassword = "owner456";
        pdf.SecuritySettings.UserPassword = "user123";

        // Set permissions
        pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights;
        pdf.SecuritySettings.AllowUserCopyPasteContent = false;
        pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit;
        pdf.SecuritySettings.AllowUserAnnotations = false;
        pdf.SecuritySettings.AllowUserFormData = true;

        pdf.SaveAs("protected.pdf");
    }
}

Imports IronPdf

Class Program
    Shared Sub Main()
        Dim pdf = PdfDocument.FromFile("document.pdf")

        ' Configure security settings with clear property names
        pdf.SecuritySettings.OwnerPassword = "owner456"
        pdf.SecuritySettings.UserPassword = "user123"

        ' Set permissions
        pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights
        pdf.SecuritySettings.AllowUserCopyPasteContent = False
        pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit
        pdf.SecuritySettings.AllowUserAnnotations = False
        pdf.SecuritySettings.AllowUserFormData = True

        pdf.SaveAs("protected.pdf")
    End Sub
End Class

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IronPDF's SecuritySettings property provides named, self-documenting properties instead of positional boolean parameters.

Critical Migration Notes

Page Indexing Conversion

One of the most important changes in this GdPicture.NET SDK migration is the page indexing difference:

// GdPicture.NET SDK: 1-indexed pages
for (int i = 1; i <= pdf.GetPageCount(); i++)
{
    pdf.SelectPage(i);
    // process page
}

// IronPDF: 0-indexed pages (standard .NET)
for (int i = 0; i < pdf.PageCount; i++)
{
    var page = pdf.Pages[i];
    // process page
}

// GdPicture.NET SDK: 1-indexed pages
for (int i = 1; i <= pdf.GetPageCount(); i++)
{
    pdf.SelectPage(i);
    // process page
}

// IronPDF: 0-indexed pages (standard .NET)
for (int i = 0; i < pdf.PageCount; i++)
{
    var page = pdf.Pages[i];
    // process page
}

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Status Codes to Exceptions

Replace verbose status checking with standard try-catch:

// GdPicture.NET SDK
GdPictureStatus status = converter.LoadFromHTMLString(html);
if (status != GdPictureStatus.OK)
{
    Console.WriteLine($"Error: {status}");
    return;
}

// IronPDF
try
{
    var pdf = renderer.RenderHtmlAsPdf(html);
    pdf.SaveAs("output.pdf");
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
}

// GdPicture.NET SDK
GdPictureStatus status = converter.LoadFromHTMLString(html);
if (status != GdPictureStatus.OK)
{
    Console.WriteLine($"Error: {status}");
    return;
}

// IronPDF
try
{
    var pdf = renderer.RenderHtmlAsPdf(html);
    pdf.SaveAs("output.pdf");
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
}

' GdPicture.NET SDK
Dim status As GdPictureStatus = converter.LoadFromHTMLString(html)
If status <> GdPictureStatus.OK Then
    Console.WriteLine($"Error: {status}")
    Return
End If

' IronPDF
Try
    Dim pdf = renderer.RenderHtmlAsPdf(html)
    pdf.SaveAs("output.pdf")
Catch ex As Exception
    Console.WriteLine($"Error: {ex.Message}")
End Try

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Unit Conversion

GdPicture.NET SDK uses inches for margins; IronPDF uses millimeters:

// GdPicture.NET SDK: 0.5 inches margin
converter.HtmlSetMargins(0.5f, 0.5f, 0.5f, 0.5f);

// IronPDF: 0.5 inches = 12.7 mm
renderer.RenderingOptions.MarginTop = 12.7;
renderer.RenderingOptions.MarginBottom = 12.7;
renderer.RenderingOptions.MarginLeft = 12.7;
renderer.RenderingOptions.MarginRight = 12.7;

// GdPicture.NET SDK: 0.5 inches margin
converter.HtmlSetMargins(0.5f, 0.5f, 0.5f, 0.5f);

// IronPDF: 0.5 inches = 12.7 mm
renderer.RenderingOptions.MarginTop = 12.7;
renderer.RenderingOptions.MarginBottom = 12.7;
renderer.RenderingOptions.MarginLeft = 12.7;
renderer.RenderingOptions.MarginRight = 12.7;

' GdPicture.NET SDK: 0.5 inches margin
converter.HtmlSetMargins(0.5F, 0.5F, 0.5F, 0.5F)

' IronPDF: 0.5 inches = 12.7 mm
renderer.RenderingOptions.MarginTop = 12.7
renderer.RenderingOptions.MarginBottom = 12.7
renderer.RenderingOptions.MarginLeft = 12.7
renderer.RenderingOptions.MarginRight = 12.7

$vbLabelText $csharpLabel

Conversion formula: millimeters = inches × 25.4

Thread Safety

GdPicture.NET SDK requires manual synchronization for concurrent operations. IronPDF's ChromePdfRenderer is thread-safe by design, simplifying multi-threaded PDF generation.

Performance Considerations

Reuse ChromePdfRenderer

For optimal performance, reuse the renderer instance:

// GOOD - Reuse renderer (thread-safe)
public class PdfService
{
    private static readonly ChromePdfRenderer _renderer = new ChromePdfRenderer();

    public byte[] Generate(string html) => _renderer.RenderHtmlAsPdf(html).BinaryData;
}

// BAD - Creates new instance each time
public byte[] GenerateBad(string html)
{
    var renderer = new ChromePdfRenderer();  // Wasteful
    return renderer.RenderHtmlAsPdf(html).BinaryData;
}

// GOOD - Reuse renderer (thread-safe)
public class PdfService
{
    private static readonly ChromePdfRenderer _renderer = new ChromePdfRenderer();

    public byte[] Generate(string html) => _renderer.RenderHtmlAsPdf(html).BinaryData;
}

// BAD - Creates new instance each time
public byte[] GenerateBad(string html)
{
    var renderer = new ChromePdfRenderer();  // Wasteful
    return renderer.RenderHtmlAsPdf(html).BinaryData;
}

Imports System

Public Class PdfService
    Private Shared ReadOnly _renderer As New ChromePdfRenderer()

    Public Function Generate(html As String) As Byte()
        Return _renderer.RenderHtmlAsPdf(html).BinaryData
    End Function

    ' BAD - Creates new instance each time
    Public Function GenerateBad(html As String) As Byte()
        Dim renderer As New ChromePdfRenderer() ' Wasteful
        Return renderer.RenderHtmlAsPdf(html).BinaryData
    End Function
End Class

$vbLabelText $csharpLabel

Proper Resource Disposal

// Use using statements for automatic cleanup
using (var pdf = PdfDocument.FromFile("large.pdf"))
{
    string text = pdf.ExtractAllText();
}  // pdf is disposed automatically

// Use using statements for automatic cleanup
using (var pdf = PdfDocument.FromFile("large.pdf"))
{
    string text = pdf.ExtractAllText();
}  // pdf is disposed automatically

Imports PdfDocument

' Use Using blocks for automatic cleanup
Using pdf = PdfDocument.FromFile("large.pdf")
    Dim text As String = pdf.ExtractAllText()
End Using ' pdf is disposed automatically

$vbLabelText $csharpLabel

Migration Checklist

Pre-Migration

Inventory all GdPicture.NET SDK usage in codebase
Identify which features are actually used (PDF vs OCR vs barcode)
Determine if OCR/barcode features are needed (consider IronOCR/IronBarcode)
Review current licensing and compare to IronPDF pricing
Obtain IronPDF license key
Create migration branch in version control

Code Migration

Remove GdPicture.NET SDK NuGet packages: dotnet remove package GdPicture.NET
Install IronPdf NuGet package: dotnet add package IronPdf
Update namespace imports (GdPicture14 → IronPdf)
Replace LicenseManager.RegisterKEY() with IronPdf.License.LicenseKey
Convert status code checks to try-catch blocks
Update page indexing (1-indexed → 0-indexed)
Replace GdPicturePDF with PdfDocument
Replace GdPictureDocumentConverter with ChromePdfRenderer
Convert coordinate-based text to HTML stamping
Update unit conversions (inches → millimeters)

Testing

Unit test all PDF generation paths
Verify HTML rendering quality matches or exceeds
Test all security/encryption scenarios
Verify form filling functionality
Test merge/split operations
Validate watermark appearance
Performance benchmark critical paths

Post-Migration

Remove GdPicture.NET SDK license files/keys
Update documentation
Train team on IronPDF API patterns
Monitor production for any issues

Curtis Chau

Chat with engineering team now

Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

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How to Migrate from GdPicture.NET SDK to IronPDF in C#

Why Migrate from GdPicture.NET SDK to IronPDF

The GdPicture.NET SDK Challenges

GdPicture.NET SDK vs IronPDF Comparison

Migration Complexity Assessment

Estimated Effort by Feature

Migration Decision Matrix

Before You Start

Prerequisites

Identify All GdPicture.NET SDK Usage

NuGet Package Changes

Quick Start Migration

Step 1: Update License Configuration

Step 2: Update Namespace Imports

Step 3: Basic Conversion Pattern

Complete API Reference

Namespace Mapping

Core Class Mapping

Document Loading Methods

Page Operations

Merge and Split Operations

Watermark Operations

Code Migration Examples

Example 1: HTML to PDF Conversion

Example 2: Merge Multiple PDFs

Example 3: Add Watermark to All Pages

Example 4: Password Protection and Security

Critical Migration Notes

Page Indexing Conversion

Status Codes to Exceptions

Unit Conversion

Thread Safety

Performance Considerations

Reuse ChromePdfRenderer

Proper Resource Disposal

Migration Checklist

Pre-Migration

Code Migration

Testing

Post-Migration

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