HtmlToPdfCore (RoyceLark Corporations)

A robust, high-performance HTML to PDF rendering library for .NET 9 with AI/ML-powered and Soon .NET 10 with AI/ML-powered optimizations.

Features

Core Features

✅ HTML to PDF conversion with full CSS support
✅ JavaScript execution support
✅ Multiple page sizes (A0-A6, Letter, Legal, Tabloid, Ledger, Custom)
✅ Portrait and Landscape orientations
✅ Custom margins and page settings
✅ Header and footer support with page numbers
✅ URL to PDF conversion
✅ File-based rendering
✅ Custom CSS injection
✅ PDF metadata support

Advanced Features

✅ PDF merging and splitting
✅ Watermark support (text, position, opacity, rotation)
✅ PDF encryption with password protection
✅ Text extraction from PDFs
✅ Image compression and quality control
✅ Grayscale rendering
✅ Custom DPI settings

AI/ML Features

✅ AI-powered memory usage prediction
✅ Intelligent resource optimization
✅ Automatic performance tuning
✅ Memory leak prevention
✅ Content complexity analysis

Performance & Reliability

✅ Object pooling for memory efficiency
✅ Concurrent rendering with semaphore control
✅ Async/await throughout
✅ CancellationToken support
✅ Comprehensive error handling
✅ Structured logging with Microsoft.Extensions.Logging
✅ Thread-safe operations

Installation

dotnet add package RoyceLark.HtmlToPdfCore

Or via NuGet Package Manager:

Install-Package RoyceLark.HtmlToPdfCore

Quick Start

Simple Usage

using RoyceLark.HtmlToPdfCore;

// Create instance
var converter = HtmlToPdf.Create();

// Render HTML to PDF
var html = "<h1>Hello World!</h1><p>This is a PDF document.</p>";
var pdfBytes = await converter.RenderAsync(html);

// Save to file
await File.WriteAllBytesAsync("output.pdf", pdfBytes);

Fluent API

using RoyceLark.HtmlToPdfCore;
using RoyceLark.HtmlToPdfCore.Models;

var converter = HtmlToPdf.Create();

await converter
    .FromHtml("<h1>My Document</h1><p>Content here...</p>")
    .WithPageSize(PageSize.A4)
    .WithOrientation(PageOrientation.Portrait)
    .WithMargins(20, 20, 20, 20)
    .WithMetadata(m =>
    {
        m.Title = "My Document";
        m.Author = "Your Name";
    })
    .SaveAsync("output.pdf");

With Configuration

var html = "<h1>Configured Document</h1>";

var pdfBytes = await converter.RenderAsync(html, options =>
{
    options.PageSize = PageSize.Letter;
    options.Orientation = PageOrientation.Landscape;
    options.Margins = new PageMargins(15, 15, 15, 15);
    options.EnableJavaScript = true;
    options.PrintBackground = true;
    options.ImageQuality = 90;
    options.Dpi = 300;
    
    // Header with page numbers
    options.Footer = new HeaderFooterOptions
    {
        ShowPageNumbers = true,
        PageNumberFormat = "Page {page} of {total}",
        Alignment = TextAlignment.Center
    };
    
    // Metadata
    options.Metadata = new PdfMetadata
    {
        Title = "My Report",
        Author = "John Doe",
        Subject = "Monthly Report",
        Keywords = "report, monthly, analytics"
    };
});

Advanced Usage

Render from URL

var pdfBytes = await converter.RenderUrlAsync("https://example.com");

Render from File

var pdfBytes = await converter.RenderFileAsync("template.html");

Custom CSS Injection

var html = "<h1>Styled Document</h1>";

var pdfBytes = await converter.RenderAsync(html, options =>
{
    options.CustomCss = @"
        body { font-family: 'Arial', sans-serif; }
        h1 { color: #333; border-bottom: 2px solid #007bff; }
        p { line-height: 1.6; }
    ";
});

PDF Manipulation

Merge PDFs

var pdf1 = await converter.RenderAsync("<h1>Document 1</h1>");
var pdf2 = await converter.RenderAsync("<h1>Document 2</h1>");
var pdf3 = await converter.RenderAsync("<h1>Document 3</h1>");

var mergedPdf = await converter.MergeAsync(new[] { pdf1, pdf2, pdf3 });

Split PDF

var pdf = await converter.RenderAsync("<h1>Page 1</h1><div style='page-break-after: always;'></div><h1>Page 2</h1>");

// Split into individual pages
var pages = await converter.SplitAsync(pdf, new[] { 1, 2 });

Add Watermark

var pdf = await converter.RenderAsync("<h1>Confidential Document</h1>");

var watermarkedPdf = await converter.AddWatermarkAsync(pdf, "CONFIDENTIAL", options =>
{
    options.Opacity = 0.3f;
    options.FontSize = 72;
    options.Rotation = 45;
    options.Position = WatermarkPosition.Center;
    options.Color = "#FF0000";
});

Encrypt PDF

var pdf = await converter.RenderAsync("<h1>Secure Document</h1>");

var encryptedPdf = await converter.EncryptAsync(
    pdf,
    userPassword: "user123",
    ownerPassword: "admin456"
);

Extract Text

var pdf = await converter.RenderAsync("<h1>Hello World</h1><p>This is sample text.</p>");

var text = await converter.ExtractTextAsync(pdf);
Console.WriteLine(text);

Dependency Injection

ASP.NET Core Integration

using RoyceLark.HtmlToPdfCore.Extensions;

// In Program.cs or Startup.cs
builder.Services.AddHtmlToPdfCore(options =>
{
    options.EnableAIOptimization = true;
    options.MaxConcurrentRenders = Environment.ProcessorCount;
    options.DefaultRenderTimeout = 30000;
});

// In your controller or service
public class ReportController : ControllerBase
{
    private readonly IHtmlToPdfRenderer _renderer;
    
    public ReportController(IHtmlToPdfRenderer renderer)
    {
        _renderer = renderer;
    }
    
    [HttpGet("generate")]
    public async Task<IActionResult> GenerateReport()
    {
        var html = "<h1>Monthly Report</h1><p>Content...</p>";
        var pdf = await _renderer.RenderHtmlToPdfAsync(html);
        
        return File(pdf, "application/pdf", "report.pdf");
    }
}

Certificate Generation

using RoyceLark.HtmlToPdfCore.Extensions;


// In your controller or service
public class ReportController : ControllerBase
{
    private readonly IHtmlToPdfRenderer _renderer;
    
    public ReportController(IHtmlToPdfRenderer renderer)
    {
        _renderer = renderer;
    }
    
    [HttpGet("generate")]
    public async Task<IActionResult> GenerateReport()
    {
        var projectRoot = Directory.GetCurrentDirectory();
            var baseUrl = new Uri(projectRoot + Path.DirectorySeparatorChar).AbsoluteUri;

            var converter = HtmlToPdf.Create();
            var watermark = "";
            var pdf = await converter.RenderAsync(certificateHtml, options =>
            {
                // FitToPaperWidth equivalent - handled automatically by page size
                options.PageSize = PageSize.Legal;
                options.Orientation = PageOrientation.Portrait;// PaperOrientation
                options.MediaType = CssMediaType.Screen;
                //for css rendering
                options.BaseUrl = baseUrl;
                // Reduce font size by 20%
                options.FontScale = 0.8f;  // 80% of original

                // Increase margins for portrait mode
                options.Margins = new PageMargins(
                    top: 20,      // Increased
                    right: 30,    // Increased  
                    bottom: 20,   // Increased
                    left: 30      // Increased
                );

                options.FitToPaperWidth = true;
                options.PrintBackground = true;


                // Additional useful options
               // options.EnableJavaScript = true;
                options.Dpi = 96;
                options.ImageQuality = 100;
            });
            pdf = await converter.AddWatermarkAsync(pdf, "Draft", options =>
            {
                options.Position = WatermarkPosition.Center;  // MiddleCenter
                options.Opacity = 0.3f;  // 30% opacity
                options.FontSize = 72;
                options.Rotation = 45;
                options.Color = "#808080";
            });
            //Then add watermark
           pdf = await converter.AddWatermarkAsync(pdf, watermark, options =>
           {
               options.Position = WatermarkPosition.Center;
               options.Opacity = 0.3f;
           });

            return File(pdf, "application/pdf", "certificate.pdf");
    }
}

AI/ML Optimization

The library includes built-in AI/ML capabilities for performance optimization:

using RoyceLark.HtmlToPdfCore;
using Microsoft.Extensions.Logging;

var loggerFactory = LoggerFactory.Create(builder => 
    builder.AddConsole().SetMinimumLevel(LogLevel.Information));

var converter = HtmlToPdf.Create(loggerFactory);

// AI optimization is enabled by default
var html = "<h1>Complex Document</h1>" + string.Join("", 
    Enumerable.Range(1, 1000).Select(i => $"<p>Paragraph {i}</p>"));

var pdfBytes = await converter.RenderAsync(html, options =>
{
    options.EnableAIOptimization = true; // Enabled by default
});

// The AI will:
// - Predict memory usage
// - Optimize rendering strategy
// - Prevent memory leaks
// - Adjust compression levels
// - Determine optimal chunk sizes

Performance Best Practices

Reuse Instances: Create one HtmlToPdf instance and reuse it
Enable AI Optimization: Keep EnableAIOptimization enabled for best performance
Use Async Methods: Always use async/await for better scalability
Set Appropriate Timeouts: Configure timeouts based on document complexity
Compress Images: Enable image compression for smaller file sizes
Use Object Pooling: The library automatically uses object pooling for streams

Examples

Invoice Generation

var invoiceHtml = @"
<!DOCTYPE html>
<html>
<head>
    <style>
        body { font-family: Arial, sans-serif; }
        .header { text-align: center; color: #333; }
        .invoice-details { margin: 20px 0; }
        table { width: 100%; border-collapse: collapse; }
        th, td { border: 1px solid #ddd; padding: 8px; text-align: left; }
        th { background-color: #f2f2f2; }
        .total { font-weight: bold; font-size: 1.2em; }
    </style>
</head>
<body>
    <div class='header'>
        <h1>INVOICE</h1>
        <p>Invoice #12345</p>
    </div>
    <div class='invoice-details'>
        <p><strong>Date:</strong> 2024-12-08</p>
        <p><strong>Customer:</strong> John Doe</p>
    </div>
    <table>
        <thead>
            <tr>
                <th>Item</th>
                <th>Quantity</th>
                <th>Price</th>
                <th>Total</th>
            </tr>
        </thead>
        <tbody>
            <tr>
                <td>Product A</td>
                <td>2</td>
                <td>$50.00</td>
                <td>$100.00</td>
            </tr>
            <tr>
                <td>Product B</td>
                <td>1</td>
                <td>$75.00</td>
                <td>$75.00</td>
            </tr>
        </tbody>
        <tfoot>
            <tr class='total'>
                <td colspan='3'>Total</td>
                <td>$175.00</td>
            </tr>
        </tfoot>
    </table>
</body>
</html>";

await converter
    .FromHtml(invoiceHtml)
    .WithPageSize(PageSize.A4)
    .WithFooter("", showPageNumbers: true)
    .WithMetadata(m =>
    {
        m.Title = "Invoice #12345";
        m.Author = "Company Name";
    })
    .SaveAsync("invoice.pdf");

Certificate Generation

var certificateHtml = @"
<!DOCTYPE html>
<html>
<head>
    <style>
        body {
            font-family: 'Georgia', serif;
            text-align: center;
            padding: 50px;
        }
        h1 {
            font-size: 48px;
            color: #2c3e50;
            margin-bottom: 30px;
        }
        .recipient {
            font-size: 36px;
            color: #3498db;
            margin: 30px 0;
        }
        .description {
            font-size: 18px;
            margin: 20px 0;
        }
    </style>
</head>
<body>
    <h1>Certificate of Achievement</h1>
    <p class='description'>This is to certify that</p>
    <p class='recipient'>John Doe</p>
    <p class='description'>has successfully completed the course</p>
    <p class='recipient'>Advanced .NET Development</p>
    <p class='description'>Date: December 8, 2024</p>
</body>
</html>";

await converter
    .FromHtml(certificateHtml)
    .WithPageSize(PageSize.A4)
    .WithOrientation(PageOrientation.Landscape)
    .SaveAsync("certificate.pdf");

Error Handling

try
{
    var pdfBytes = await converter.RenderAsync(html);
}
catch (PdfRenderException ex)
{
    // Handle rendering errors
    Console.WriteLine($"Rendering failed: {ex.Message}");
    
    if (ex.InnerException != null)
    {
        Console.WriteLine($"Inner error: {ex.InnerException.Message}");
    }
}
catch (OperationCanceledException)
{
    // Handle cancellation
    Console.WriteLine("Operation was cancelled");
}

Requirements

.NET 9.0 soon .Net 10
Windows, Linux, or macOS

Dependencies

iText7 (9.0.4)
iText7.pdfhtml (6.3.0)
HtmlAgilityPack (1.11.61)
Microsoft.ML (3.0.1)
AngleSharp (1.1.2)
SixLabors.ImageSharp (3.1.5)

License

MIT License

Support

For issues, questions, or contributions, please visit: https://github.com/roycelark/RoyceLark.HtmlToPdfCore

Changelog

Version 1.0.0

Initial release
Full HTML to PDF rendering
AI/ML-powered optimizations
Comprehensive PDF manipulation
.NET 9 and soon .NET 10 support

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Acknowledgments

Built with:

iText7 for PDF generation
Microsoft.ML for AI capabilities
AngleSharp for HTML parsing

Name		Name	Last commit message	Last commit date
Latest commit History 2 Commits
AI		AI
Extensions		Extensions
Interfaces		Interfaces
Licensing		Licensing
Models		Models
Properties		Properties
Renderers		Renderers
Services		Services
.dockerignore		.dockerignore
.editorconfig		.editorconfig
.gitignore		.gitignore
ANTI-PIRACY.md		ANTI-PIRACY.md
CONTACT_INFO.md		CONTACT_INFO.md
COPYRIGHT.txt		COPYRIGHT.txt
COPYRIGHT_HEADER.txt		COPYRIGHT_HEADER.txt
GETTING_STARTED.md		GETTING_STARTED.md
HtmlToPdf.cs		HtmlToPdf.cs
HtmlToPdfCore.csproj		HtmlToPdfCore.csproj
HtmlToPdfCore.sln		HtmlToPdfCore.sln
LICENSE.txt		LICENSE.txt
README.md		README.md

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HtmlToPdfCore (RoyceLark Corporations)

Features

Core Features

Advanced Features

AI/ML Features

Performance & Reliability

Installation

Quick Start

Simple Usage

Fluent API

With Configuration

Advanced Usage

Render from URL

Render from File

Custom CSS Injection

PDF Manipulation

Merge PDFs

Split PDF

Add Watermark

Encrypt PDF

Extract Text

Dependency Injection

ASP.NET Core Integration

Certificate Generation

AI/ML Optimization

Performance Best Practices

Examples

Invoice Generation

Certificate Generation

Error Handling

Requirements

Dependencies

License

Support

Changelog

Version 1.0.0

Contributing

Acknowledgments

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