PdfRes 1.2.0

PdfRes

A production-ready, deterministic HTML-to-PDF generation library for .NET 8.
Pure managed code — no headless browser, no native binaries, no external process dependencies.

Features

Installation

dotnet add package PdfRes

Quick Start

// One-liner
var result = PdfGenerator.Default.Generate("<h1>Hello World</h1><p>Generated by PdfRes.</p>");
result.SaveToFile("output.pdf");

Configured Usage

using PdfRes;
using PdfRes.Configuration;

using var generator = PdfGenerator.CreateBuilder()
    .WithPageSize(PageSize.A4)
    .WithMargins(PageMargins.Normal)
    .WithTitle("Invoice #12345")
    .WithAuthor("Acme Corp")
    .WithScreenDpi(96)
    .WithMaxConcurrency(4)
    .WithSecurity(SecurityPolicy.Relaxed)
    .Build();

var result = await generator.GenerateAsync(htmlContent);

Console.WriteLine($"Pages   : {result.PageCount}");
Console.WriteLine($"Size    : {result.FileSizeBytes} bytes");
Console.WriteLine($"Total   : {result.TotalDuration.TotalMilliseconds:F1} ms");

await result.SaveToFileAsync("invoice.pdf");

Batch Generation

var htmlDocuments = new[] { html1, html2, html3 };
var results = await generator.GenerateBatchAsync(htmlDocuments);

foreach (var r in results)
    Console.WriteLine($"Pages: {r.PageCount}, Size: {r.FileSizeBytes} bytes");

Custom Options Per Call

var landscapeOptions = new PdfOptions
{
    PageSize    = PageSize.A4.Landscape(),
    Margins     = PageMargins.Narrow,
    Title       = "Report",
    Fonts       = new FontOptions { DefaultFontFamily = "Times-Roman", DefaultFontSizePt = 11 }
};

var result = await generator.GenerateAsync(html, landscapeOptions);

Supported HTML / CSS

Elements

div, p, h1–h6, span, strong, em, b, i, u, s, ul, ol, li, table, tr, td, th, thead, tbody, pre, code, blockquote, hr, br, a, section, article, header, footer

CSS Properties

color, background-color, font-family, font-size, font-weight, font-style, text-align, line-height, text-decoration, direction, white-space, opacity, margin, padding, border, width, height, min/max-width/height, display, page-break-before, page-break-after, page-break-inside

Selectors

Tag, .class, #id, tag.class, tag#id, *, multi-selector (,)

Architecture

HTML Input
   │
   ▼
[Security] HtmlSanitizer       — removes scripts, event handlers, enforces size limits
   │
   ▼
[Parsing]  HtmlParser          — lightweight HTML → DOM tree (no external deps)
           CssResolver         — cascade, specificity, inheritance, user-agent defaults
   │
   ▼
[Layout]   LayoutEngine        — deterministic CSS box model, text wrapping, table layout
           PageBreaker         — orphan-aware page splitting, page-break-* support
   │
   ▼
[Render]   PdfRenderer         — PDF 1.7 binary format, font embedding, coordinate transform
           PdfDocumentWriter   — low-level object/stream/xref writer
   │
   ▼
byte[] PDF

Security

PdfRes uses SecurityPolicy.Strict by default:

• ❌ No JavaScript execution
• ❌ No remote resource loading
• ❌ No <script>, <iframe>, <form>, <object> elements
• ❌ No event handler attributes (onclick, onload, …)
• ✅ Configurable maximum input size (default 5 MB)
• ✅ Maximum DOM nesting depth (default 100)

Performance Notes

• All pipeline stages are stateless — PdfGenerator is safely shared across threads
• CPU-bound rendering is offloaded to Task.Run to keep caller threads free
• ConcurrencyLimiter prevents unbounded parallelism in high-load scenarios
• MemoryStream pooling avoids large GC pressure on repeated calls

License

MIT © PdfRes Contributors