ToPdfNet 0.0.1

ToPdfNet

ToPdfNet is a pure managed .NET and C# HTML-to-PDF converter for single-file and report-oriented HTML. It converts HTML strings, files, and streams to PDF without Chromium, headless Chrome, wkhtmltopdf, CEF, System.Drawing, WPF, SkiaSharp, native binaries, or external browser processes.

The library is designed for invoices, tabular reports, statements, simple letters, and server-side PDF generation where deployment simplicity matters more than browser-perfect layout.

Install

dotnet add package ToPdfNet

Optional command-line tool:

dotnet tool install --global ToPdfNet.Cli

Library Usage

using ToPdfNet;

var pdf = ToPdf.FromHtml("""
<h1>Invoice INV-1001</h1>
<p><strong>Customer:</strong> Contoso Ltd</p>
<table>
  <tr><th>Description</th><th>Amount</th></tr>
  <tr><td>Managed PDF generation</td><td>$250.00</td></tr>
</table>
""");

File.WriteAllBytes("invoice.pdf", pdf);

Files and streams use the same API shape:

byte[] fromFile = ToPdf.FromHtmlFile("report.html");

await using var input = File.OpenRead("report.html");
byte[] fromStream = ToPdf.FromHtmlStream(input);

Rendering options control page size, margins, metadata, default font settings, and a CSS stylesheet string:

var options = new PdfRenderOptions
{
    Title = "Monthly Report",
    Author = "Reporting Service",
    PageSize = PdfPageSize.Letter,
    Margin = PdfMargin.FromInches(0.5),
    Stylesheet = "th { background-color: #eeeeee; } td, th { border: 1pt solid #cccccc; padding: 5pt; }"
};

byte[] pdf = ToPdf.FromHtmlFile("monthly-report.html", options);

CLI Usage

topdfnet samples/html/invoice.html -o invoice.pdf --title "Sample Invoice" --margin 0.6in

From the repository without installing the tool:

dotnet run --project src/ToPdfNet.Cli -- samples/html/invoice.html -o samples/pdf/invoice.pdf

Useful flags:

• --stylesheet <path> applies a CSS file.
• --page-size a4|letter|WIDTHxHEIGHT sets the page size.
• --margin <length> sets equal margins, such as 0.5in, 12mm, or 36pt.
• --title, --author, --subject, and --keywords set PDF metadata.

Samples

The samples/html folder contains examples from simple to dense:

• simple-letter.html
• invoice.html
• profile.html
• long-report.html
• operations-report.html

Generated PDFs are checked into samples/pdf so people can inspect output without building the project first.

How It Works

ToPdfNet parses HTML with HtmlAgilityPack, resolves a small CSS subset, and draws PDF pages with PDFsharp. It supports deterministic report structures: text, headings, paragraphs, simple blocks, lists, tables, borders, backgrounds, local images, and base64 data URI images.

It intentionally does not execute JavaScript, fetch remote network resources, or try to reproduce browser layout algorithms. For pixel-perfect webpage capture, use a browser-backed renderer in a separate application boundary.

Supported HTML And CSS

Supported:

• Text, headings, paragraphs, divisions, spans, and line breaks.
• Bold, italic, underline, basic font size, color, and alignment.
• Lists, tables, table headers, simple borders, padding, and backgrounds.
• Local images and data URI images supported by PDFsharp.
• Page size, margins, document metadata, inline styles, and optional stylesheet text.

Unsupported by design:

• JavaScript.
• Browser layout features such as flexbox, grid, animations, and media queries.
• Pixel-perfect webpage capture.
• Remote network asset loading.
• Native browser engines or platform-specific drawing stacks.

See docs/css-support.md and docs/limitations.md for details.

Repository Layout

src/ToPdfNet          Library package
src/ToPdfNet.Cli      dotnet tool package
tests/ToPdfNet.Tests  Focused behavior tests
samples/html          Example HTML inputs
samples/pdf           Generated sample PDFs
docs                  Public usage and support notes

Development

dotnet restore ToPdfNet.slnx
dotnet build ToPdfNet.slnx
dotnet test ToPdfNet.slnx
dotnet pack src/ToPdfNet/ToPdfNet.csproj -c Release
dotnet pack src/ToPdfNet.Cli/ToPdfNet.Cli.csproj -c Release

The GitHub workflows build, test, and pack on pull requests. NuGet publishing is handled by the release workflow when a v* tag is pushed or the workflow is run manually with a version.