TinyPdf C#

📖 Read the Deep-Dive: I built a minimal zero-dependency PDF library for C# because I hate bloat.

A minimal PDF creation library for .NET 10, ported from the original tinypdf by Lulzx.

Features

• 1041 lines of code
• Zero external dependencies
• Text rendering (Helvetica, Times, Courier) with alignment support
• Clickable links with optional underlining
• Shapes (Rectangles, Lines, Circles, Wedges)
• JPEG images
• Optional Flate (deflate) compression for PDF streams
• Markdown to PDF conversion
• Multiple pages with custom sizes

Supported framework

This project targets .NET 10.

Installation

Install the package via the .NET CLI:

dotnet add package TinyPdf

Alternatively, you can add the TinyPdf.csproj to your solution and reference it from your project:

dotnet add reference ../src/TinyPdf/TinyPdf.csproj

Usage

Simple PDF

using TinyPdf;

var builder = TinyPdfCreate.Create();
// disable compression if you need uncompressed streams
// builder.Compress = false;

builder.Page(ctx => {
    ctx.Text("Hello World", 50, 700, 24);
    ctx.Rect(50, 650, 100, 20, "#FF0000");
});

byte[] pdf = builder.Build();
File.WriteAllBytes("output.pdf", pdf);

Markdown to PDF

using TinyPdf;

// disable compression via options
var options = new TinyPdfCreate.MarkdownOptions(Compress: false);
string md = "# Header\n\nThis is a paragraph.\n\n- List item";
byte[] pdf = TinyPdfCreate.Markdown(md, options);
File.WriteAllBytes("markdown.pdf", pdf);

Advanced Page Options

builder.Page(842, 595, ctx => { // A4 Landscape
    ctx.Line(0, 0, 842, 595, "#0000FF", 2);
});

Charts and Shapes

builder.Page(ctx => {
    // ctx.Circle(cx, cy, radius, fill, stroke, lineWidth)
    ctx.Circle(100, 700, 50, "#3498db");

    // ctx.Wedge(cx, cy, radius, startAngle, endAngle, fill, stroke, lineWidth)
    ctx.Wedge(300, 700, 50, 0, 90, "#e74c3c", "#000000", 2);
});

Clickable Links

builder.Page(ctx => {
    ctx.Text("Visit our website", 50, 700, 12);
    // Link(url, x, y, width, height, options)
    ctx.Link("https://github.com/ian-cowley/tinypdf-csharp", 50, 700, 100, 12, new TinyPdfCreate.LinkOptions(Underline: "#2563eb"));
});

Running tests

From the repository root run:

dotnet test

Benchmarks

To run the high-concurrency performance tests (1000 iterations per example):

dotnet run --project benchmarks/PerformanceTests/PerformanceTests.csproj

Alternatively, to run the BenchmarkDotNet suite:

dotnet run -p benchmarks/TinyPdf.Benchmarks

Performance Results

The following results were obtained by generating 1000 PDFs for each example in parallel:

Example	Iterations	Total Time (ms)	Avg Time (ms)	Complexity
Invoice	1000	270.48	0.2705	Methods: ~320
Letter	1000	146.33	0.1463	Markdown: ~60 lines
PieChart	1000	40.10	0.0401	Methods: ~20
Receipt	1000	35.31	0.0353	Methods: ~18
Report	1000	44.86	0.0449	Methods: ~56
Resume	1000	99.03	0.0990	Markdown: ~100 lines

Publishing (Maintainers)

To release a new version to NuGet and GitHub:

1. Open PowerShell in the repository root.
2. Run: ./release.ps1
3. Follow the prompts for the commit message.

The script will automatically increment the patch version, commit, push, and create a GitHub tag, which triggers the CI/CD workflow.

Notes

This C# port preserves the core logic of the original TypeScript library (font width tables and PDF object serialization) so generated PDFs are compatible in structure. The library is intentionally small and dependency-free to keep it easy to embed in small projects.

By default output streams are compressed (FlateDecode) — set builder.Compress = false or pass new TinyPdfCreate.MarkdownOptions(Compress: false) to TinyPdfCreate.Markdown to disable compression.

Security: do not commit secrets or sensitive configuration to this repository. Use dotnet user-secrets or environment variables for local development.