📝 Text & Fonts
14 standard fonts + TrueType/OpenType embedding with subsetting. Unicode, CJK, Arabic, Cyrillic, emoji support.
View example →Helping you create standards-compliant, more accessible PDFs in .NET
Stop spending tens of thousands a year on PDF libraries. ObviousPDF enables .NET developers to produce standards-compliant, more accessible PDF documents — free for small teams, $100/yr for everyone else.
A zero-dependency .NET 8 library built directly from the ISO 32000 specification. Built-in PDF/UA accessibility, a fluent API, and 25+ features — all in a single assembly.
🚀 Zero Dependencies
♿ PDF/UA Accessible
📐 ISO 32000 Compliant
🔷 .NET 8+
⚡ Quick Start — Your First PDF in 4 Lines
Add a reference to ObviousPDF and start generating PDFs immediately. No configuration needed.
C# — Hello World
using ObviousPDF;
// Create a new PDF document
var doc = new PdfDocument();
// Add a US Letter page (612×792 points)
var page = doc.AddPage();
// Add text at 1 inch from left, 10 inches from bottom
page.AddText("Hello, World!", 72, 720);
// Save to disk
doc.Save("hello.pdf");
⚡ Easy Accessibility — The Recommended Pattern
One method call makes your entire document PDF/UA compliant. EnableAccessibility() auto-tags all text, images, and form fields — no structure tree required.
C# — Accessible Document (Easy Accessibility)
using ObviousPDF;
using ObviousPDF.Fonts;
var doc = new PdfDocument();
// One call — sets language, title, PDF/UA-1, auto-tagging
doc.EnableAccessibility("en-US", "Accessible Document");
var page = doc.AddPage();
// Decorative header — automatically treated as artifact
page.FillRectangle(0, 760, 612, 32,
new PdfDrawOptions { FillColor = PdfColor.FromRgb(0.15, 0.3, 0.6) });
// All AddText / AddTextBlock / AddImage calls are auto-tagged
page.AddText("Welcome to ObviousPDF", 72, 720,
new PdfTextOptions { EmbeddedFont = BundledFonts.SansBold, FontSize = 22 });
page.AddText("This document is fully accessible.", 72, 690,
new PdfTextOptions { FontSize = 14 });
page.AddText("• Tagged PDF for screen readers", 82, 660,
new PdfTextOptions { FontSize = 12 });
// Page number — automatically treated as artifact
page.AddText("Page 1", 285, 30,
new PdfTextOptions { FontSize = 10 });
doc.Save("accessible.pdf");
🚀 25+ Features, Zero Dependencies
Everything you need to generate professional PDFs — built directly from the ISO 32000 spec.
🎨 Vector Graphics
Lines, rectangles, circles, ellipses, polygons, Bézier paths. Dashes, fills, strokes, transparency.
View example →🖼️ Images
JPEG passthrough and PNG deconstruction with row filters, alpha channels, and aspect-preserving scaling.
View example →♿ Accessibility (PDF/UA)
Tagged PDF, structure trees, alt text, reading order, table headers, artifacts. 43+ automated checks.
View example →📊 Accessible Tables
Full table structure: THead/TBody/TFoot, header scope, ID/Headers associations, caption elements.
View example →📋 Interactive Forms
Text fields, checkboxes, dropdowns, list boxes, radio buttons, push buttons, signature fields.
View example →🔗 Links & Bookmarks
URI hyperlinks, tagged accessible links, document outlines for sidebar navigation.
View example →🔒 Encryption
AES-128 and AES-256 encryption with granular permissions — printing, copying, modifying, annotating.
View example →✍️ Digital Signatures
PKCS#7/CMS digital signatures with X.509 certificates. Reason, location, signer metadata.
View example →🗄️ PDF/A Archival
PDF/A-1b, PDF/A-2b, PDF/A-3b with OutputIntent, ICC colour profiles, and XMP metadata.
View example →🌈 Gradients & Patterns
Axial and radial gradients, tiling patterns for backgrounds, borders, and decorative fills.
View example →📐 Optional Content Layers
Show/hide content groups for blueprints, maps, annotations. Toggle layers in any PDF viewer.
View example →📊 Accessible Tables — Screen Reader Ready
Tables with proper header scope, ID associations, and caption elements.
C# — Accessible Table
// Build accessible table structure
var table = root.AddChild(StructureType.Table);
var caption = table.AddCaption();
// Header row with column scope
var thead = table.AddTableHead();
var hrow = thead.AddTableRow();
var thName = hrow.AddHeaderCell(
PdfTableScope.Column, id: "name");
var thAge = hrow.AddHeaderCell(
PdfTableScope.Column, id: "age");
// Data rows reference header IDs
var tbody = table.AddTableBody();
var row = tbody.AddTableRow();
var tdName = row.AddDataCell("name");
var tdAge = row.AddDataCell("age");
// Render tagged content
page.AddTaggedText(thName, "Name", 72, 700);
page.AddTaggedText(thAge, "Age", 200, 700);
page.AddTaggedText(tdName, "Alice", 72, 680);
page.AddTaggedText(tdAge, "30", 200, 680);
🎨 Vector Graphics — Shapes, Paths & Transparency
Full vector graphics API with fills, strokes, Bézier curves, and alpha blending.
C# — Vector Graphics
var page = doc.AddPage();
// Filled rectangle with styled border
page.DrawAndFillRectangle(100, 600, 200, 100,
new PdfDrawOptions {
FillColor = new PdfColor(0.9, 0.9, 1),
StrokeColor = new PdfColor(0, 0, 0.5),
LineWidth = 1.5
});
// Bézier curve path
page.BeginPath(new PdfDrawOptions {
FillColor = new PdfColor(0.3, 0.3, 0.8)
})
.MoveTo(300, 440)
.CurveTo(350, 520, 440, 480, 420, 440)
.ClosePath()
.FillAndStroke();
// Transparent overlapping circles
page.SaveGraphicsState();
page.SetAlpha(fillAlpha: 0.5);
page.FillCircle(140, 350, 40,
new PdfDrawOptions {
FillColor = new PdfColor(1, 0, 0) });
page.FillCircle(170, 350, 40,
new PdfDrawOptions {
FillColor = new PdfColor(0, 0, 1) });
page.RestoreGraphicsState();
♿ Built for Accessibility
ObviousPDF includes 43+ automated accessibility checks and makes it easy to create PDF/UA compliant documents that work with screen readers, magnifiers, and assistive technology.
🏗️ Structure Trees
Full ISO 32000 §14.7 structure tree with 40+ structure types — Document, Sect, P, H1–H6, Table, Figure, List, and more.
🔍 43+ Automated Checks
Built-in PdfAccessibilityChecker validates PDF/UA-1, PDF/UA-2, WCAG 2.2, and ISO 32000 requirements automatically.
🌐 International Support
Language tagging, pronunciation hints (/Phoneme), Ruby annotations for CJK, abbreviation expansion (/E).
📊 Table Semantics
Header scope (Row/Column/Both), ID/Headers associations, THead/TBody/TFoot, caption elements.
📥 Three Input Formats — One Accessible PDF
Define your document in JSON, XML, or CSV — ObviousPDF renders all three
to the same tagged, accessible PDF. Set accessible = true and every element is automatically
tagged for screen readers, with zero manual structure tree management.
📋 JSON Pipeline
Ideal for web APIs, JavaScript tooling, and LLM/AI-generated documents. "accessible": true enables full PDF/UA-1 compliance.
📄 XML Pipeline
Perfect for enterprise workflows, XSLT transforms, and schema validation. accessible="true" on the root element does the same.
📊 CSV Pipeline
Author PDFs in Excel or Google Sheets. The section-based format with accessible,true makes accessible PDFs from spreadsheets.
💰 Simple, Fair Licensing
Free for individuals and small teams. One flat annual fee for larger organizations.
Individual & Small Team
Free forever
- Individual developers
- Organizations with fewer than 10 employees
- Full feature set — no limitations
- All 25+ PDF features included
- PDF/UA accessibility tools
- Community support via GitHub
Enterprise
$100 /year
- Organizations with 10 or more employees
- Full feature set — no limitations
- All 25+ PDF features included
- PDF/UA accessibility tools
- Priority support
- Flat fee — unlimited developers
📥 Downloads
Get the library, documentation, and examples.
📦 ObviousPDF Assembly
The compiled ObviousPDF.dll — add a reference to your .NET 8+ project and start generating PDFs.
🤖 LLM Guide (Markdown)
Comprehensive guide for coding LLMs — patterns, API reference, accessibility requirements, and common pitfalls.
📖 API Reference
Complete API reference covering all classes, methods, properties, and enums in ObviousPDF.