Mythosia.Documents.Pdf

Mythosia.Documents.Pdf

PDF document loader. Parses PDF files into DoclingDocument structured models via PdfPig. Provides font-size based heading detection, bullet/numbered list recognition, and spatial paragraph grouping. Supports encrypted PDFs, metadata extraction, and page number headers.

Installation

dotnet add package Mythosia.Documents.Pdf

Quick Start

using Mythosia.Documents.Pdf;

var loader = new PdfDocumentLoader();
IReadOnlyList<DoclingDocument> docs = await loader.LoadAsync("docs/manual.pdf");

string markdown = docs[0].ToMarkdown();

With RAG Pipeline

var service = new AnthropicService(apiKey, httpClient)
    .WithRag(rag => rag
        .AddDocuments(new PdfDocumentLoader(), "docs/manual.pdf")
    );

// Or auto-select loader by extension:
var service = new AnthropicService(apiKey, httpClient)
    .WithRag(rag => rag.AddDocument("docs/manual.pdf"));

Structured Extraction

The parser analyses font sizes and spatial layout to produce a structured DoclingDocument:

• Headings — text with font size exceeding the body font size (mode) by ≥15% is classified as heading level 1–3 based on size ratio.
• Lists — lines starting with bullet characters (•, -, *, etc.) or numbered patterns (1., a), iv.) are emitted as list items.
• Paragraphs — words are grouped into lines by Y-coordinate proximity. Consecutive body-text lines are merged into a single paragraph; vertical gaps larger than 1.4× line height trigger a paragraph break.
• Fallback — if GetWords() returns no results but raw page text exists, the text is preserved as a paragraph.

Parser Options

using Mythosia.Documents.Pdf;

var options = new PdfParserOptions
{
    Password = null,              // For encrypted PDFs
    IncludeMetadata = true,       // Extract title, author, page count
    IncludePageNumbers = false,   // Add page number headers
    NormalizeWhitespace = true,   // Collapse excessive whitespace (preserves newlines)
};

var loader = new PdfDocumentLoader(options: options);

Custom Parser

Implement IDocumentParser and pass it to the loader:

var loader = new PdfDocumentLoader(parser: new MyCustomPdfParser());

Related Packages

Package	Description
Mythosia.Documents.Abstractions	Core abstractions (DoclingDocument, IDocumentLoader)
Mythosia.Documents.Office	Word / Excel / PowerPoint loaders
Mythosia.AI.Rag	RAG pipeline