Introduction

Meziantou.Framework.Pdf creates, reads, modifies, renders and signs PDF documents in .NET. It is written entirely in C# from the PDF 2.0 specification (ISO 32000-2): it has no native dependency, so it runs the same way on Windows, Linux and macOS, and in trimmed and NativeAOT applications.

What you can do with it

• Create documents: pages of any size, shapes, colors, text with the standard fonts or with embedded TrueType and OpenType fonts, images, gradients, patterns and transparency. See Creating documents.
• Describe and organize them: the title, the author and the XMP metadata, bookmarks, links and attached files. See Metadata and navigation.
• Read and modify existing documents: open files from any producer, repair files whose structure is damaged, extract the text, add content to the pages, and append changes without rewriting the original file. See Reading and modifying.
• Render pages to images: thumbnails and previews, with the embedded fonts, every image format and color space of PDF, shadings, patterns and transparency. See Rendering.
• Protect documents: encrypt them with passwords (RC4 and AES up to 256 bits), sign them with PAdES signatures and time stamps, and verify their signatures. See Security.
• Write accessible and archival documents: Tagged PDF, PDF/UA-1 and PDF/UA-2, PDF/A-1 to PDF/A-4. See Accessibility and archiving.
• Go below the API: every object of a document (dictionaries, arrays, streams) can be read and changed, for what the high-level API does not cover. See The object model.

Principles

• Real files are damaged. The reader accepts what PDF viewers accept, and rebuilds the structure of a file whose cross-reference information is wrong. PdfDocument.IsRepaired tells you when it did.
• Hostile files are bounded. Everything a file can make grow (the decoded streams, the nesting of objects, the work of a page that is rendered) has a limit. A file takes time and memory in proportion to its size.
• Errors are explicit. A file that is not a PDF document, a feature the library does not support, an exceeded limit and a wrong password each throw a distinct exception. See Errors and limits.
• Reproducible output. A save depends only on the document and the options: the library never writes the current date, a random value or its own version unless you ask it to. Only encryption adds random keys.
• Changes are kept apart from the original. An incremental save appends the changes to the original file and leaves its bytes untouched, so its signatures stay valid.

Namespaces

The library uses Meziantou.Framework.Imaging for the images (decoding, color profiles, the rendered pages) and Meziantou.Framework.Fonts for the fonts it embeds; both are installed with the package.

Next steps

• Getting started: install the package, create a document, read it and render it.
• Creating documents: pages, coordinates and the content builder.
• Limitations: what the library does not do.