LibrePDF/OpenPDF
OpenPDF
OpenPDF is a Java library and document processor used for creating, editing, rendering, and encrypting PDF documents. It functions as a toolkit for generating new files from scratch, modifying existing document structures, and extracting text content.
The project includes a dedicated engine for transforming HTML and CSS content into PDF documents by parsing markup and applying styles. It also provides a rendering engine to convert PDF pages into image formats for thumbnails and previews, alongside a security utility for protecting content via document encryption.
The library supports the addition of graphics, tables, and multi-page TIFF images. It handles complex typography through support for multi-byte characters, bidirectional text, and non-Latin scripts.
The software leverages a cross-platform Java runtime and includes packages to enable document processing within Android environments.
Features
- PDF Document Generation - Generates new PDF documents from scratch using a programmatic Java interface.
- PDF Document Management - Offers a comprehensive toolkit for generating, editing, and manipulating PDF files and their structures.
- PDF Libraries - Provides a comprehensive Java library for creating, editing, rendering, and encrypting PDF documents.
- HTML to PDF Converters - Provides an engine to render HTML and CSS content into portable PDF documents.
- PDF Content Editing - Enables the modification of existing PDF files by altering text content and managing pages.
- PDF Tables and Graphics - Supports the embedding of images, vector graphics, and structured data tables to visualize information.
- PDF Text Extraction - Parses binary PDF files to extract raw text strings for processing and analysis.
- PDF Typography - Adds text using various styles and fonts to support complex glyphs and right-to-left scripts.
- HTML Layout Parsers - Features a layout parser that transforms HTML and CSS into a structured geometric box tree for PDF generation.
- PDF and HTML Content Extraction - Opens and parses existing PDF documents to extract content into standardized objects for modification.
- Compressed PDF Streams - Writes document content as sequential data streams using Flate or Brotli compression to minimize file size.
- Multi-Language Rendering - Provides support for rendering diverse scripts and multi-byte character sets to ensure correct visual display across different languages.
- PDF Internal Structure Access - Provides direct access to the internal PDF object model, including cross-reference tables and document trailers.
- Complex Script Renderers - Computes correct glyph positioning and reordering for accented letters, bidirectional text, and non-Latin scripts.
- PDF to Image Rendering - Transforms PDF page content into raster image formats for use in interfaces and files.
- PDF Security and Signing - Implements PDF security through password protection and encryption to restrict document access.
- PDF Encryptions and Decryptions - Implements encryption and decryption mechanisms to protect sensitive PDF files from unauthorized access.
- Document Encryption - Secures sensitive PDF content using encryption to restrict unauthorized access.
- Document Generation DSLs - Allows the creation of documents using a builder syntax and extension functions to define structure and content.
- Font Embedding - Embeds subsetted font data and glyph mappings to ensure consistent typography across different PDF viewers.
- Coordinate-Based Layouts - Provides a coordinate-based layout system to position text and graphics on a precise two-dimensional grid.
- Bidi Layout Engines - Implements bidirectional layout engines to correctly position right-to-left scripts within PDF documents.
- PDF Processing - Open-source fork for programmatic PDF creation.
