LibrePDF/OpenPDF
OpenPDF
OpenPDF 是一个 Java 库和文档处理器，用于创建、编辑、渲染和加密 PDF 文档。它充当一个工具包，用于从零生成新文件、修改现有文档结构以及提取文本内容。
该项目包含一个专用引擎，通过解析标记并应用样式，将 HTML 和 CSS 内容转换为 PDF 文档。它还提供了一个渲染引擎，用于将 PDF 页面转换为图像格式以生成缩略图和预览，以及一个用于通过文档加密保护内容的安全实用程序。
该库支持添加图形、表格和多页 TIFF 图像。它通过支持多字节字符、双向文本和非拉丁脚本来处理复杂的排版。
该软件利用跨平台 Java 运行时，并包含在 Android 环境中启用文档处理的包。
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.
