wmjordan/pdfpatcher

PDFPatcher (PDF补丁丁) is a Windows desktop tool for editing and manipulating PDF files, written in C# on .NET Framework. The README is in Chinese. The tool covers a broad set of PDF operations without requiring Adobe Acrobat or any paid software. Its feature list includes: modifying document properties, page numbers, and internal links, removing copy and print restrictions from locked PDFs, rotating or resizing pages, splitting a large PDF into parts or merging multiple PDFs and images into one, exporting images from a PDF at full quality, converting PDF pages to image files, extracting or deleting specific pages and reordering them, and renaming PDF files based on their embedded metadata. A dedicated bookmark editor lets you view and edit the table-of-contents structure inside a PDF. You can change bookmark colors, styles, and target pages in bulk, run find-and-replace on bookmark text (including regex and XPath patterns), and automatically generate bookmarks from document headings. The editor includes a reading pane with right-to-left layout support for vertical Chinese text documents. There is also a document structure explorer that shows the internal tree of PDF objects, which you can edit directly or export to XML. Font replacement tools let you swap or embed fonts to fix garbled text when opening documents on devices without the original fonts installed, such as e-readers. An optional OCR feature reads text from image-based PDFs using Microsoft Office's document imaging component. The license is unusual: the software is free to use but comes with an AGPL-based license plus a conscience clause asking users to do one kind act after each time the software helps them, and asking developers who profit from the source code to donate a small share to those in need. It runs on Windows 7 and later with .NET Framework 4.0 through 4.8.