Unofficial fork of SumatraPDF.
Not affiliated with sumatrapdfreader.org.
This repository publishes source code for Sumatra PDF Plus, a Windows build derived from SumatraPDF.
Because SumatraPDF is licensed under GNU GPLv3, modified binaries must be accompanied by corresponding source under the same license. This repo satisfies that requirement.
- User guide (Chinese): readme.txt
- Upstream project: https://github.com/sumatrapdfreader/sumatrapdf
- License: COPYING (GPLv3) + AUTHORS
- Chinese EPUB/MOBI layout and TOC — improved mixed text/image layout; fixes for incorrect or broken table-of-contents navigation.
- Faster opening of large ebooks — loading performance for big EPUB/MOBI files.
- Session-restore crash fix — when “reopen files from last session” is enabled, launching by double-clicking a file no longer crashes.
- Offline dictionary lookup — double-click a word in the document; optional English–Chinese and Chinese dictionaries via a
dictfolder next to the exe. - Dark mode — light/dark theme toggle with UI polish (toolbar, word-lookup popup follows theme, etc.).
Product display name: Sumatra PDF Plus (kAppName in src/Version.h). The executable filename is still SumatraPDF.exe.
Requirements: Visual Studio 2022 build tools, Bun.
bun ./cmd/build.ts # debug → out/dbg64/SumatraPDF.exe
bun ./cmd/build-all.ts # release → out/rel64/See AGENTS.md for contributor notes.
Optional bundled fonts: place .ttf / .otf / .ttc under fonts/ (see fonts/README.txt).
Dictionary code is in this repo (src/WordLookup.cpp, etc.). Dictionary data files (.idx / .dat) are not included due to size and licensing; users supply their own under {exe}\dict\.
Sumatra PDF Plus is a community modification for testing and personal use. Bug reports and pull requests are welcome on this repository only — not on the official SumatraPDF issue tracker.
SumatraPDF is a multi-format (PDF, EPUB, MOBI, CBZ, CBR, FB2, CHM, XPS, DjVu) reader for Windows under (A)GPLv3 license, with some code under BSD license (see AUTHORS).
More Information: