Hisui PDF
A cross-platform desktop PDF editor built on a fully free/MIT-licensed stack.
Hisui PDF lets you reorganise, annotate, redact and protect PDF documents from a
single Avalonia desktop app that runs on Windows, Linux and macOS.
Download
winget (Windows)
winget install Fileman.HisuiPDF
Upgrade later with winget upgrade Fileman.HisuiPDF.
Release assets
Grab a ready-to-run build from the
Releases page — the
binaries are self-contained, so no .NET install is required.
| Platform | Asset |
|---|
| Windows x64 (installer) | HisuiPDF-Setup-X.Y.N-win-x64.exe (asks for UAC up front; works where AppLocker blocks unsigned MSIs) or HisuiPDF-X.Y.N-win-x64.msi |
| Windows x64 (portable) | Hisui.Pdf-vX.Y.N-win-x64.zip |
| Linux x64 | Hisui.Pdf-vX.Y.N-linux-x64.tar.gz |
| macOS (Intel) | Hisui.Pdf-vX.Y.N-osx-x64.tar.gz |
| macOS (Apple Silicon) | Hisui.Pdf-vX.Y.N-osx-arm64.tar.gz |
The release tag is vX.Y.N: X.Y is chosen when releasing, N is the commit count of the released build.
On Windows run the MSI (it is unsigned, so SmartScreen/UAC will warn), or unpack
the zip. On Linux/macOS unpack the archive and run Hisui.Pdf.App. On macOS the
binary is unsigned, so on first launch right-click → Open (or run
xattr -dr com.apple.quarantine Hisui.Pdf.App).
Releases started with the prerelease option are published as pre-releases.
Updates
Hisui PDF checks GitHub for a newer stable release at startup (disable with "CheckForUpdates": false in
%APPDATA%\Hisui.PDF\settings.json) and from ? Help → Check for updates…. On Windows, accepting
downloads the MSI and runs it as an in-place upgrade; on other platforms it opens
the release page. Pre-releases are never offered.
Features
- Pages — merge, split, extract, reorder, rotate and delete pages, with
non-destructive editing and full undo/redo. Multiple documents in tabs, with
an unsaved-changes prompt on close.
- Annotations — highlight, rectangle, free text, sticky notes, image
overlays, editable watermarks and header/footer with page, date and Bates
tokens (all undoable).
- Comments, bookmarks & links — real PDF comments with replies and a
comments panel; bookmarks panel (add, nest, rename, reorder); link tool with
clickable links. Saving keeps outline, links, tags and metadata.
- Reusable signatures — build a library of signatures (draw freehand, import
a PNG, or type cursive text) and reuse them across documents.
- Digital signatures (experimental) — PAdES signing with a PFX certificate,
appended as an incremental update so existing signatures stay valid; sign
into empty signature fields or invisibly; verify signatures.
- Forms — fill AcroForm fields in place (formats, required/invalid
highlight); automatic field detection; layout mode with multi-select, align,
resize, tab order and field properties; import/export data (XFDF, FDF, CSV),
reset and flatten.
- Text editing — replace a word in place (redact-and-retype).
- Redaction — secure redaction that rasterises the page and removes the
underlying text/vector content; find-and-redact by pattern (tax code, IBAN,
VAT, e-mail, phone, date, custom regex).
- Compare — text comparison with another PDF, with marks and a report.
- Standards — preflight and conversion to PDF 1.4–2.0, PDF/A-1b/2b/2u/3b/3u,
PDF/UA-1, PDF/X-4, plus an accessibility check.
- Security & metadata — AES-256 encryption, password removal, document
properties.
- Print & compress — print with preview and options (printer, copies,
duplex, page range); reduce file size by recompressing images.
- Export & extraction — convert to Word (.docx), Excel (.xlsx) and
PowerPoint (.pptx); pull out text (with coordinates) and embedded images.
- OCR — turn scanned (image-only) PDFs into searchable PDFs by adding an
invisible, selectable text layer (Tesseract, parallel across pages). Scanned
pages are detected automatically; extra languages can be downloaded on demand.
- Batch processing — apply one operation (OCR, compression, PDF/A, Word,
Excel, PowerPoint, text) to many PDFs; originals are never changed.
- Recent files — start page with a table of recent documents (thumbnail,
folder, last opened, size) and pinning.
- Localization — English and Italian UI, switchable at runtime; light, dark
or system theme (light theme meets WCAG AA contrast).
- Help & diagnostics — the ? Help button reports a problem or requests a
feature on GitHub, checks for updates and opens View log… (warnings, errors
and stack traces from
%APPDATA%\Hisui.PDF\hisui.log).
Tech stack
- .NET 10 / C#
- Avalonia 12 — cross-platform UI
- PDFsharp — structural & write operations
- PdfPig — text/image extraction
- Open XML SDK — Word (.docx) export
- PDFtoImage (PDFium) — page rendering
- Tesseract — OCR for scanned PDFs
- SkiaSharp — raster compositing
- CommunityToolkit.Mvvm + Microsoft.Extensions.Hosting — MVVM & DI
Project structure
| Project | Target | Role |
|---|
src/Hisui.Pdf.Core | net10.0 | PDF engine, no UI dependencies |
src/Hisui.Pdf.App | net10.0 | Avalonia desktop app (MVVM) |
src/Hisui.Pdf.Installer.Win | WiX 4 | Windows MSI installer |
tests/Hisui.Pdf.Core.Tests | net10.0 | xUnit v3 tests |
Build & run
# Build
dotnet build Hisui.Pdf.slnx
# Run the app
dotnet run --project src/Hisui.Pdf.App
# Run the tests (xUnit v3 on Microsoft Testing Platform — run the test exe)
dotnet test Hisui.Pdf.slnx
Packaging
Installer/package scripts live in build/: package-msi.ps1 (signed MSI via
WiX), package-win.ps1, package-linux.sh, package-osx.sh. Releases are built
by the GitHub Actions Release workflow, started manually from the Actions tab
(or gh workflow run release.yml -f version=0.1). It creates the vX.Y.N tag itself.
OCR setup
OCR works out of the box. The English and Italian language data
(eng/ita, the tessdata_fast models) ships in a tessdata folder next to
the executable, and the native engine binaries are bundled on Windows via the
Tesseract package.
- More languages — main menu → Preferences → OCR languages… downloads
other languages on demand from
tessdata_fast or imports a
.traineddata file offline. You can also drop *.traineddata files into the
tessdata folder next to the app (or point TESSDATA_PREFIX at them).
- Native libraries on Linux/macOS — install the system Tesseract/Leptonica:
on Linux
libtesseract/libleptonica, on macOS brew install tesseract leptonica.
If a language or native library is missing the app reports a clear message
instead of failing — the rest of the editor keeps working.
License
Hisui PDF is released under the MIT License.
It bundles third-party components under permissive licenses (MIT, Apache-2.0,
BSD-3-Clause) and the Inter font (SIL OFL 1.1). See
THIRD-PARTY-NOTICES.txt for the full attributions.