Native plugins for Double Commander on macOS, built to a consistent engineering standard: universal binaries (Apple Silicon + Intel), headless tests, CI, and a layered safety gate before anything ships.
Five plugins cover Markdown, e-books, images and PDFs, spreadsheet previews, and media metadata. The viewers open inside Double Commander's F3 viewer and Quick View. All use the Total Commander WLX/WDX plugin ABI and work offline.
This repo is also a worked example of how I build small native tools end-to-end — investigate the platform, prove the mechanism with a focused test before writing the feature, fix root causes instead of papering over them, and keep the result reproducible and documented.
| Plugin | Type | What it does | Status |
|---|---|---|---|
markdown-wlx |
WLX (lister) | Renders Markdown beautifully in DC's viewer (F3) — GitHub-style CSS, syntax highlighting, tables, task lists, Mermaid diagrams, KaTeX math, configurable light/dark. Search, copy, and print or save as PDF with Page N of M footers. Toggle back to raw text anytime. | ✅ stable |
media-info-wdx |
WDX (content) | Shows media metadata in custom columns & tooltips — image/video resolution, audio/video duration, bitrate, codecs, PDF page count, plus an adaptive Summary field. Native ImageIO / AVFoundation / CGPDF; no deps, no network. |
✅ stable |
book-wlx |
WLX (lister) | Reads EPUB and FictionBook (FB2) e-books in the viewer (F3) — contents sidebar, continuous reflowable text, cover, reading progress, adjustable text size, light/dark/sepia. Served straight out of the container in-process: nothing unpacked to disk, nothing fetched from the network. | ✅ stable |
image-wlx |
WLX (lister) | Views images and PDFs in the viewer (F3) and Quick View with real zoom and pan — pinch, Cmd+scroll, Cmd+= / Cmd+-, drag — and vector-sharp SVG at any zoom. 60+ formats via ImageIO (HEIC, WebP, AVIF, RAW, animated GIF…); continuous PDF scrolling and PDF text selection/copy; pixel size, format and file size in the toolbar. | 🆕 new |
table-wlx |
WLX (lister) | Previews CSV/TSV, Excel, Apple Numbers and OpenDocument spreadsheets as a native grid. Select cells or rectangular ranges, copy TSV values, switch worksheets and search. Offline, read-only. | 🆕 new |
More plugins will follow; the repo layout and the contributor guide are built for that.
Press F3 on any .md file and it opens rendered. The built-in viewer's mode
switch still lets you flip to the raw Text view (and back) at any time.
F3 on an .epub, .fb2 or .fbz opens the book itself — contents sidebar,
continuous reflowable text, cover and reading progress — instead of the container.
F3 (or Quick View) on an image opens it fitted to the window, then pinch, Cmd+scroll or Cmd+= / Cmd+- to zoom and drag to pan. SVG is redrawn as vectors at every zoom, so a large diagram stays sharp, and pans smoothly, at 1600%. PDFs scroll continuously with PgUp/PgDn and the same zoom controls. Drag to select PDF text, Cmd+C to copy it, or Option-drag to pan. Image-only scans require OCR elsewhere.
TableView opens CSV/TSV, Excel, modern single-file Numbers and ODS/FODS files as a native grid. Select cells, rows, columns or a rectangular range and press Cmd+C to copy values as TSV. Switch worksheets and search with Cmd+F. It is a bounded, read-only data preview: formulas use cached results, and charts and spreadsheet page layouts are not rendered.
Requires macOS 11+. Download the bundle for the plugin you want; each release
contains a universal binary, installer and SHA-256 checksum. No Xcode is needed
for these bundles. Unzip, quit Double Commander, then run ./install.sh.
| Plugin | Current release |
|---|---|
| TableView | 0.1.0 |
| ImageView | 0.2.0 |
| MarkdownView | 0.5.1 |
| BookView | 0.2.0 |
| MediaInfo | 0.2.0 |
To build from source, install the Xcode command-line tools (xcode-select --install).
Every plugin builds and installs the same way:
cd table-wlx # or image-wlx, book-wlx, markdown-wlx, media-info-wdx
./build.sh # → build/<Plugin>.wlx|wdx (universal: arm64 + x86_64)
# Quit Double Commander first (it rewrites its config on exit), then:
./install.sh # installs to ~/Library/Preferences/doublecmd/ and registers itPrebuilt bundles that need no Xcode are on the
releases page: unzip,
quit Double Commander, run ./install.sh.
Per-plugin details — supported extensions, how it works, uninstall — live in each
plugin's own README (e.g. book-wlx/README.md).
A Double Commander plugin is a native shared library with a fixed C entry-point
table (the Total Commander plugin ABI). A WLX lister plugin like markdown-wlx
or book-wlx is a .wlx Mach-O dylib exporting ListLoad, ListLoadNext, ListCloseWindow,
ListGetDetectString, ListSetDefaultParams, and ListSendCommand. On macOS the window handles in
that ABI are NSView*, so a viewer plugin builds an NSView (a WKWebView for
the Markdown and e-book viewers, native AppKit views for the image/PDF and table viewers)
and hands it back to DC. A WDX content plugin like media-info-wdx is a .wdx
dylib exporting ContentGetSupportedField / ContentGetValue instead — it returns
data fields DC renders in custom columns and tooltips rather than a view.
The deeper design — the ABI, the rendering pipeline, and a couple of instructive
macOS gotchas (e.g. why WKWebView swallows the Escape key, and the fix) — is in
the project wiki and summarized in docs/ARCHITECTURE.md.
Every plugin in this collection aims to hold the same bar:
- Native & universal — one
.wlxruns on Apple Silicon and Intel (lipoverified). - Tested — a headless harness loads the real built plugin and asserts behavior (it renders; Escape reaches the host). GUI-bound tests run locally; CI verifies the build, architectures, and exported ABI symbols.
- Reproducible — third-party assets are vendored and attributed; the build is a single script with no hidden state.
- Safe to publish — a generic
leak-guardgate (secrets, private paths, OS cruft) runs in CI and as a pre-commit hook. - Root-cause fixes — bugs are understood before they're patched; see the Escape-key case study in the wiki.
.
├── markdown-wlx/ # Markdown lister plugin (WLX): renders .md in the viewer
├── book-wlx/ # e-book lister plugin (WLX): reads EPUB and FB2 books
├── image-wlx/ # image/PDF lister (WLX): zoom, pan, SVG, PDF text selection
├── table-wlx/ # table lister (WLX): CSV, Excel, Numbers, OpenDocument
├── media-info-wdx/ # media-metadata content plugin (WDX): dimensions, duration, …
├── docs/ # cross-plugin docs (architecture, adding a plugin)
├── scripts/leak-guard.sh # generic pre-publish safety gate
├── .github/ # issue/PR templates, CI workflow
├── CONTRIBUTING.md
├── CHANGELOG.md
└── LICENSE # MIT
See CONTRIBUTING.md for the build/test loop, the plugin layout convention, and docs/ADDING-A-PLUGIN.md for scaffolding a new one. Issues and proposals are welcome via the templates.
MIT © Nikolai Sachok. Bundled third-party libraries keep their own licenses —
see each plugin's THIRD_PARTY_LICENSES.md.