Descry

A keyboard-driven markdown editor in C, SDL2, and Lua. Aims at the Obsidian / Lite XL ergonomics — vault sidebar, wiki links, full preview rendering, plugin host — without the Electron tax.

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What works

• Live preview of CommonMark via md4c — headings, lists, task lists, code fences, block quotes, tables, inline styles, links, soft and hard breaks.
• Images in preview — local png / jpg / svg, and http(s) URLs fetched on a background thread and cached on disk. SVG goes through nanosvg plus a second pass for the <text>, logo <image> and rounded-corner <clipPath> nanosvg ignores, so a README's shields.io badges keep their labels, logos and corners.
• Edit mode with a real text buffer (undo/redo, multi-byte caret, selection, smart Enter for lists, auto-pairs, find/replace). Soft word wrap on by default; toggle off (Alt+Z) for a horizontal scrollbar with arrow buttons.
• Tabs — several files open at once, lossless switching (each tab keeps its text, cursor, scroll, and undo), reopened on next launch. A toggleable split live-preview (Ctrl+\) renders the active file source-left / preview-right.
• Vault sidebar with collapsible folders, drag-and-drop reorder, right-click context menu, recents tracking, and image files that open straight into the preview pane.
• Wiki links [[note name]] resolve case-insensitively across the vault; backlinks panel shows every note that points at the current one. Typing [[ opens an auto-complete list of every note, each row showing its path relative to the vault root so two notes called "index" stay distinguishable.
• Tags #tag are the vault's other relation: where [[…]] points at one file, #… names a subject any number of notes can share. Highlighted in both edit and preview, clickable in preview to search the vault for them, and offered by an auto-complete list (with the same path column) when you type # mid-line. The tag panel (Ctrl+Shift+G) ranks every tag in the vault by use.
• Outline panel auto-generated from headings, pinned or modal.
• Find / Replace with regex, case-insensitive, whole-word, live match count, caret-aware editing, click-to-position. Searches the raw source in edit mode and the rendered text in preview so the highlights line up in either view.
• Vault-wide search across every note with a results overlay.
• Quick switcher (Ctrl+P) — recents-first, fuzzy match.
• Command palette (Ctrl+Shift+P) — every action plus every Lua-registered plugin action with a category chip and bound shortcut.
• Plugin host — drop *.lua in data/plugins/, register actions with descry.register_action("name", fn), and do real work: read and edit the open document (descry.buffer.*), list/refresh/open vault notes (descry.vault.*, descry.open), run other actions (descry.invoke), and subscribe to open / save / text_change / mode_change / vault_change events (descry.on). Surface output with descry.notify / descry.dialog, ask with descry.confirm / descry.prompt. Declare typed settings with descry.config(key, default, {type=…}) and they get a real editor: the Plugins overlay lists every loaded file, its actions, an on/off switch, a per-plugin settings modal (toggles, choices, validated numbers) and a hot-reload button.
• LaTeX math — inline $…$ and display $$…$$ spans render typographically: Greek letters, operators, \frac{a}{b}, roots, and simple super/subscripts become real Unicode glyphs ($\sum_{i=1}^{n} x_i^2$ → ∑ᵢ₌₁ⁿ xᵢ²). A typographic pass, not a full TeX engine.
• Graph view (Ctrl+Shift+M) — a force-directed map of the vault's relation graph: one node per note, one per #tag, an edge per wiki link and per tag mention. Node size scales with degree, the current note is highlighted; drag to pan, scroll to zoom, click a note to open it or a tag to search for it.
• Navigation history — every note you open and every deliberate jump (outline heading, Go to line, a followed link) is recorded, so Ctrl+[ walks back to where you were, caret and scroll included, and Ctrl+] returns. The Go menu gathers the rest: Go to File, Line, Heading and Tag, plus "Last edit" to hop back to where you were last typing.
• Spell check — opt-in (spellcheck = true in settings.lua), dictionary-driven red squiggles under unknown words in the editor. Points at a system word list or your own dictionary_path; "Add to dictionary" remembers words in data/.dictionary_user.
• In-app modals for Save / Save As / Rename / New File — no native Win32 dialogs, full keyboard nav, sidebar-style file browser.
• Custom title bar with File / Edit / View / Help menus, aero snap, drag-to-move, min/maximize/close, working under SDL_WINDOW_BORDERLESS via a WS_THICKFRAME + WM_NCCALCSIZE trick.
• Hisashi menubar (Windows) — opt-in in Settings; File/Edit/View/Help move into Hisashi's macOS-style menubar and the in-app strip hides while connected.
• Live resize indicator — a centered W x H badge plus a window outline render while the user drags an edge. The resize loop pumps through an SDL event watch so the indicator animates during the drag, not after.
• Plugin actions, Ctrl+click external links, image preview, About dialog, settings persistence, theme picker, keybinding editor, daily-notes, HTML export, ASCII-art table aligner ...

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Screenshots

Image embeds in preview

Wiki links and quote blocks

Tags, lists, mid-line styling

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Stack

Layer	Library
Language	C11
Window / input	SDL2
Glyph cache	FreeType + HarfBuzz
Markdown parser	md4c (vendored)
Scripting	Lua 5.4 (vendored)
SVG icons / pills	nanosvg (vendored)
Image decode	libpng, libjpeg
Anti-aliasing	custom analytic signed-distance-field pill rasterizer
Build	CMake + Ninja

No GTK, no Qt, no web view, no JS runtime. The compiled binary is a single descry.exe plus its DLL dependencies (SDL2, FreeType, HarfBuzz, libpng, libjpeg).

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Building

Windows (MSYS2 MinGW-w64)

pacman -S mingw-w64-x86_64-{gcc,cmake,ninja,SDL2,freetype,harfbuzz,libpng,libjpeg-turbo}
cmake -G Ninja -B build
ninja -C build
./build/descry.exe

build.ps1 wraps the same two commands and additionally bundles the MinGW runtime DLLs next to the exe; build.ps1 -Installer packages dist/Descry-Setup-<version>.exe.

Windows Defender false positives

A freshly built descry.exe can be quarantined as Trojan:Win32/Bearfoos.A!ml. The !ml suffix means a machine-learning verdict rather than a signature match, and Bearfoos.A is Defender's catch-all bucket for unsigned binaries it has never seen before. Descry is clean — VirusTotal agrees — but a brand-new unsigned build starts from zero reputation, so the build is set up to give the classifier as little to work with as possible:

• resources/descry.rc.in stamps a full VERSIONINFO block (company, product, description, version) into the exe, generated from the DESCRY_VERSION define in src/version.h so it cannot drift.
• The exe links with --dynamicbase --high-entropy-va --nxcompat, so it opts into ASLR and DEP instead of shipping with MinGW's defaults off.
• lua_host_create() removes os.execute, os.exit, io.popen and package.loadlib from the plugin sandbox, so the embedded interpreter cannot spawn processes or load native code.
• The Forge installer is no longer built stripped (-s -w).

The durable fix is a code-signing certificate. tools/sign.ps1 signs whatever you point it at when DESCRY_SIGN_THUMBPRINT or DESCRY_SIGN_PFX is set in the environment, and build.ps1 -Sign routes the exe (and the installer, with -Installer) through it. For local work only, tools/make-dev-cert.ps1 mints a self-signed certificate and trusts it on this machine; that helps nobody else's computer. If Defender is eating your builds mid-iteration, run tools/dev-defender-setup.ps1 from an elevated shell — it restores what was quarantined and excludes build/, dist/ and the install directory.

macOS (Homebrew)

Apple Silicon and Intel both work; the app renders crisp on Retina and falls back to system fonts (Menlo) automatically.

brew install cmake ninja pkg-config sdl2 freetype harfbuzz libpng jpeg
# Apple Silicon Homebrew lives under /opt/homebrew; on Intel use /usr/local.
# libjpeg is keg-only, so point pkg-config at it explicitly:
export PKG_CONFIG_PATH="/opt/homebrew/opt/jpeg/lib/pkgconfig:/opt/homebrew/lib/pkgconfig"
cmake -G Ninja -B build
ninja -C build
./build/descry

Package as a double-clickable app. To get a self-contained Descry.app (SDL/FreeType/HarfBuzz dylibs bundled inside, HiDPI-aware, ad-hoc signed so it launches locally) instead of running the binary from a terminal:

brew install dylibbundler      # bundles the dylibs into the app
./package_macos.sh             # -> build/Descry.app
./package_macos.sh --dmg       # also -> dist/Descry-<version>.dmg (drag to /Applications)

For distribution to other Macs, sign with a Developer ID (--sign "Developer ID Application: …") and notarize.

Linux

apt install build-essential cmake ninja-build libsdl2-dev libfreetype-dev libharfbuzz-dev libpng-dev libjpeg-dev
cmake -G Ninja -B build
ninja -C build
./build/descry

On Windows the build pulls every transitive MinGW DLL next to the exe via file(GET_RUNTIME_DEPENDENCIES) so the build dir is portable — zip it and run anywhere without an MSYS2 install. The data/ folder is not copied; the exe loads data/ from its own directory at runtime, so put your vault wherever you like and point Descry at it.

The repo ships thin wrappers around the commands above: build.ps1 for Windows (MSYS2 MinGW-w64) and build.sh for macOS/Linux. Both configure + build into build/; pass -Run / --run to launch afterwards.

macOS notes

• Retina / HiDPI renders at native pixel density — glyphs are rasterized at the display scale while layout stays in logical points, so text is sharp rather than upscaled. Crossing between a Retina and a non-Retina display re-rasterizes the fonts automatically.
• Fonts default to Menlo and fall back through Apple Symbols, PingFang and Apple Color Emoji for symbols / CJK / emoji. A settings.lua copied from another OS that points at a missing font is detected and swapped for the platform default instead of failing to start.
• Cmd is the accelerator. Every shortcut listed under Keyboard uses ⌘ here, shown that way in the menus, the command palette and the keybindings editor. Cmd+H is the system's "hide application" and never reaches an app, so Find & Replace also answers to the platform's own ⌥⌘F.
• Reveal in Finder uses open -R; external links and the log folder open via open.
• File dialogs use AppleScript (osascript); logs and settings live under ~/Library/Application Support/fezcode/Descry/.

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Layout

src/             - C sources (single-binary)
  main.c         - app loop, UI, every overlay
  buffer.c/h     - the gap-free text buffer + cursor/selection/undo
  markdown.c/h   - md4c wrapper, line/style/wiki/link extraction
  font.c/h       - FreeType+HarfBuzz glyph cache, fallback chain
  icons.c/h      - nanosvg icon raster + SDF pill rasterizer
  lua_host.c/h   - Lua state, plugin loader, action registry, buffer/
                   vault/event bridge for plugins
  vault.c/h      - recursive directory scan + native dialogs
  image.c/h      - PNG/JPG/SVG decode -> SDL_Texture cache
  svg_extra.c/h  - the <text>/<image>/clipPath nanosvg drops, so
                   README badges render with their labels
  regex.c/h      - in-house regex engine (find/replace)
  mermaid.c/h    - mermaid diagram parse + layout
  graph.c/h      - force-directed wiki-link graph layout
  spell.c/h      - hash-set spell dictionary
  tabs.c/h       - open-file tab list + park/restore
data/            - default vault: sample notes, init.lua, plugins/
vendor/          - lua 5.4, md4c, nanosvg
resources/       - .ico, manifest, descry.rc.in (VERSIONINFO template)
tools/           - sign.ps1, make-dev-cert.ps1, dev-defender-setup.ps1

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Plugins

A plugin is any .lua file under data/plugins/. The host exposes a tiny global table:

-- data/plugins/hello.lua
descry.register_action("say_hello", function()
    descry.dialog("Hello", "Hello from the plugin system!")
end)

descry.notify("[hello plugin] loaded")

After a reload (Ctrl+Alt+P > Reload, or restart), the action shows up in the command palette with a Plugin category chip and can be invoked by name or bound to a key.

Full reference — every available API call, lifecycle, debugging, and an honest list of what's not exposed yet — lives in docs/plugins.md.

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Keyboard

A non-exhaustive list. Every binding is editable from Settings > Keybindings and persists to settings.lua next to the exe.

On macOS the accelerator is Cmd, not Ctrl — read every Ctrl+… below as ⌘…. The bindings themselves are stored with the portable ctrl+ spelling, so a settings.lua moves between machines unchanged; only the physical key differs. Control is left alone for the text motions the platform reserves it for.

Action	Shortcut
Toggle edit / preview	Ctrl+E
Save	Ctrl+S
Save As	Ctrl+Shift+S
New file	Ctrl+N
Rename	F2
Quick switcher	Ctrl+P
Back / Forward	Ctrl+[ / Ctrl+]
Go to line	Ctrl+G
Command palette	Ctrl+Shift+P
Plugins overlay	Ctrl+Alt+P
Find	Ctrl+F
Find / Replace	Ctrl+H (Alt+Ctrl+F)
Vault search	Ctrl+Shift+F
Outline	Ctrl+Shift+O
Backlinks	Ctrl+Shift+B
Tags	Ctrl+Shift+G
Graph view	Ctrl+Shift+M
Daily note	Ctrl+D
Toggle sidebar	Ctrl+B
Toggle word wrap	Alt+Z
Help & Keybindings	F1
Settings	Ctrl+, or F10

When word wrap is off, long edit-mode lines extend past the viewport; Shift+wheel pans, or use the horizontal scrollbar that appears at the bottom of the editor. In preview, a table wider than the pane gets its own horizontal scrollbar beneath it — drag the thumb, or hover the table and use Shift+wheel or a horizontal swipe.

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Author

fezcode