Vernier

Native pixel-measurement overlay written in Rust. Currently supported:

• macOS — Apple Silicon, macOS 11+ (tested on 15 Sequoia).
• Linux Wayland — Hyprland is the primary development target; other wlroots compositors should work via the GlobalShortcuts portal.

Linux X11 and Windows backends exist as stubs and aren't usable yet.

Site: https://usevernier.com

Install

macOS

Download Vernier-X.Y.Z-aarch64.dmg from the latest release, drag Vernier.app into Applications, and launch it. The bundle is ad-hoc signed — the first launch shows a Gatekeeper prompt; right-click the app → Open to dismiss it once.

The daemon runs as a menu-bar item (no Dock icon). Press Cmd+, or click the V in the menu bar → Preferences to configure shortcuts and integrations.

Arch Linux (AUR)

Three flavors:

Package	Source
vernier	Builds from the tagged source tarball.
vernier-bin	Drops in the prebuilt x86_64 / aarch64 binary from the GitHub Release.
vernier-git	Builds the tip of main.

paru -S vernier-bin    # or `yay -S vernier-bin`

Omarchy Shell companion

The companion is optional. Vernier still exposes a standard StatusNotifierItem for non-Quickshell tray hosts such as Waybar and KDE. Omarchy 4.0+ users running its Quickshell-based shell can instead add Vernier as a native bar widget. This requires an active Wayland/UWSM session and network access for the Git clone; using the panel's first-launch installer also requires AUR access and a terminal in which package-manager prompts can be answered.

omarchy plugin add https://github.com/jondkinney/vernier.git --enable

Omarchy asks you to approve the third-party, unsandboxed plugin before cloning and enabling it. The widget is placed on the right side of the bar by default.

Left-click the V to open its control panel. If Vernier is not installed yet, the panel offers Install Vernier and opens a visible terminal for the AUR install, including any required prompts. It installs and verifies vernier-bin (available for x86_64 and aarch64), hands the daemon to UWSM, and the widget connects when the daemon is ready. Nothing is installed just because the widget loads.

With a companion-aware Vernier release connected, middle-click toggles measuring and right-click opens Preferences. The panel also shows the current mode and live counts for held rectangles, guides, and pinned measurements. Clicking Clear removes that content without leaving measure mode; the shortcut displayed beside it is the configured Clear & Exit shortcut and does leave measure mode when pressed. Older Vernier releases retain basic toggle, Preferences, and quit controls in legacy mode.

Update only this companion with its plugin id:

omarchy plugin update com.jondkinney.vernier

Remove it with:

omarchy plugin remove com.jondkinney.vernier

Removing the companion does not stop or uninstall Vernier; its portable tray item returns automatically. The normal omarchy update flow updates an AUR-installed Vernier package.

See packaging/omarchy/README.md for behavior, security boundaries, and development details.

Cargo (any Linux distro)

For distros without a native package, install from crates.io:

cargo install vernier-rs    # compiles from source, installs the `vernier` binary

The crate is vernier-rs because the bare vernier name was already taken; the installed binary is still vernier. You need Rust 1.85+ and the system build/runtime libraries — pkgconf plus the wayland, libxkbcommon, pipewire, fontconfig, freetype2 and libglvnd (OpenGL) dev packages (see Build from source for the exact Arch names; other distros name them similarly).

The first time you run vernier, the daemon registers itself with your application launcher — it writes vernier.desktop and the icon theme under ~/.local/share, no extra step needed. To register it before the first launch, run vernier install-desktop.

Wayland measurement activation and refresh require grim for a fresh screenshot. AUR packages install it and Flatpak bundles it; source and cargo install users must install it separately.

cargo install also can't pull in the optional capture/clipboard tools (slurp, wl-clipboard, libnotify). Run vernier doctor to see which are missing — the related features degrade gracefully until you install them.

Build from source

Rust 1.85+ (stable). System packages on Arch:

sudo pacman -S --needed \
  rust base-devel pkgconf \
  wayland wayland-protocols libxkbcommon \
  pipewire xdg-desktop-portal xdg-desktop-portal-hyprland \
  libx11 libxcb dbus \
  gtk3 libayatana-appindicator

cargo build --release
./target/release/vernier

On macOS, packaging/macos/package.sh builds the .app bundle and DMG using iconutil + create-dmg (brew install create-dmg librsvg).

Use

Ctrl+Shift+Alt+Super+F (Linux) / Ctrl+Shift+Alt+Cmd+F (macOS) toggles measure mode. Rebindable in Preferences → Shortcuts.

While measuring:

• Drag to draw a measurement rectangle. The pill shows W×H in configurable units.
• Hover the pill on a held rect → camera icon; click to capture just that region and hand off to a screenshot tool (screencapture -i on macOS, Satty / Swappy / Annotator on Wayland).
• Shift (alone) — extend the live crosshair to full-screen alignment lines.
• B / V — drop a horizontal / vertical guide; drag the guide to reposition, double-click to delete.
• Right-click — context menu (freeze stuck measurements, add guides, change edge-detection tolerance, change capture handoff target).
• Esc — clear the current rect and leave measure mode.
• Cmd+, / Ctrl+, — open the Preferences window.

The Preferences window is a separate subprocess (eframe + egui) so the long-running daemon stays tiny and the heavier UI toolkit only loads when you open it. On macOS it promotes itself to a foreground app via TransformProcessType so it can take key focus despite the daemon being LSUIElement.

Figma integration (optional)

Vernier Bridge reports the active Figma file's viewport zoom to the local Vernier process, allowing measurements to be shown in Figma canvas pixels at any zoom level. From Figma it reads only figma.viewport.zoom and whether the editor is in Design or Dev Mode; its panel also reports whether its tab is visible. It does not read or change layers, text, comments, selections, or other file content. Its only network connection is a loopback WebSocket to localhost:8765 on the same computer, where Vernier listens on 127.0.0.1.

Install the official Vernier Bridge plugin from Figma Community. Maintainers can also run the development build using Figma Desktop on macOS by following figma-plugin/README.md. Figma requires its desktop app for importing and publishing development plugins.

Zoom correction is currently focus-safe in Figma Desktop on macOS and Figma Web under Hyprland on Linux. The plugin can connect from Figma Web on other Linux desktops, but Vernier deliberately leaves measurements in ordinary screen pixels there until it has a trustworthy active-window backend. The rest of Vernier continues to work normally, with or without Figma or Quickshell.

Run Vernier Bridge once in each Figma file or tab where you want zoom-corrected measurements, then keep its small connection window open. Figma allows only one plugin to run at a time, so starting another plugin stops the bridge; run Vernier Bridge again afterward.

Hyprland setup

The Linux tray icon registers as a standard StatusNotifierItem, so a tray host such as Omarchy Shell, Waybar, or KDE can render it. Left-click opens Preferences; right-click exposes Vernier's tray menu.

When the optional Omarchy companion is loaded against a companion-aware Vernier release, it renews a short lease with the daemon and the generic item becomes passive, avoiding duplicate V icons. If Quickshell exits, reloads, or loses contact, the lease expires after 15 seconds and the generic tray item returns automatically.

If your waybar lacks the tray module:

{ "modules-right": ["tray", ...],
  "tray": { "icon-size": 16, "spacing": 8 } }

Hotkey wiring (three options)

Zero setup on Hyprland. On startup the daemon runs hyprctl keyword bind = …, exec, vernier toggle itself and re-applies the bind on configreloaded, so the shortcut Just Works. The runtime bind is cleared when the daemon exits.

Portal-based (other wlroots compositors). The daemon registers a GlobalShortcuts portal entry named hk_1 via xdg-desktop-portal-hyprland (1.3+). Map a key to it:

bind = SHIFT CTRL ALT SUPER, F, global, vernier:hk_1

Manual CLI bind. Skip the portal entirely:

bind = SHIFT CTRL ALT SUPER, F, exec, vernier toggle

vernier toggle talks to the running daemon over a Unix domain socket at $XDG_RUNTIME_DIR/vernier.sock — no portal required.

Shell integrations can use vernier status for a versioned JSON snapshot, vernier activate / vernier deactivate for idempotent control, and vernier clear to remove all held measurements without changing the active mode. vernier start starts the daemon only when it is not already responsive.

Layout

Cargo workspace:

crates/
├── vernier-core/      algorithms, geometry, settings
├── vernier-platform/  Platform trait + per-OS impls
│                      (macOS + Linux Wayland; X11 + Windows are stubs)
├── vernier-ui/        egui prefs window (separate subprocess)
└── vernier-app/       binary

vernier-platform exposes a Platform trait the rest of the codebase binds against. The HUD is rasterized in vernier-platform via tiny-skia and split into a cached static layer (held rects and stuck pills) and a dynamic layer (guides, live crosshair, cursor, toast) so pointer-driven guide placement never rebuilds the full-screen static cache.

Linux backend autoselects Wayland when $WAYLAND_DISPLAY is set; the X11 fallback isn't implemented yet.

License

MIT OR Apache-2.0, at your option. See LICENSE-MIT and LICENSE-APACHE.