Vernier

Cross-platform pixel-measurement overlay in Rust. Runs on macOS, Windows, Linux X11 + Wayland. Linux/Wayland (Hyprland on Omarchy) is the primary development target.

Status

Pre-alpha. Milestone 1 (skeleton) complete on Hyprland: workspace, transparent layer-shell overlay, tray icon, global hotkey via the GlobalShortcuts portal, and IPC fallback for compositors that need a direct keybind.

Building

Requires 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

Running on Hyprland (Omarchy)

./target/debug/vernier            # daemon, foreground
./target/debug/vernier toggle     # toggle the running daemon's overlay
./target/debug/vernier quit       # tell the running daemon to quit

Tray icon

The daemon registers a StatusNotifierItem. waybar's tray module renders it. The default Omarchy waybar config is already wired up — the icon appears in the tray-expander group on the right side of the bar. Left-click to open the menu (Preferences, Quit).

If your waybar lacks the tray module, add:

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

Hotkey

The default toggle is CTRL+SHIFT+ALT+SUPER+F (configurable in the prefs window's Shortcuts pane).

On Hyprland: zero setup. On startup the daemon runs hyprctl keyword bind = …, exec, vernier toggle itself and re-applies the bind on configreloaded, so the shortcut Just Works — no edits to ~/.config/hypr/hyprland.conf required. The runtime bind is cleared when the daemon exits.

On other wlroots compositors / portal-only setups. The daemon also registers a GlobalShortcuts portal entry named hk_1 via xdg-desktop-portal-hyprland (1.3+). To map an actual key to it, add to ~/.config/hypr/hyprland.conf:

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

Manual CLI bind. If you'd rather keep the bind explicit in your own config and skip the auto-install, bind directly to the toggle subcommand:

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

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

Layout

Cargo workspace:

crates/
├── vernier-core/      algorithms, geometry, settings
├── vernier-platform/  Platform trait + per-OS impls
├── vernier-ui/        egui screens (prefs, HUD)
└── vernier-app/       binary

vernier-platform exposes a single Platform trait the rest of the codebase binds against. Linux backend autoselects Wayland when $WAYLAND_DISPLAY is set, otherwise X11. macOS and Windows backends are stubs pending later milestones.