PixelKit

PixelKit brings the Microsoft PowerToys Color Picker and Screen Ruler workflows to Linux. It also includes a standalone magnifier and a QR and barcode scanner. The whole application ships as one Rust binary and keeps its data on your machine. It works on X11 and Wayland without privileged input or capture hooks.

PixelKit is independent of Microsoft and PowerToys. This project uses the adjacent PowerToys source tree as an MIT-licensed behavioral reference.

Demo

Screencast_20260715_141803_trimmed_54s.mp4

What PixelKit does

Color picker, magnifier, and editor

The color picker is a fullscreen overlay that samples the original, full-resolution capture. On a multi-monitor setup, each capture appears on the monitor it came from. Large captures are split into lossless GPU-safe tiles instead of being resized.

• The 13×13 loupe has tooltip and pointer-centered layouts, with up to 255 zoom levels controlled by the mouse wheel.
• The standalone magnifier has centered-grid and tooltip layouts. Its starting and maximum zoom, grid size, cursor, Wayland capture behavior, and shortcut are configurable.
• Arrow keys move one pixel. Hold Shift to move ten pixels at a time.
• Primary, middle, and secondary clicks can pick then edit, pick and close, or close without copying.
• Enter and Space pick a color. Escape and Backspace cancel. Escape also closes the editor opened after a pick.
• PixelKit keeps a de-duplicated color history; you choose how many entries it retains.
• The editor has RGB and HSV controls, three- or six-digit HEX input, four related color variations, and human-readable names based on the PowerToys bucket algorithm.
• History can be exported as JSON or text, grouped by color or format.
• Sixteen formats are built in: HEX, RGB, HSL, HSV, CMYK, HSB, HSI, HWB, NCol, CIE XYZ, CIE LAB, Oklab, Oklch, VEC4, Decimal, and HEX Int.
• Custom formats support PowerToys tokens such as %ReX, %Gr, %Hu, %Sl, %Na, and the full CIE and Oklab parameter set.

QR and barcode scanner

The scanner checks the original full-resolution capture on a worker thread, so the overlay stays responsive.

• Multiple codes in one image get numbered, clickable highlights.
• Outline and number-badge color and opacity are configurable.
• Supported formats include QR, Micro QR, Data Matrix, Aztec, PDF417, Code 39, Code 93, Code 128, EAN, UPC, ITF, Codabar, GS1 DataBar, Telepen, and MaxiCode.
• The result view shows the decoded format and complete text, with a button to copy it to the clipboard.
• HTTP and HTTPS results get an explicit Open link action. PixelKit shows the destination first, then hands it to the desktop portal.
• Recapture or R takes a new snapshot and scans it without including the PixelKit overlay.

Screen ruler

The ruler measures rectangles and same-color spacing in cross, horizontal, and vertical modes.

• Set a sum-of-RGB or per-channel edge tolerance from 0 to 255. The mouse wheel adjusts it in 15-point steps.
• Configure the crosshair color and end caps.
• Read measurements in pixels, inches, centimetres, or millimetres. PixelKit uses physical display data on X11 and a configurable fallback DPI on Wayland.
• Shift-click keeps several measurements on screen. Copying includes every retained measurement.
• Touch and pointer input are supported. Right-click cancels, Ctrl+1 through Ctrl+4 selects a tool, and snapshot recapture does not block the UI.
• During continuous capture on X11, PixelKit uses a transparent blank/capture cycle so its own lines do not appear in the sampled image.

Linux integration

• Direct, low-latency X11 root capture and native key grabs.
• xdg-desktop-portal Screenshot and GlobalShortcuts interfaces on Wayland and inside Flatpak.
• A background shortcut daemon that does not poll the screen while idle.
• Desktop actions, AppStream metadata, scalable and high-resolution icons, man page, and systemd user unit.
• No telemetry, cloud service, root helper, or setuid binary. Decoded content stays local. Only a link you choose to open is handed to the desktop.

The shortcut daemon waits for events while idle. It does not initialize the GUI, decoder, or screen capture until you launch a tool.

X11 and Wayland behavior

Capability	X11	Wayland and Flatpak
Screen capture	Immediate direct capture	Screenshot portal. The compositor may ask for permission or a target
Picker, magnifier, scanner, and ruler overlays	One exact full-screen crop per monitor	One exact crop per monitor if XWayland geometry matches the portal image. Otherwise, one fullscreen portal snapshot
Global shortcuts	X11 key grab	GlobalShortcuts portal. The compositor chooses the final binding
Continuous ruler background	Live transparent recapture	Use Recapture or press R after the underlying content changes. The Screenshot portal is request-based
Clipboard	Native X11 selection	Native Wayland data control plus GUI clipboard fallback

Wayland does not let regular applications silently capture other windows or install global key grabs. The permission or target dialog is expected and does not mean a package permission is missing. PixelKit uses the screenshot portal for capture and XWayland only to position its overlays. If it cannot match the portal image to the monitor geometry, it displays the snapshot in one fullscreen overlay.

If your desktop does not provide the GlobalShortcuts portal, assign these commands in the desktop's keyboard settings:

pixelkit color-picker
pixelkit magnifier
pixelkit code-scanner
pixelkit screen-ruler

Install from package repositories

Published x86_64 packages are available in the Fedora Copr repository and the openSUSE Build Service project. There is also an AUR package for Arch Linux.

Fedora 44 and Rawhide

sudo dnf copr enable kuchen/pixelkit
sudo dnf install pixelkit

Arch Linux with AUR

Install with an AUR helper such as yay:

yay -S pixelkit

Or build and install the package manually:

git clone https://aur.archlinux.org/pixelkit.git
cd pixelkit
makepkg -si

Debian 13 and Ubuntu 24.04/26.04

Choose the repo value that matches your distribution, then add the OBS signing key and APT source:

repo=xUbuntu_24.04 # Debian_13, xUbuntu_24.04, or xUbuntu_26.04
base="https://download.opensuse.org/repositories/home:/kuchen:/PixelKit/$repo"

sudo apt install curl gpg
sudo install -d -m 0755 /etc/apt/keyrings
curl -fsSL "$base/Release.key" | gpg --dearmor | \
  sudo tee /etc/apt/keyrings/pixelkit-obs.gpg >/dev/null
echo "deb [signed-by=/etc/apt/keyrings/pixelkit-obs.gpg] $base/ /" | \
  sudo tee /etc/apt/sources.list.d/pixelkit-obs.list
sudo apt update
sudo apt install pixelkit

The OBS signing-key fingerprint is C246 A272 BD2F B2A0 4044 ECDA C7C1 26FB 1D6D 878E.

Install from source

To build PixelKit, you need Rust 1.88 or newer, GCC, make, and the usual X11, Wayland, and OpenGL runtime libraries. The Rust dependencies do not need GTK or Qt development headers.

cargo test --all-targets --locked
cargo build --release --locked
sudo make install

For a user-only installation:

./scripts/install-user.sh

Run PixelKit

Run pixelkit to open the main window. You can also launch each tool directly:

pixelkit color-picker
pixelkit magnifier
pixelkit color-editor
pixelkit code-scanner
pixelkit screen-ruler

On X11, the default shortcuts are Super+Shift+C for the picker, Super+Shift+Z for the magnifier, Super+Shift+Q for the scanner, and Super+Shift+M for the ruler. You can edit all four under Background shortcuts. On Wayland, the compositor owns the final key assignments.

Enable background shortcuts for native packages:

systemctl --user reenable pixelkit.service
systemctl --user restart pixelkit.service

The reenable command also removes obsolete early-start links left by older PixelKit packages. This keeps the daemon from starting before the graphical session is ready.

On Wayland, the desktop owns the active key combinations. If it registered the actions without assigning keys, open its PixelKit shortcut page with:

pixelkit configure-shortcuts

Building packages

The repository contains build definitions for the package formats listed below. Release builds use the locked dependency graph. Distribution builds can use the vendored source archive from make dist, so they do not need network access in the build sandbox.

Use scripts/build-packages.sh as the main entry point. It refreshes Flatpak's locked Cargo source hashes, runs the available checks once, reuses the release binary where possible, and writes a verified dist/SHA256SUMS:

./scripts/build-packages.sh --list
./scripts/build-packages.sh

With no format argument, the script builds every format supported by the tools installed on your machine. To build specific formats, name them explicitly, for example ./scripts/build-packages.sh rpm deb.

To start a new upstream release, run:

./scripts/build-packages.sh --clean --set-version 0.1.1

This updates Cargo, the lockfile, distribution package definitions, Flatpak, Snap, Nix, AppStream, and the manual page. It also resets the RPM, Debian, and Arch package revisions for the new version. To package another revision of the same upstream version, use --bump "Short changelog summary" instead. Neither option commits, tags, pushes, or publishes anything.

After the tagged GitHub release and its checksum manifest are public, publish the matching vendored archive to the AUR with:

./scripts/publish-aur.sh

Add --no-push to prepare and verify the source without publishing it.

make packages calls the same script. Pass optional arguments through PACKAGE_ARGS. If you have an RPM builder but not the development packages from the spec, --list prints the missing package names. On Fedora, install all of them with sudo dnf builddep packaging/rpm/pixelkit.spec.

Ecosystem	Definition	Build command
Flatpak / Flathub	packaging/flatpak/	./scripts/build-packages.sh flatpak
Fedora / RHEL / DNF	packaging/rpm/pixelkit.spec	./scripts/build-packages.sh rpm
openSUSE / Zypper	packaging/opensuse/pixelkit.spec	./scripts/build-packages.sh opensuse
Debian / Ubuntu / APT	debian/	./scripts/build-packages.sh deb-source
Arch / pacman / AUR	packaging/arch/PKGBUILD	./scripts/build-packages.sh arch
Snap Store	snap/snapcraft.yaml	./scripts/build-packages.sh snap
Nix / NixOS	flake.nix	./scripts/build-packages.sh nix
AppImage	packaging/appimage/build-appimage.sh	./scripts/build-packages.sh appimage

See the packaging and release guide for namespace ownership, checksums, repository submission, and validation details.

Configuration

PixelKit stores its settings and color history as readable, version-tolerant JSON:

• ${XDG_CONFIG_HOME:-~/.config}/pixelkit/settings.json
• ${XDG_DATA_HOME:-~/.local/share}/pixelkit/history.json

Run pixelkit paths to print the exact locations. If the settings file is corrupt, PixelKit leaves the history alone, reports the error in the UI, and loads safe defaults.

Development and tests

cargo check --all-targets --locked
cargo test --all-targets --locked
cargo run -- formats '#ff0000'
cargo run -- color-picker --image test-screen.png
cargo run -- magnifier --image test-screen.png
cargo run -- code-scanner --image test-screen.png
cargo run -- screen-ruler --image test-screen.png

The --image option runs the same picker, magnifier, scanner, and ruler UI and algorithms without requesting a desktop capture. Before a release, test on X11 and Wayland, especially with multiple monitors and mixed scale factors.

License and attribution

PixelKit is licensed under MIT. NOTICE lists the PowerToys and barcode decoder attribution. Third-party Rust crates keep their own licenses. Use cargo deny and the distribution tools to produce the dependency license inventory for a release.