Sirkel

A Loop-inspired directional window snapping tool for KDE Plasma 6.7+ / KWin.

Hold a hyperkey (Caps Lock, remapped to F24), drag the mouse or press a direction key to pick where the active window should go, release to snap it there - left/right halves, top/bottom halves, or one of the four quarter corners, previewed live with an on-screen outline and a direction indicator.

Features

• Hold-and-drag or hold-and-press-a-key directional snapping to 8 positions (halves + corners), with live outline and indicator previews
• Direction selection is sticky - once picked, relaxing the mouse or releasing the keys doesn't cancel it; only picking a different direction changes it
• Holding the hyperkey alone does nothing - the indicator only appears once you actually move the mouse or press a direction key, so a reflexive tap never triggers anything
• Resting the cursor at the indicator's own center maximizes the window instead - a live zone just like the other 8 directions, with its own padding applied
• Arrow keys, WASD, or HJKL for direction (configurable preset), including combining two keys (e.g. Up+Left) for a corner - or disable direction keys entirely for mouse-only use
• Hyperkey+Enter maximizes, Hyperkey+Backspace minimizes
• Esc, or releasing with no direction chosen, cancels cleanly
• Configurable hyperkey trigger: instant (default), a hold delay, or a double-click gesture
• Optional scroll-to-resize: while a direction is picked and previewing, the mouse wheel cycles the target through a small/normal/large size before you release - edges resize only the one dimension they already control (the other stays full), Maximize shrinks width only, centered (height stays full)
• Snap to whichever monitor the cursor is on instead of always the active window's own screen (opt-in)
• Independent colors for the indicator and the outline, each sourced from a manual pick, the live Plasma accent color, or the current wallpaper (reads pywal's output, or a custom hex-color file for matugen/anything similar)
• Optional blur behind the outline's translucent fill, using KWin's own Blur effect
• Extensive, tabbed settings page (System Settings → Desktop Effects → Sirkel): Behavior, Indicator, Outline, and Colors each on their own tab

Requirements

• KDE Plasma 6.7+ (KWin with the Wayland session)
• keyd - hard dependency, used to remap Caps Lock to F24 at the input level
• Build dependencies: CMake, Extra CMake Modules (ECM), Qt6 (Core, Gui, Qml, Quick, DBus), KDE Frameworks 6 (Config, CoreAddons, GlobalAccel, KCMUtils), and KWin's own development headers

Recommended

• Geometry Change - For fancier animations when windows change positons.

Installation

1. Configure keyd

Create /etc/keyd/default.conf:

[ids]

*

[main]

capslock = f24

Then enable and start the service:

sudo systemctl enable --now keyd

This dedicates Caps Lock entirely to acting as the hyperkey.

2. Build and install the plugin

mkdir build && cd build
cmake ..
cmake --build .
sudo cmake --install .

This installs both the KWin effect itself and its System Settings configuration page.

3. Enable the effect

Open System Settings → Desktop Effects, find Sirkel, and enable it.

Usage

1. Hold Caps Lock (F24).
2. Move the mouse toward an edge or corner, or press an arrow key (or WASD/HJKL, depending on the configured scheme) - the direction indicator and a preview outline show the current pick.
3. Release Caps Lock to snap the active window there, on its own screen (windows never move across monitors).

While held:

• Enter, or resting the cursor at the indicator's own center - maximize
• Backspace - minimize
• Esc, or releasing with no direction picked - cancel without moving the window

Configuration

All settings live in System Settings → Desktop Effects → Sirkel (the configure/gear icon next to the effect), across four tabs:

• Behavior - mouse deadzone (horizontal/vertical), window padding, snap-to-cursor's-monitor toggle, keybind scheme (arrows/WASD/HJKL/none), hyperkey trigger mode (instant/delay/double-click), scroll-to-resize toggle with configurable smaller/larger percentages
• Indicator - visibility, spawn-at-cursor vs. centered, size, corner radius, ring thickness, pointer length, text label
• Outline - visibility, border thickness, corner radius, fill opacity, blur, glide/grow animation speed
• Colors - independent source per target (outline and indicator): a manual color (hex field or R/G/B/A sliders), the live theme accent color, or a wallpaper-derived color - with a "linked" toggle to keep both matched by default

Settings changes take effect automatically the next time you hold the hyperkey - no need to log out or restart the effect.

Known limitations

• Only one window is placed at a time - no multi-window "thirds" layout that's aware of its neighbors; scroll-to-resize lets you build one by hand (e.g. Left at its smaller step + Maximize at its smaller step, centered + Right at its smaller step), but each window is still placed independently
• Keybind schemes are fixed presets (arrows / WASD / HJKL / none), not arbitrary rebinding
• No dedicated action to move a window to a different monitor - "snap to cursor's monitor" changes which screen a snap targets, but there's no equivalent of Loop's screen-switching gesture yet

Comparison with Loop

How Sirkel stacks up against Loop, the macOS app it's heavily inspired by.

Feature	Loop	Sirkel
Radial menu (hold key, drag mouse, release to snap)	✅	✅
Preview window before committing	✅	✅
Modifier + arrow keys	✅	✅
Modifier + mouse	✅	✅
Halves & quarters	✅	✅
Padding/margins	✅	✅
Radial menu theming (width/shape/color)	✅	✅
Preview theming (padding, corner radius, border color/width)	✅	✅
Indicator/preview independently toggleable	✅	✅
Maximize / center gesture	✅	✅
Separate colors for indicator vs. outline	✅	✅
Thirds (horizontal/vertical, two-thirds variants)	✅	❌
Per-action custom keybinds (any key → any specific action)	✅	❌
Cycles (cycles through size variants before committing)	✅	✅ (via scroll wheel, not repeated press)
Stash (hide windows at screen edge, reveal on hover)	✅	❌
Granular manipulation (Larger/Smaller, Grow/Shrink per edge, nudge)	✅	❌
Undo last action	✅	❌
Restore initial frame (snap back to pre-Sirkel geometry)	✅	❌
Screen switching (move window to an adjacent monitor)	✅	❌
Almost Maximize / Centre as distinct actions	✅	❌
Snap via drag-to-edge (no hyperkey needed)	✅	❌

Roadmap

• Custom keybinds - real per-action global shortcuts via System Settings → Shortcuts (maximize, minimize, each directional snap, and more), replacing the current fixed arrows/WASD/HJKL preset dropdown
• Thirds - a real multi-window layout that's aware of its neighbors, rather than relying on scroll-to-resize and matching steps by hand

License

GPL-2.0-or-later.