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Loop allows you to create custom window actions that go beyond the built-in presets. With custom actions, you can define exact window positions and sizes using either percentages or pixel values.

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Creating a Custom Action

Custom actions are created in the Keybinds settings tab:
  1. Click Add to create a new keybind
  2. Select the action dropdown and choose Custom
  3. Configure the position, size, and units
  4. Assign a keyboard shortcut (optional)
  5. Give your action a descriptive name (optional)

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WindowAction Structure

Custom actions are represented by the WindowAction struct with specific properties: 
struct WindowAction {
    var direction: WindowDirection  // Set to .custom
    var name: String?              // Optional custom name
    var unit: CustomWindowActionUnit?
    var anchor: CustomWindowActionAnchor?
    var width: Double?
    var height: Double?
    var xPoint: Double?
    var yPoint: Double?
    var positionMode: CustomWindowActionPositionMode?
    var sizeMode: CustomWindowActionSizeMode?
}
Defined in source/Loop/Window Management/Window Action/WindowAction.swift:15

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Units

Custom actions support two unit types for measurements:

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Pixels

Absolute pixel measurements for precise control: 
enum CustomWindowActionUnit {
    case pixels = 0  // Suffix: "px"
    case percentage = 1  // Suffix: "%"
}
Example: A window that’s exactly 1200px wide and 800px tall

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Percentage

Relative measurements based on screen size: 
// 50% width = half the screen width
// 100% height = full screen height
Example: A window that takes up 66.67% width and 50% height Defined in source/Loop/Window Management/Window Action/Custom Window Sizes/CustomWindowActionUnit.swift:10

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Position Modes

Control how your custom action positions windows:

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Generic Mode

Use predefined anchors to position the window: 
enum CustomWindowActionPositionMode {
    case generic = 0      // Use anchor points
    case coordinates = 1  // Use exact x/y coordinates
}
With generic mode, you select an anchor point that determines where the window is positioned on the screen. Defined in source/Loop/Window Management/Window Action/Custom Window Sizes/CustomWindowActionPositionMode.swift:10

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Coordinates Mode

Specify exact x and y coordinates for precise positioning:
  • xPoint - Horizontal position from the left edge
  • yPoint - Vertical position from the top edge
Coordinates use the same unit (pixels or percentage) as the size.

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Anchors

When using generic position mode, anchors determine where your window is positioned: 
enum CustomWindowActionAnchor {
    case none = -1
    case topLeft = 0
    case top = 1
    case topRight = 2
    case right = 3
    case bottomRight = 4
    case bottom = 5
    case bottomLeft = 6
    case left = 7
    case center = 8
    case macOSCenter = 9  // Special center mode matching macOS behavior
}
Defined in source/Loop/Window Management/Window Action/Custom Window Sizes/CustomWindowActionAnchor.swift:11

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Anchor Visualizations

Each anchor corresponds to a built-in window action for easy visualization:
  • topLeft → Top Left Quarter
  • top → Top Half
  • topRight → Top Right Quarter
  • right → Right Half
  • bottomRight → Bottom Right Quarter
  • bottom → Bottom Half
  • bottomLeft → Bottom Left Quarter
  • left → Left Half
  • center → Center
  • macOSCenter → macOS Center

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Size Modes

Control how the window size is determined: 
enum CustomWindowActionSizeMode {
    case custom = 0       // Use width/height values
    case preserveSize = 1 // Keep current window size
    case initialSize = 2  // Restore window's original size
}
Defined in source/Loop/Window Management/Window Action/Custom Window Sizes/CustomWindowActionSizeMode.swift:10

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Custom

Use the width and height values you specify.

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Preserve Size

Keep the window’s current size and only change its position. Perfect for moving windows between screens or to specific locations without resizing.
When using Preserve Size or Initial Size modes, padding will not be applied to the action.

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Initial Size

Restore the window to its original size before Loop modified it, but position it according to your anchor or coordinates.

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Example Custom Actions

A narrow sidebar on the left side of the screen:
  • Unit: Pixels
  • Position Mode: Generic
  • Anchor: Left
  • Size Mode: Custom
  • Width: 400px
  • Height: 100% (in percentage)

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Center Floating Window

A centered window with specific dimensions:
  • Unit: Pixels
  • Position Mode: Generic
  • Anchor: Center
  • Size Mode: Custom
  • Width: 1200px
  • Height: 800px

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Top-Right Note Window

Small note window in the top-right corner:
  • Unit: Pixels
  • Position Mode: Coordinates
  • X Point: Screen width - 320px
  • Y Point: 80px (below menu bar)
  • Size Mode: Custom
  • Width: 300px
  • Height: 400px

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Two-Thirds Center

Larger center window using percentages:
  • Unit: Percentage
  • Position Mode: Generic
  • Anchor: Center
  • Size Mode: Custom
  • Width: 66.67%
  • Height: 100%

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Move to Center (Preserve Size)

Move current window to center without resizing:
  • Position Mode: Generic
  • Anchor: Center
  • Size Mode: Preserve Size

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Custom Cycles

You can create cycle actions that rotate through multiple custom actions: 
init(_ name: String? = nil, cycle: [WindowAction], keybind: Set<CGKeyCode>)
Cycles allow you to press the same keyboard shortcut multiple times to step through different window positions. For example:
  1. First press: Left half
  2. Second press: Right two-thirds
  3. Third press: Full screen
  4. Fourth press: Back to left half
See Keybinds > Cycles for more information.

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Padding and Custom Actions

Padding is applied to custom actions based on the size mode: 
var isInnerPaddingApplicable: Bool {
    if direction == .undo || direction == .initialFrame {
        return false
    }
    if direction.isCustomizable, sizeMode == .initialSize || sizeMode == .preserveSize {
        return false  // No padding for these modes
    }
    return true
}
From source/Loop/Window Management/Window Action/WindowAction.swift:168
  • Custom size mode: Padding is applied
  • Preserve Size: No padding
  • Initial Size: No padding

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Naming Custom Actions

Give your custom actions descriptive names to easily identify them: 
func getName() -> String {
    if direction == .custom {
        return name?.isEmpty == false ? name! : "Custom Action"
    }
    // ...
}
If no name is provided, Loop will display “Custom Action” as the default name.

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Use Cases

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Ultra-Wide Monitor Layouts

Create custom sections for ultra-wide monitors:
  • Left third: 33.33% width, left anchor
  • Center half: 50% width, center anchor
  • Right third: 33.33% width, right anchor

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Vertical Monitor Layouts

Optimize for vertical/portrait displays:
  • Top half: 100% width, 50% height, top anchor
  • Bottom half: 100% width, 50% height, bottom anchor
  • Reading pane: 80% width, 100% height, center anchor

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Multi-Monitor Workflows

Create position presets for different screens in your multi-monitor setup, then use screen switching actions to move windows between them.

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App-Specific Layouts

Design custom window sizes for specific applications:
  • Code editor: 70% width on left
  • Browser: 30% width on right
  • Terminal: Bottom strip, 100% width × 30% height

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