Bonsplit - Native macOS Tab Bar with Split Panes

Create Tabs

Create tabs with optional icons and dirty indicators. Target specific panes or use the focused pane.

let tabId = controller.createTab(
    title: "Document.swift",
    icon: "swift",
    isDirty: false,
    inPane: paneId
)

Create Tabs

Create tabs with optional icons and dirty indicators. Target specific panes or use the focused pane.

let tabId = controller.createTab(
    title: "Document.swift",
    icon: "swift",
    isDirty: false,
    inPane: paneId
)

Split Panes

Split any pane horizontally or vertically. New panes are empty by default, giving you full control.

// Split focused pane horizontally
let newPaneId = controller.splitPane(
    orientation: .horizontal
)
// Split with a tab already in the new pane
controller.splitPane(
    orientation: .vertical,
    withTab: Tab(title: "New", icon: "doc")
)

Split Panes

Split any pane horizontally or vertically. New panes are empty by default, giving you full control.

// Split focused pane horizontally
let newPaneId = controller.splitPane(
    orientation: .horizontal
)
// Split with a tab already in the new pane
controller.splitPane(
    orientation: .vertical,
    withTab: Tab(title: "New", icon: "doc")
)

Update Tab State

Update tab properties at any time. Changes animate smoothly.

// Mark document as modified
controller.updateTab(tabId, isDirty: true)
// Rename tab
controller.updateTab(tabId, title: "NewName.swift")
// Change icon
controller.updateTab(tabId, icon: "doc.text")

Update Tab State

Update tab properties at any time. Changes animate smoothly.

// Mark document as modified
controller.updateTab(tabId, isDirty: true)
// Rename tab
controller.updateTab(tabId, title: "NewName.swift")
// Change icon
controller.updateTab(tabId, icon: "doc.text")

Navigate Focus

Programmatically navigate between panes using directional navigation.

// Move focus between panes
controller.navigateFocus(direction: .left)
controller.navigateFocus(direction: .right)
controller.navigateFocus(direction: .up)
controller.navigateFocus(direction: .down)
// Or focus a specific pane
controller.focusPane(paneId)

Navigate Focus

Programmatically navigate between panes using directional navigation.

// Move focus between panes
controller.navigateFocus(direction: .left)
controller.navigateFocus(direction: .right)
controller.navigateFocus(direction: .up)
controller.navigateFocus(direction: .down)
// Or focus a specific pane
controller.focusPane(paneId)

Geometry Sync

Two-way synchronization with external programs. Query geometry, receive change notifications, and update dividers programmatically.

// Query current geometry with pixel coordinates
let snapshot = controller.layoutSnapshot()
for pane in snapshot.panes {
    print(pane.frame.width, pane.frame.height)
}
// Set divider position from external source
controller.setDividerPosition(0.3, forSplit: splitId, fromExternal: true)

Geometry Sync

Two-way synchronization with external programs. Query geometry, receive change notifications, and update dividers programmatically.

// Query current geometry with pixel coordinates
let snapshot = controller.layoutSnapshot()
for pane in snapshot.panes {
    print(pane.frame.width, pane.frame.height)
}
// Set divider position from external source
controller.setDividerPosition(0.3, forSplit: splitId, fromExternal: true)

LayoutSnapshot

A complete snapshot of the current layout with pixel coordinates.

public struct LayoutSnapshot: Codable, Sendable {
    public let containerFrame: PixelRect    // Container bounds in screen coords
    public let panes: [PaneGeometry]        // All pane geometries
    public let focusedPaneId: String?       // Currently focused pane
    public let timestamp: TimeInterval      // Snapshot time
}

PaneGeometry

Geometry information for a single pane.

public struct PaneGeometry: Codable, Sendable {
    public let paneId: String           // Pane UUID string
    public let frame: PixelRect         // Pixel coordinates
    public let selectedTabId: String?   // Selected tab UUID
    public let tabIds: [String]         // All tab UUIDs
}

PixelRect

A rectangle in pixel coordinates for external consumption.

public struct PixelRect: Codable, Sendable {
    public let x: Double
    public let y: Double
    public let width: Double
    public let height: Double
}

ExternalTreeNode

Recursive tree representation of the split hierarchy.

public enum ExternalTreeNode: Codable, Sendable {
    case pane(ExternalPaneNode)     // Leaf node: a pane
    case split(ExternalSplitNode)   // Branch node: a split with two children
}

ExternalSplitNode

A split node in the tree with orientation and divider position.

public struct ExternalSplitNode: Codable, Sendable {
    public let id: String                    // Split UUID string
    public let orientation: String           // "horizontal" or "vertical"
    public let dividerPosition: Double       // 0.0-1.0
    public let first: ExternalTreeNode       // First child
    public let second: ExternalTreeNode      // Second child
}

ExternalPaneNode

A pane node in the tree with frame and tab information.

public struct ExternalPaneNode: Codable, Sendable {
    public let id: String               // Pane UUID string
    public let frame: PixelRect         // Pixel coordinates
    public let tabs: [ExternalTab]      // Tab info
    public let selectedTabId: String?   // Selected tab UUID
}

ExternalTab

Tab information for external consumption.

public struct ExternalTab: Codable, Sendable {
    public let id: String       // Tab UUID string
    public let title: String    // Tab title
}

Example

let config = BonsplitConfiguration(
    allowSplits: true,
    allowCloseTabs: true,
    allowCloseLastPane: false,
    autoCloseEmptyPanes: true,
    contentViewLifecycle: .keepAllAlive,
    newTabPosition: .current
)
let controller = BonsplitController(configuration: config)