layout

package
v1.5.3 Latest Latest
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 Go to latest Published: Jun 26, 2026 License: Apache-2.0 Imports: 1 Imported by: 0

Documentation

Overview

Package layout provides a pure-geometry layout engine for the Arena TUI. It computes rectangles for a tree of panes and contains no rendering code.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func RenderTree 

func RenderTree(root *Node, content map[string]string) string

RenderTree composes the rendered content of each leaf into the layout's shape. content maps a leaf ID to its already-rendered string. Vertical splits stack with JoinVertical(Left); horizontal splits sit side by side with JoinHorizontal(Top). Invisible nodes are skipped. Unlike the geometry files, this rendering layer may depend on lipgloss.

func Solve 

func Solve(root *Node, area Rect) map[string]Rect

Solve computes the rectangle for every leaf in the tree rooted at root, laid out within area. Leaf rectangles are keyed by Node.ID. Invisible nodes are omitted. Solve is a pure function: same inputs always yield the same map.

Types

type Direction 

type Direction int

Direction is the axis along which a split arranges its children. 

const (
	// Vertical stacks children top to bottom.
	Vertical Direction = iota
	// Horizontal places children left to right.
	Horizontal
)

type Manager 

type Manager struct {
	// contains filtered or unexported fields
}

Manager owns a layout tree and its current area, and is the single place that mutates the layout at runtime (resize, collapse). Each mutation reflows once, so consumers read the resulting rects via Rect. Construct page trees with the builders and hand the root to NewManager.

func NewManager 

func NewManager(root *Node) *Manager

NewManager returns a Manager for the given layout tree.

func (*Manager) Grow 

func (m *Manager) Grow(id string, delta int)

Grow adjusts the flex weight of the leaf with the given ID by delta (weight is clamped to a minimum of 1) and reflows. Growing a fixed-size leaf has no effect. Unknown IDs are ignored.

func (*Manager) Rect 

func (m *Manager) Rect(id string) (Rect, bool)

Rect returns the computed rectangle for the leaf with the given ID. The second result is false when the leaf is collapsed (absent from the layout).

func (*Manager) Root 

func (m *Manager) Root() *Node

Root returns the layout tree, for composition via RenderTree.

func (*Manager) SetArea 

func (m *Manager) SetArea(r Rect)

SetArea sets the available area and reflows.

func (*Manager) ToggleCollapse 

func (m *Manager) ToggleCollapse(id string)

ToggleCollapse flips the visibility of the leaf with the given ID and reflows. Unknown IDs are ignored.

type Node 

type Node struct {
	ID       string
	Dir      Direction
	Children []*Node

	Mode    SizeMode
	Size    int
	Weight  int
	MinW    int
	MinH    int
	Visible bool
}

Node is one element of a layout tree. A node is either a leaf (ID set, no Children) or a split (Children set). Construct nodes with the builders rather than literals so defaults (Visible, Weight) are set correctly.

func Fixed 

func Fixed(size int, child *Node) *Node

Fixed makes child claim exactly size cells along its parent's axis.

func Flex 

func Flex(weight int, child *Node) *Node

Flex makes child share leftover space proportional to weight.

func HSplit 

func HSplit(children ...*Node) *Node

HSplit returns a horizontal split whose children sit left to right.

func Optional 

func Optional(visible bool, child *Node) *Node

Optional includes child in the layout only when visible is true.

func Pane 

func Pane(id string, opts ...Option) *Node

Pane returns a leaf node. It is flex with weight 1 and visible by default.

func VSplit 

func VSplit(children ...*Node) *Node

VSplit returns a vertical split whose children stack top to bottom.

func (*Node) IsLeaf 

func (n *Node) IsLeaf() bool

IsLeaf reports whether n has no children.

type Option 

type Option func(*Node)

Option configures a Node during construction.

func Min 

func Min(w, h int) Option

Min sets the minimum width and height in cells.

func Weight 

func Weight(w int) Option

Weight sets the flex weight (share of leftover space).

type Rect 

type Rect struct {
	X, Y, W, H int
}

Rect is a position and size in terminal cells.

type SizeMode 

type SizeMode int

SizeMode controls how a node claims space within its parent split. 

const (
	// ModeFlex shares leftover space proportional to Weight.
	ModeFlex SizeMode = iota
	// ModeFixed claims exactly Size cells along the parent's axis.
	ModeFixed
)

Source Files

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