class

Phosphor::Layout

Inherits Reference < Object

Splits a Frame into sub-frames according to a list of Constraints.

Construct one via .vertical or .horizontal, then call #split with the frame to divide. Pure and stateless once built — safe to call #split every render.

See DESIGN.md § "Layout and Constraint" for the full rationale.

Constructors

horizontal(constraints : Array(Constraint), flex : Flex = Flex::Start) : Layout

Returns a Layout that divides a frame's width among constraints, left to right, distributing leftover space per flex.

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new(direction : Direction, constraints : Array(Constraint), flex : Flex)
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vertical(constraints : Array(Constraint), flex : Flex = Flex::Start) : Layout

Returns a Layout that divides a frame's height among constraints, top to bottom, distributing leftover space per flex.

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Instance methods

constraints

The sizing rules for each slot, in order.

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direction

Whether this layout divides the frame's height or width.

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flex

How slots are distributed within the space left over after constraints are satisfied.

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split(frame : Frame) : Array(Frame)

Splits frame into one sub-frame per constraint, in the same order as constraints.

Sizes are resolved in four passes — fixed (Length/Percentage), then Min/Max, then Fill (and Min's growth beyond its floor), then Ratio — each pass claiming from whatever space the previous pass left behind. flex then decides where any leftover space (only possible when there's no Fill or Ratio to soak it up) shifts the slots to.

Every pass claims against a shrinking budget, so constraints that don't fit shrink toward zero instead of overflowing the frame — no branch here can panic.

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Nested types