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Align & Distribute

Align moves selected nodes so an edge or center coincides; distribute equalizes the spacing between them. The whole feature is one rule plus arithmetic — the rule is what frame you align to, and it flips on selection cardinality.

The reference-frame rule​

  • Two or more nodes: the frame is the selection's union bounds (world-space AABB of all members). Align-left moves every member's left edge to the union's left edge; the union itself never moves — alignment redistributes within the selection.
  • One node: the frame is the node's parent container, which stays fixed while the node moves — align-center centers the child in its parent. A single top-level node has no meaningful frame and the command declines.

There is no modifier and no threshold: cardinality alone picks the frame. (The one-node case is what makes align useful at all for a single selection; the many-node case is the classic tool.)

Geometry​

  • Alignment measures world-space axis-aligned bounds — a rotated node aligns by its world AABB, not its local box.
  • Deltas are computed in world space and applied as translations projected into each node's own parent frame — so alignment is correct when members live under different parents, including transformed ancestors. Mixed-parent selections are legal; each member moves in its own frame, the union is shared.
  • Alignment never resizes, never rotates, never re-parents.

Align and distribute are union commands: they read the whole selection as one set and never partition it by parent — the contrast to the structural commands (grouping, flatten, boolean), which act once per selection partition (PART-3). Mixed parents are handled by projecting each member's delta into its own frame, not by grouping.

Distribute​

Distribute equalizes edge-to-edge gaps along one axis:

  • Requires three or more members (with two there is nothing to distribute).
  • Members are ordered by their position along the axis; the outermost two hold their positions; interior members move so every adjacent gap equals (span − Σ sizes) / (N − 1).
  • The selection's union bounds are invariant under distribute.

Layout-owned members​

A member whose position is owned by its parent's auto-layout flow has nothing for align to author — the layout will immediately override any translated position. Such members are excluded: free members align, in-flow members stay, and an all-in-flow selection declines. This is the computed-vs-authored doctrine (properties PROP-5, nudge NUDGE-4) applied to alignment — changing arrangement inside a flow is the container's alignment property, reachable in the properties panel, not a geometric align.

Triggers and history​

The align row sits at the top of the properties panel; the keybindings are in the sheet: Alt+A/D/W/S (left/right/top/bottom), Alt+H/V (horizontal/vertical centers), and — matching the web editor — Alt+Ctrl+V distributes horizontally, Alt+Ctrl+H vertically (the distribute letter is the opposite axis of the align center on the same key). Every align or distribute action is one history entry — a multi-node align undoes in one step.

Contracts​

  • ALIGN-1 Frame flip: with N≥2 the union's aligned edge or center is invariant — align-left preserves the union's left edge, align-center its center, etc. — and every member stays within the original union (alignment redistributes inside the frame; the union's extent along the aligned axis collapses, so the whole AABB is not preserved, only the reference edge). With N=1 the parent is untouched and the node lands on the parent-frame edge/center.
  • ALIGN-2 Top-level single-node align is a no-op (declines).
  • ALIGN-3 Rotation: a rotated member aligns by its world AABB — after align-left its world AABB's left edge equals the frame's.
  • ALIGN-4 Mixed parents: members under different (including transformed) parents align to the shared world frame exactly; each member's commit is expressed in its own parent's coordinates.
  • ALIGN-5 Distribute: N≥3 required; after distribute, all adjacent gaps are equal and the outermost members have not moved.
  • ALIGN-6 In-flow exclusion: members positioned by auto-layout flow are not translated by align/distribute; an all-in-flow selection declines with no entry.
  • ALIGN-7 One entry per action; undo restores every member's prior position in one step.