Layout

Placement is a 2D problem, so layout solves it on the ground plane (plan space) and never projects; geometry projects and never places. LevelPlans::lay_out returns each level’s footprints, routes and stubs.

Components

Metrics

• Labels are measured in the bundled Inter faces, picked by CSS weight matching: 450 uses the 500 face.
• Layout sizes footprints and geometry places labels from the same measurements.

Placement fills each level, innermost first.

• A container is sized by its placed interior; a leaf by its labels, at least 72 × 66.
• Children with a position go exactly there; the rest are placed at least 18 units clear of them.
• Default: dagre ranks along plan x, so a chain of edges becomes a screen diagonal. Pin elements to control the shape, as examples/svugy/svugy.md does.
• grid, row, column: taffy packs the children in path order.

Routing

• An edge is routed in its home level between its true endpoints; for ranking, it joins the two children of that level that hold them.
• Each end attaches on the footprint side facing the other end.
• Badge edges get no route.

Stubs mark where edges leave a container: one boundary slot per external endpoint, on the side most of its edges cross, at their mean crossing point.

Layers

• Each layer is laid out on its own; a closed container is placed as the leaf it is in its layer.
• Pins hold in every layer, so a closed container leaves a gap where its open self would fit.

Code: crates/svugy/src/metrics/, crates/svugy/src/layout/.