Scene Builders

Scene<Msg> nodes and modifiers. Every builder takes a stable id (impl Into<NodeId>); see Scene Algebra for the design rationale.

Structure

Builder	Layout
`text(id, content)`	leaf text node
`row(id, children)`	horizontal flow
`column(id, children)`	vertical flow
`stack(id, children)`	same cell, back-to-front
`overlay(id, children)`	floating above the base

Wrappers

Builder	Effect
`padding(id, Padding, child)`	inset space
`border(id, child)`	drawn border
`sized(id, SizeConstraint, child)`	width/height constraint
`viewport(id, child)`	clip to bounds
`scroll(id, ScrollOffset, child)`	scrolled content
`align(id, Anchor, child)`	anchor within available space
`annotated(id, label, child)`	attach an annotation label

Focus

Builder	Effect
`focus_scope(id, name, child)`	named scope, default policy
`focus_scope_with_policy(id, name, policy, child)`	`Wrap` / `Trap` / `Local` / `Passthrough`

Modifiers (chainable)

#![allow(unused)]
fn main() {
.with_style(Style)            // Color/Emphasis
.with_role(Role)              // semantic role (Button, etc.)
.with_annotation(Annotation)  // presence/cursor overlays, labels
.focusable()                  // enter the Tab order
.disabled()                   // skip focus + activation
.on_activate(msg)             // Enter/click → msg
.map_msg(&fn)                 // Msg → ParentMsg translation
}

Supporting types

Style, Color, Emphasis · Role · Annotation · Padding · SizeConstraint / Size · ScrollOffset · Anchor · NodeId

All are plain data — scenes are cheap to construct per projection, and the id-keyed diff keeps commits cheap when ids are stable.