Crate rux_layout 

Rux layout, milestones M1–M4.

A styled node tree fed through taffy (flexbox) to produce absolute paint items. Boxes come straight from taffy; text leaves are sized through a caller-supplied measure callback (so this crate stays free of any font dependency, the shell owns the text engine). See docs/04-architecture.md, Stage 4.

Structs

Access

The accessibility facts about one node: what it is, what it’s called, and what state it’s in. Attached during the build and carried through layout so the shell can publish a tree with real geometry.

AccessNode

One element exposed to assistive technology, with the geometry it ended up occupying. Emitted in document order, and only for nodes whose role is meaningful, a plain layout box contributes nothing.

BoxShadow

A single (outer) box-shadow. Offsets, blur and spread are logical px.

FocusItem

One keyboard-focusable element, in document (Tab) order. Carries the geometry (for the focus ring) plus how the shell should act on it.

FocusRegion

An absolutely-positioned focusable region for an <input>, carrying its r-model signal name.

Gradient

A CSS gradient reduced to what the painter needs: a shape and colour stops.

HitRegion

An absolutely-positioned tappable region, carrying its @tap handler source.

ImageContent

An image carried by a leaf node. src is resolved to a path the painter can open; the intrinsic size is filled in by the runtime (it reads the file’s header) and sizes the box when CSS gives no width/height.

Layout

The result of laying out a tree: paint items, hit regions, and focus regions, all in painter’s/topmost-last order.

Node

A node in the view tree: a style, optional text, children, and an optional @tap handler (raw handler source, run by the shell on tap).

Offset

How far a scroller’s content has travelled, in logical pixels. Positive moves the content up / left, i.e. y is “how far down the content we are”.

PaintImage

An image scaled to fill its laid-out box.

PaintRect

A resolved, absolutely-positioned box: an optional fill and an optional border, sharing one rounded-rect geometry.

PaintText

A resolved, absolutely-positioned text block.

PaintTick

A checkmark stroked inside its laid-out box.

Rgba

Straight RGBA in the 0..=1 range. Renderer-agnostic.

ScrollRegion

A scrollable box. id is its index in tree order, stable across rebuilds as long as the tree’s shape is, which is what the shell keys offsets by.

SelectRegion

An absolutely-positioned type="select", carrying its bound options so the shell can open a dropdown and write the chosen value back to model.

Sides

Per-side box-model lengths (padding / margin / border widths).

StateRegion

An absolutely-positioned box whose styling depends on pointer state (:hover / :active), carrying the tree path that identifies it to the builder. Emitted only for nodes some pointer-state rule could match, so a document with no such rules produces none.

Style

The style subset M-series understands (a stand-in for the CSS ComputedStyle).

TextContent

Text carried by a leaf node.

Enums

AccessRole

What an element is, for assistive technology. Deliberately a small enum owned by the layout rather than an accesskit type: the layout stays free of the platform a11y crate, and only the shell translates these.

Align

Cross-axis alignment (align-items).

Axis

How a node lays out its children. Defaults to Row to match CSS’s flex-direction initial value.

Background

A box background: a flat colour, a gradient, or an image.

Cursor

The mouse cursor shown while the pointer is over a box (cursor). Only the values the shell maps to a winit CursorIcon are modelled; the default is the arrow.

Display

CSS display. Defaults to Block (strict-CSS fidelity): flex layout, gap, and flex-direction only apply under Flex.

FocusKind

GradientKind

GridFlow

grid-auto-flow: how auto-placed items fill the implicit grid.

GridPlace

One endpoint of a grid-column / grid-row placement.

Justify

Main-axis distribution (justify-content).

Len

A CSS length. Percentages are stored as a fraction (0.0..=1.0); vh/vw hold the raw viewport-percentage number (e.g. 100vh → Vh(100.0)). rem is resolved to pixels at parse time.

Overflow

Overflow behaviour for content exceeding a box.

Paint

A drawable item in painter’s order (parents before children).

Position

position. Relative is the normal in-flow box (the default); Absolute takes the box out of flow and positions it by its inset against the nearest positioned ancestor.

TextAlign

Horizontal text alignment within a text box (text-align).

TextWrap

How a line may break when a word is wider than its box (overflow-wrap / word-break). CSS’s default lets a long word overflow rather than break.

Track

A grid track size (grid-template-columns/-rows).

TrackSide

One side of a minmax(), never itself a minmax. A Fr is only valid on the max side (a flex minimum is meaningless), and degrades to auto if used as a minimum.

Functions

layout

Lay out root into an avail_w x avail_h viewport, returning paint items and hit regions. Text leaves are sized via measure.

layout_scrolled

Lay out with the shell’s current scroll offsets (one per scrollable box, in tree order). A missing entry is 0.

Type Aliases

Corners

Corner radii in CSS order, top-left, top-right, bottom-right, bottom-left. A single border-radius fills all four; the per-corner longhands override.

Measure

Callback that measures a text block: (text, font_size, weight, wrap, max_width) -> (w, h). Measures a text node to (width, height) given an optional max width. Takes the whole TextContent so new text properties (family, spacing, style…) don’t each widen this signature.

Transform

A 2-D affine transform, as the six coefficients [a, b, c, d, e, f] (kurbo Affine order: x' = a·x + c·y + e, y' = b·x + d·y + f). Translations are in logical px; the origin is applied at paint time (CSS default: box centre).