Raxol.Core.Accessibility.Projection (Raxol Core v2.6.0)

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Projects a declaration Element tree into an accessibility tree.

The accessibility tree is a role/label/state descriptor tree that Surfaces (MCP, Browser) serialize to drive assistive technology. It is derived from the same Element tree that Raxol.MCP.TreeWalker walks (the view/1 output synced to the Dispatcher), so a node here carries the discrete Component props.

For each Element the projection either calls the Component's Raxol.Core.Accessibility.Provider.a11y_node/1 (for the ~15 Components that implement it) or falls back to a default extraction driven by Raxol.Core.Accessibility.Roles. The projection is total: it never raises for any input, defaulting unknown types to :generic and rescuing a Provider that itself raises.

Dependency direction

This lives in raxol_core (which Browser and MCP both depend on, but which does NOT depend on main raxol). The type -> module map names Component modules in main raxol; they are resolved at runtime only when loaded, guarded by Provider.provider?/1, so raxol_core stays free of a main-raxol dependency.

Summary

Types

accessibility_node()

Functions

by_id(tree, opts \\ [])

Flat id -> accessibility_node map for Surfaces that key ARIA by Element id.

descriptor(node, opts \\ [])

Projects a single Element's own descriptor -- role/label/state/value/live?/id -- WITHOUT recursing its children (children is always []).

project(tree, opts \\ [])

Projects an Element (or list of Elements) into an accessibility node (or list).

Types

accessibility_node()

@type accessibility_node() :: %{
  role: atom(),
  label: String.t() | nil,
  state: %{optional(atom()) => boolean() | atom()},
  value: term() | nil,
  children: [accessibility_node()],
  live?: boolean(),
  id: String.t() | nil
}

Functions

by_id(tree, opts \\ [])

@spec by_id(
  map() | [map()] | nil,
  keyword()
) :: %{optional(String.t()) => accessibility_node()}

Flat id -> accessibility_node map for Surfaces that key ARIA by Element id.

Only nodes with a non-empty binary id are included.

descriptor(node, opts \\ [])

@spec descriptor(
  map(),
  keyword()
) :: accessibility_node() | nil

Projects a single Element's own descriptor -- role/label/state/value/live?/id -- WITHOUT recursing its children (children is always []).

For Surfaces that walk the Element tree themselves (e.g. MCP StructuredScreenshot) and only need per-node a11y fields folded in.

project(tree, opts \\ [])

@spec project(
  map() | [map()] | nil,
  keyword()
) :: accessibility_node() | [accessibility_node()] | nil

Projects an Element (or list of Elements) into an accessibility node (or list).

Options

  • :type_map - override the declaration-type -> Component-module map (defaults to the built-in 15-Component map). Mirrors Raxol.MCP.TreeWalker's context.type_map.