Class AccessibilityTreeSnapshot

Namespace: Forma

Assembly: Forma.dll

A flat, ordered, serializable projection of the accessibility tree at one instant.

Flat rather than nested because every consumer wants it that way: a diff needs to find a node by id without a search, a transport wants no recursion, and a locator wants to filter. Order is depth-first in draw order, so reading the list top to bottom matches what a person sees.

public sealed class AccessibilityTreeSnapshot

Inheritance: object

AccessibilityTreeSnapshot

Inherited Members: object.GetType()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Properties

FocusedId

Id of the focused node, or 0 when nothing has focus.

public int FocusedId { get; }

Property Value

int

IsModalActive

Whether a modal popup was up. When it is, the snapshot contains only that popup's subtree, matching what input does — anything behind a modal is unreachable, so reporting it would invite a consumer to act on something a person could not.

public bool IsModalActive { get; }

Property Value

bool

Nodes

Every visible node, depth-first in draw order.

public IReadOnlyList<AccessibilityNode> Nodes { get; }

Property Value

IReadOnlyList<AccessibilityNode>

Methods

ToLayoutText()

The same tree as ToText() with each node's bounds, for working out why something is laid out the way it is.

public string ToLayoutText()

Returns

string

Remarks

Deliberately not what ToText() produces, and deliberately not for goldens: bounds churn with window size and would make every unrelated change look like a regression. This is the other half of that trade -- a view you reach for when a control is the wrong size and you need to know which ancestor decided that, which is the question a golden tree cannot answer.

ToString()

A short summary for logs; use ToText() for the tree itself.

public override string ToString()

Returns

string

ToText()

Indented role "name" lines, one per node. Stable enough to commit as a golden file: bounds and ids are deliberately omitted, because they churn with window size and allocation order and would make every unrelated change look like a regression.

public string ToText()

Returns

string

TryGetNode(int, out AccessibilityNode)

Finds a node by id without scanning, which is what makes diffing cheap.

public bool TryGetNode(int id, out AccessibilityNode node)

Parameters

id int
node AccessibilityNode

Returns

bool