Struct ViewDescriptor

pub struct ViewDescriptor {
    pub view_ref_koid: Option<u64>,
    pub layout: Option<Layout>,
    pub extent_in_context: Option<RotatableExtent>,
    pub extent_in_parent: Option<RotatableExtent>,
    pub children: Option<Vec<u32>>,
    /* private fields */
}

Data for a particular view: identifier, position, and children.

Fields

view_ref_koid: Option<u64>

This view’s fuchsia.ui.views.ViewRef koid.

layout: Option<Layout>

This view’s origin, logical size, pixel scale, and inset data, in the view’s own coordinate system.

Limitations. Data consistency between server and client depend on the specific graphics API. Some APIs provide weak consistency, where the server-side data (this data) and the client-side data (in the view’s UI client) are allowed to diverge for some time.

extent_in_context: Option<RotatableExtent>

This view’s extent, in the context view’s coordinate system. It does NOT describe the child view’s logical size.

This describes the “ground truth” position of this view within the context view, regardless of view tree depth, or specific layout state of intermediate views.

Limitations. It does NOT describe whether the view is “visible” (e.g., whether the view has opacity applied, or is not occluded by another view), and it does NOT describe whether the view is “hittable” (e.g., whether the view is positioned fully inside of every ancestor view’s bounding box).

extent_in_parent: Option<RotatableExtent>

The space occupied within the parent view’s coordinate system. It does NOT describe the child view’s logical size.

children: Option<Vec<u32>>

The list of child views, in the order known to the graphics API.

Each integer in this vector refers to the child’s position in the |views| or |incomplete| vector that the parent is in.

The identity, position, and size of each child view. Position and size are described by the extent of the child view within the parent view’s coordinate system.

The view tree topology is reliable. A child placed here is equivalent to the parent view receiving a “child view connected” signal.

Limitations. A child’s view boundary is described in the parent view’s coordinate system, which is subject to weak consistency (depending on the graphics API). That is, when a parent view has a change in size or metrics, the context view may observe a “jump” as the parent view incorporates those data. In such cases, a new ViewTreeSnapshot is issued to describe the change in position, relative to the context view.

Trait Implementations

impl Clone for ViewDescriptor

fn clone(&self) -> ViewDescriptor

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ViewDescriptor

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<D> Decode<ViewDescriptor, D> for ViewDescriptor

where D: ResourceDialect,

fn new_empty() -> ViewDescriptor

Creates a valid instance of Self. The specific value does not matter, since it will be overwritten by decode.

unsafe fn decode( &mut self, decoder: &mut Decoder<'_, D>, offset: usize, depth: Depth, ) -> Result<(), Error>

Decodes an object of type T from the decoder’s buffers into self.

impl Default for ViewDescriptor

fn default() -> ViewDescriptor

Returns the “default value” for a type.

impl<D> Encode<ViewDescriptor, D> for &ViewDescriptor

where D: ResourceDialect,

unsafe fn encode( self, encoder: &mut Encoder<'_, D>, offset: usize, depth: Depth, ) -> Result<(), Error>

Encodes the object into the encoder’s buffers. Any handles stored in the object are swapped for Handle::INVALID.

impl PartialEq for ViewDescriptor

fn eq(&self, other: &ViewDescriptor) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl TypeMarker for ViewDescriptor

type Owned = ViewDescriptor

The owned Rust type which this FIDL type decodes into.

fn inline_align(_context: Context) -> usize

Returns the minimum required alignment of the inline portion of the encoded object. It must be a (nonzero) power of two.

fn inline_size(_context: Context) -> usize

Returns the size of the inline portion of the encoded object, including padding for alignment. Must be a multiple of inline_align.

fn encode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and encoding requires no validation. When true, we can optimize encoding arrays and vectors of Self::Owned to a single memcpy.

fn decode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and decoding requires no validation. When true, we can optimize decoding arrays and vectors of Self::Owned to a single memcpy.

impl ValueTypeMarker for ViewDescriptor

type Borrowed<'a> = &'a ViewDescriptor

The Rust type to use for encoding. This is a particular Encode<Self> type cheaply obtainable from &Self::Owned. There are three cases:

fn borrow( value: &<ViewDescriptor as TypeMarker>::Owned, ) -> <ViewDescriptor as ValueTypeMarker>::Borrowed<'_>

Cheaply converts from &Self::Owned to Self::Borrowed.

impl Persistable for ViewDescriptor

impl StructuralPartialEq for ViewDescriptor