Struct Present2Args

pub struct Present2Args {
    pub requested_presentation_time: Option<i64>,
    pub acquire_fences: Option<Vec<Event>>,
    pub release_fences: Option<Vec<Event>>,
    pub requested_prediction_span: Option<i64>,
    /* private fields */
}

Arguments passed into Present2(). Note that every argument is mandatory.

Fields

requested_presentation_time: Option<i64>

requested_presentation_time specifies the time on or after which the client would like the enqueued operations to take visible effect (light up pixels on the screen), expressed in nanoseconds in the CLOCK_MONOTONIC timebase.

Using a requested_presentation_time in the present or past (such as 0) schedules enqueued operations to take visible effect as soon as possible, during the next frame to be prepared. Requested presentation times must be monotonically increasing.

Using a requested_presentation_time in the future schedules the enqueued operations to take visible effect as closely as possible to or after the stated time, but no earlier.

Each rendered frame has a target presentation time. This is when Scenic aims to have the frame presented to the user. Before rendering a frame, the scene manager applies all enqueued operations associated with all prior calls to Present2 whose requested_presentation_time is on or before the frame’s target presentation time.

acquire_fences: Option<Vec<Event>>

Scenic will wait until all of a session’s acquire_fences are ready before it will execute the presented commands.

release_fences: Option<Vec<Event>>

release_fences is the list of events that will be signalled by Scenic when the following Present2 call’s acquire_fences has been signalled, and the updated session state has been fully committed: future frames will be rendered using this state, and all frames generated using previous session states have been fully-rendered and presented to the display.

requested_prediction_span: Option<i64>

requested_prediction_span is the amount of time into the future Scenic will provide predictions for. A span of 0 is guaranteed to provide at least one future time.

Trait Implementations

impl Debug for Present2Args

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

Formats the value using the given formatter.

impl Decode<Present2Args, DefaultFuchsiaResourceDialect> for Present2Args

fn new_empty() -> Self

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<'_, DefaultFuchsiaResourceDialect>, offset: usize, depth: Depth, ) -> Result<()>

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

impl Default for Present2Args

fn default() -> Present2Args

Returns the “default value” for a type.

impl Encode<Present2Args, DefaultFuchsiaResourceDialect> for &mut Present2Args

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

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

impl PartialEq for Present2Args

fn eq(&self, other: &Present2Args) -> 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 ResourceTypeMarker for Present2Args

type Borrowed<'a> = &'a mut Present2Args

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

fn take_or_borrow<'a>( value: &'a mut <Self as TypeMarker>::Owned, ) -> Self::Borrowed<'a>

Cheaply converts from &mut Self::Owned to Self::Borrowed. For HandleBased types this is “take” (it returns an owned handle and replaces value with Handle::invalid), and for all other types it is “borrow” (just converts from one reference to another).

impl TypeMarker for Present2Args

type Owned = Present2Args

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 Standalone<DefaultFuchsiaResourceDialect> for Present2Args

impl StructuralPartialEq for Present2Args