Struct FrameDelayer 

pub(crate) struct FrameDelayer {
    image_epochs: FxHashMap<ImageKey, Epoch>,
    pending_canvas_images: FxHashMap<ImageKey, Epoch>,
    pub(crate) pending_frame: bool,
    waiting_pipelines: FxHashSet<PipelineId>,
}

A struct that is reponsible for delaying frame requests until all new canvas images for a particular “update the rendering” call in the ScriptThread have been sent to WebRender.

These images may be updated in WebRender asynchronously in the canvas task. A frame is then requested if:

• The renderer has received a GenerateFrame message from a ScriptThread.
• All pending image updates have finished and have been noted in the FrameDelayer.

Fields

image_epochs: FxHashMap<ImageKey, Epoch>

The latest Epoch of canvas images that have been sent to WebRender. Note that this only records the Epochs for canvases and only ones that are involved in “update the rendering”.

pending_canvas_images: FxHashMap<ImageKey, Epoch>

A map of all pending canvas images

pending_frame: bool

Whether or not we have a pending frame.

waiting_pipelines: FxHashSet<PipelineId>

A list of pipelines that should be notified when we are no longer waiting for canvas images.

Implementations

impl FrameDelayer

pub(crate) fn delete_image(&mut self, image_key: ImageKey)

pub(crate) fn update_image(&mut self, image_key: ImageKey, epoch: Epoch)

pub(crate) fn add_delay( &mut self, pipeline_id: PipelineId, canvas_epoch: Epoch, image_keys: Vec<ImageKey>, )

pub(crate) fn needs_new_frame(&self) -> bool

pub(crate) fn set_pending_frame(&mut self, value: bool)

pub(crate) fn take_waiting_pipelines(&mut self) -> Vec<PipelineId>

Trait Implementations

impl Default for FrameDelayer

fn default() -> FrameDelayer

Returns the “default value” for a type.