Struct FrameReport 

pub struct FrameReport {
    pub frame_index: u64,
    pub paint_damage: FrameDamage,
    pub present_damage: FrameDamage,
    pub accumulated_paint_damage: FrameDamage,
    pub accumulated_present_damage: FrameDamage,
    pub frames_since_reset: u32,
    pub reset_generation: u64,
    pub relayout_iterations: u32,
    pub dom_regenerations: u32,
    pub hit_depth_cap: bool,
    pub terminal_result: u8,
}

Per-frame observability record hung off LayoutWindow.

This is what makes damage + frame-work counters visible to an E2E assertion: CallbackInfo::get_layout_window().frame_report. The CPU backend writes paint_damage / present_damage / frame_index after every render_frame; the event loop writes the work counters.

The *_since_reset counters are STICKY: they are never cleared automatically (a per-tick reset would race the assertion that wants to read them). Use the reset_frame_counters debug op to zero them at a known point in a test.

Fields

frame_index: u64

Monotonic index of the last CPU-rendered frame.

paint_damage: FrameDamage

PAINT damage of the last frame — the pixels actually re-rasterised.

present_damage: FrameDamage

PRESENT damage of the last frame — the pixels that changed on screen (⊇ paint damage; a scroll memmoves a large region but paints a strip).

accumulated_paint_damage: FrameDamage

UNION of the paint damage of every frame since the last counter reset.

This is what a test must assert on: between the step that changed something and the assertion, the engine may render further (idle) frames whose damage is None, which would clobber paint_damage. The accumulated damage is stable across those.

accumulated_present_damage: FrameDamage

UNION of the present damage of every frame since the last counter reset.

frames_since_reset: u32

Frames rendered since the last counter reset.

reset_generation: u64

Generation of the last observed reset request (see request_frame_report_reset).

relayout_iterations: u32

Highest process_window_events recursion depth reached since the last counter reset. > 1 means the frame did not converge in one pass.

dom_regenerations: u32

Number of regenerate_layout() (i.e. layout_callback) runs since the last counter reset.

hit_depth_cap: bool

true if MAX_EVENT_RECURSION_DEPTH was ever hit since the last reset. Today the engine only log_warns on this; this flag is what lets a test turn an invalidation loop into a red assertion instead of a silent cap.

terminal_result: u8

The last terminal ProcessEventResult (as its u8 discriminant order).

Implementations

impl FrameReport

pub fn sync_generation(&mut self)

Zero the work counters + accumulated damage if a reset was requested. Called by every writer of the report before it writes.

pub fn reset_counters(&mut self)

Zero the sticky work counters + accumulated damage.

pub fn record_frame(&mut self, paint: FrameDamage, present: FrameDamage)

Record the damage of a freshly rendered frame: it becomes the last-frame damage AND is merged into the accumulated damage since the last reset.

Trait Implementations

impl Clone for FrameReport

fn clone(&self) -> FrameReport

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FrameReport

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

Formats the value using the given formatter.

impl Default for FrameReport

fn default() -> FrameReport

Returns the “default value” for a type.

impl PartialEq for FrameReport

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for FrameReport