Struct DamageTracker 

pub struct DamageTracker { /* private fields */ }

Accumulates dirty rectangles across a frame and emits a merged redraw region at frame time.

Two orthogonal states:

• full-damage flag — set by mark_full when something invalidates the whole viewport. In this state the individual rect list is ignored.
• pending rects — added via add.

merged unions all pending rects into one; rects exposes the raw list for callers that want to implement their own coalescing strategy (conservative — keep small rects, aggressive — union everything, or threshold — fall back to full viewport when dirty area exceeds N% of total).

Implementations

impl DamageTracker

pub const fn new() -> Self

New empty tracker. Initial state: no damage.

pub const fn with_full_damage() -> Self

New tracker pre-flagged for full-viewport damage. Useful on startup or after a window resize.

pub fn add(&mut self, rect: DamageRect)

Add a dirty rectangle. Ignored if the full-damage flag is set.

pub fn mark_full(&mut self)

Mark the entire viewport as dirty; clears individual rects.

pub fn clear(&mut self)

Reset to no-damage state.

pub fn is_full(&self) -> bool

Whether the full-damage flag is set.

pub fn has_damage(&self) -> bool

Whether there is anything to redraw (full flag or any rects).

pub fn rects(&self) -> &[DamageRect]

Immutable view of the pending rects (empty if none or if full flag is set — check is_full first).

pub fn merged(&self) -> Option<DamageRect>

Union of all pending rects, or None if the full flag is set or there are no rects.

When the full flag is set, returns None — the caller should consult is_full and render the whole viewport. The library doesn’t know the viewport size so it cannot produce the full-viewport rect on your behalf.

pub fn area_upper_bound(&self) -> f32

Sum of the individual rect areas. Over-counts overlap — if rects A and B overlap by area X, the returned value is area(A) + area(B) which double-counts X.

Use this as a cheap upper bound when deciding whether to fall back to full viewport redraw via a threshold.

pub fn len(&self) -> usize

Number of pending rects (zero if full flag is set).

pub fn is_empty(&self) -> bool

Whether the pending rect list is empty. Note: can return true while is_full also returns true — use has_damage for “anything to redraw”.

Trait Implementations

impl Clone for DamageTracker

fn clone(&self) -> DamageTracker

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DamageTracker

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

Formats the value using the given formatter.

impl Default for DamageTracker

fn default() -> DamageTracker

Returns the “default value” for a type.