Struct RenderBudget 

pub struct RenderBudget { /* private fields */ }

Render time budget with graceful degradation.

Tracks elapsed time within a frame and manages degradation level to maintain responsive rendering under load.

Implementations

impl RenderBudget

pub fn new(total: Duration) -> Self

Create a new budget with the specified total time.

pub fn from_config(config: &FrameBudgetConfig) -> Self

Create a budget from configuration.

pub fn with_controller(self, config: BudgetControllerConfig) -> Self

Attach an adaptive budget controller to this render budget.

When a controller is attached, next_frame() feeds the measured frame duration to the controller and applies its degradation decisions instead of the simple threshold-based upgrade logic.

Example

use ftui_render::budget::{RenderBudget, BudgetControllerConfig};
use std::time::Duration;

let budget = RenderBudget::new(Duration::from_millis(16))
    .with_controller(BudgetControllerConfig::default());

pub fn total(&self) -> Duration

Get the total budget duration.

pub fn elapsed(&self) -> Duration

Get the elapsed time since budget started.

pub fn remaining(&self) -> Duration

Get the remaining time in the budget.

pub fn remaining_fraction(&self) -> f32

Get the remaining time as a fraction of total (0.0 to 1.0).

pub fn should_degrade(&self, estimated_cost: Duration) -> bool

Check if we should degrade given an estimated operation cost.

Returns true if the estimated cost exceeds remaining budget.

pub fn degrade(&mut self)

Degrade to the next level.

Logs a warning when degradation occurs.

pub fn degradation(&self) -> DegradationLevel

Get the current degradation level.

pub fn set_degradation(&mut self, level: DegradationLevel)

Set the degradation level directly.

Use with caution - prefer degrade() and upgrade() for gradual changes.

pub fn exhausted(&self) -> bool

Check if the budget is exhausted.

Returns true if no time remains OR if at SkipFrame level.

pub fn should_upgrade(&self) -> bool

Check if we should attempt to upgrade quality.

Returns true if more than upgrade_threshold of budget remains and we’re not already at full quality, and cooldown has passed.

pub fn upgrade(&mut self)

Upgrade to the previous (better quality) level.

Logs when upgrade occurs.

pub fn reset(&mut self)

Reset the budget for a new frame.

Keeps the current degradation level but resets timing.

pub fn next_frame(&mut self)

Reset the budget and attempt upgrade if conditions are met.

Call this at the start of each frame to enable recovery.

When an adaptive controller is attached (via with_controller), the measured frame duration is fed to the controller and its decision (degrade / upgrade / hold) is applied automatically. The simple threshold-based upgrade path is skipped in that case.

pub fn record_frame_time(&mut self, elapsed: Duration)

Record the measured render+present time for the last frame.

pub fn telemetry(&self) -> Option<BudgetTelemetry>

Get a telemetry snapshot from the adaptive controller, if attached.

Returns None if no controller is attached. This is allocation-free and safe to call every frame.

pub fn controller(&self) -> Option<&BudgetController>

Get a reference to the adaptive controller, if attached.

pub fn phase_budgets(&self) -> &PhaseBudgets

Get the phase budgets.

pub fn phase_has_budget(&self, phase: Phase) -> bool

Check if a specific phase has budget remaining.

pub fn phase_budget(&self, phase: Phase) -> Self

Create a sub-budget for a specific phase.

The sub-budget shares the same start time but has a phase-specific total.

Trait Implementations

impl Clone for RenderBudget

fn clone(&self) -> RenderBudget

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RenderBudget

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

Formats the value using the given formatter.