Crate alpha2_eval 

Pure, deterministic timeline evaluation.

Structs

ActiveAudioClip

One audio clip overlapping an evaluated timeline span.

ActiveCaption

The cue one caption track shows at a timestamp.

ActiveClip

A visible or audible clip mapped to its source timestamp.

ActiveComposition

A clip’s composition at one timeline timestamp.

ActiveEffect

One effect invocation at one timestamp: timeline time for a timeline transition, composition time for a composition step.

ActiveIndex

A precomputed interval index for a validated project snapshot.

ActiveTransition

A transition evaluated at one timeline timestamp.

AudioSpan

The clips of one span, as evaluate_audio reports them, held in an AudioSpanScratch and read back without copying.

AudioSpanDesc

Audio activity over one half-open timeline span.

AudioSpanScratch

Reusable working memory for evaluate_audio_in.

CompositionPlan

A composition’s output, drawn by steps in dependency order.

EffectParamValue

One effect parameter’s value at a timeline timestamp.

EvaluatedLayout

A layout tree with every value sampled.

EvaluatedNode

One box, its values sampled. Lengths are fractions of the picture’s shorter side.

EvaluatedText

A text node’s sampled text and the style it inherits.

EvaluatedVisual

Visual properties evaluated at one timeline timestamp.

FrameDesc

A timestamp-specific composition description with no GPU handles.

FrameNeed

A source-frame request emitted for host prefetch and decode scheduling.

LayoutPlan

A layout tree, evaluated once when it does not animate.

NodeLayout

A box’s sampled box-model, flex and grid values. Lengths are fractions or percents, never pixels.

NodePaint

What a box draws under its content.

NodeVisual

How a box and its subtree are drawn after layout.

ShapesPlan

A content tree, its parts that do not animate evaluated once.

Sides

A length on each side of a box, as a fraction of the picture’s shorter side.

Step

One node of a composition, with its inputs resolved to earlier steps.

StepLayer

One layer of a StepOp::Merge.

Enums

EvalError

An evaluator failure.

GeneratorPlan

A generator’s tree, planned once: what a shapes or layout generator evaluates each frame from. Other generators need none.

NodeContent

A box’s content.

PlanError

Why a composition’s output cannot be drawn.

StepOp

The operation of a Step. Inputs are indices of earlier steps.

Constants

MAX_PLAN_BYTES

Most bytes the compiled composition plans of one project hold together, as Steps estimate them: each step, its node path, and the heap its settings use (keyframes, parameter and resource names, masks, layers, gradient stops). A project’s plans are those of every composition a clip or composition source shows; past this, none of them is drawn (PlanError::TooLarge). The steps are what validation counts, at most MAX_INLINED_NODES; this bounds how large each may be, which inlining multiplies.

Functions

evaluate

Evaluates visual and audio clip descriptions at one timeline timestamp.

evaluate_audio

Evaluates every audible clip overlapping a half-open timeline span.

evaluate_audio_in

Evaluates the same clips as evaluate_audio into reusable memory.

evaluate_geometry

A geometry at time: a mask’s outline, or a content tree’s.

evaluate_item

One item at time. Opacities, trims, and roundness are clamped to 0..=1 and lengths to zero or more, as an overshooting curve could carry them past.

evaluate_items

A whole content tree at time, without a plan.

frame_needs

Describes all source frames needed at a timestamp.

picture_source_time

The source instant a clip’s picture shows at timeline time: its time map read with the reverse and ping-pong mirror of one project frame at frame_rate, exactly as evaluation draws it.

plan_composition

Compiles composition’s output into steps, as a clip’s composition: its clip nodes draw the clip’s picture. compositions resolves group nodes and sources media nodes, which may name generated or composition sources.

plan_source_composition

Compiles composition as a composition source draws it: like plan_composition, but a clip node or group input is an error, since no clip or group node feeds it.

sample_effect_param

Samples one effect parameter with the project’s keyframe semantics.

sample_hold

Samples a value that does not interpolate: the last keyframe at or before time, else the first.

sample_insets

Samples per-side lengths, each side as [sample_size] samples one.

sample_length

Samples a layout length. Validation makes every keyframe one kind (a plan’s lengths are fractions or percents); were they not, the left keyframe’s kind is kept.

sample_paint

Samples an animated paint. Colors interpolate premultiplied, as effect colors do, and gradient points, radii, angles, and stop offsets numerically; offsets are then kept in order within 0..=1 and a radius positive, as an overshooting curve could carry them past. Validation keeps the keyframes alike in kind, stops, and spread; were they not, the left keyframe’s paint is held.

sample_path

Samples an animated path: every point and tangent moves along a straight line between keyframes, in f64. Validation keeps the keyframes alike in structure; were they not, the left keyframe’s path is held.

sample_point

Samples a position that may move along spatial curves.

sample_scalar

Samples one animated scalar with the project’s keyframe semantics.

sample_vec2

Samples one animated two-dimensional value with the project’s keyframe semantics; see sample_scalar. A position that may follow spatial curves is sampled with sample_point.

sample_visual

Evaluates visual properties at a timestamp: a clip’s at timeline time, a transform node’s at composition time. aspect is the width over the height of the space the position is normalized in (the canvas), in which a position moving along a spatial curve is measured.