tone
Version:
A Web Audio framework for making interactive music in the browser.
79 lines • 2.51 kB
JavaScript
import { Timeline } from "./Timeline.js";
import { assertRange } from "./Debug.js";
/**
* A Timeline State. Provides the methods: `setStateAtTime("state", time)` and `getValueAtTime(time)`
* @param initial The initial state of the StateTimeline. Defaults to `undefined`
* @internal
*/
export class StateTimeline extends Timeline {
constructor(initial = "stopped") {
super();
this.name = "StateTimeline";
this._initial = initial;
this.setStateAtTime(this._initial, 0);
}
/**
* Returns the scheduled state scheduled before or at
* the given time.
* @param time The time to query.
* @return The name of the state input in setStateAtTime.
*/
getValueAtTime(time) {
const event = this.get(time);
if (event !== null) {
return event.state;
}
else {
return this._initial;
}
}
/**
* Add a state to the timeline.
* @param state The name of the state to set.
* @param time The time to query.
* @param options Any additional options that are needed in the timeline.
*/
setStateAtTime(state, time, options) {
assertRange(time, 0);
this.add(Object.assign({}, options, {
state,
time,
}));
return this;
}
/**
* Return the event before the time with the given state
* @param state The state to look for
* @param time When to check before
* @return The event with the given state before the time
*/
getLastState(state, time) {
// time = this.toSeconds(time);
const index = this._search(time);
for (let i = index; i >= 0; i--) {
const event = this._timeline[i];
if (event.state === state) {
return event;
}
}
}
/**
* Return the event after the time with the given state
* @param state The state to look for
* @param time When to check from
* @return The event with the given state after the time
*/
getNextState(state, time) {
// time = this.toSeconds(time);
const index = this._search(time);
if (index !== -1) {
for (let i = index; i < this._timeline.length; i++) {
const event = this._timeline[i];
if (event.state === state) {
return event;
}
}
}
}
}
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