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Animation Progress and requestAnimationFrame

The Web Animation API doesn’t allow for keeping track of the progress in a clean way, so, we are forced to use requestAnimationFrame to check the current progress of an animation, however, doing, so, can actually decrease framerates, so, I built a system to call requestAnimationFrame less often.

@okikio/animate stores running Animate instances in a Set stored in the Animate class’s static RUNNING property. The RUNNING property only stores Animate instances that have registered “update” event listeners.

When an Animate instance is played, it gets added to the RUNNING Set, Animate.requestFrame() is then called and a single requestAnimationFrame runs for all Animate instances in the RUNNING set. If after a couple frames a Animate instance doesn’t have an attached “update” event listener it is automatically removed from the RUNNING Set.

Note: Animate instances that are finished are also auto-removed, and if there are no Animate instances in the RUNNING Set the requestAnimationFrame is stopped.

For you to better understand, check this out (this is meant for visiualization, avoid directly interacting with these API’s),

import ASTRO_ESCAPED_LEFT_CURLY_BRACKET Animate } from "@okikio/"
Animate.RUNNING = new Set();

let instance = new Animate(ASTRO_ESCAPED_LEFT_CURLY_BRACKET /* .... */ });
instance.on("update", () => console.log("It works"));

// If there are "update" event listener
if (instance.emitter.getEvent("update").length > 0) ASTRO_ESCAPED_LEFT_CURLY_BRACKET
    if (Animate.animationFrame == null) Animate.requestFrame();

If you add an “update” event listener to an Animate instance, the Animate instance is added to the RUNNING Set, and if a requestAnimationFrame isn’t already running it will request a new one.

By default requestAnimationFrame is now throttled to match a maximum frame rate of 60 fps (frames per second). You can change the frame rate by setting Animate.FRAME_RATE to your preferred frame rate.

Note: the frame rate affects tweenAttr, as it uses the “update” event to animation attributes.

Animate.FRAME_RATE = 30; // 30 fps