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🎬 pixijs-actions  NPM version Minzipped Downloads Tests License

⚡ Powerful, high-performance animations for PixiJS

🔮 Simple, declarative API 🎬 Based on Cocos2d/SKActions
🚀 35+ built-in actions, 30+ timing modes 🔀 Reuseable, chainable & reversible
🍃 No dependencies & tree-shakeable ⌚ Full speed/pausing control
🤏 ~4.3kb minzipped ✨ Supports PixiJS 8+, 7+, 6.3+

Sample Usage

Create, configure, and run animations & actions.

// Define an action
const spinAndRemove = Action.sequence([
  Action.rotateByDegrees(360, 0.2).easeInOut(),
  Action.fadeOut(0.2).easeIn(),
  Action.removeFromParent(),
  Action.run(() => console.info('✨ done!'))
]);

// Run an action
mySprite.run(spinAndRemove);

Getting Started with PixiJS Actions

Everything you need to quickly build beautiful animations.

PixiJS Actions is based off the idiomatic and expressive SKActions API, extending Container to add first-class support for running and managing actions.

The core concepts are:

  1. Nodes: Any container (e.g. Container, Sprite, Graphics)
  2. Actions: Stateless, reusable recipes (e.g. animations, triggers, and more)
  3. TimingMode & speed: Controls for the speed & smoothness of actions and animations

Note

See Timing Modes and Manipulating Action Speed for more information.

Installation

Quick start guide.

1. Install the latest pixijs-actions package:

# npm
npm install pixijs-actions -D

# yarn
yarn add pixijs-actions --dev

2. Register the mixin & ticker:

import * as PIXI from 'pixi.js';
import { Action, registerPixiJSActionsMixin } from 'pixijs-actions';

// register container mixin
registerPixiJSActionsMixin(PIXI.Container);

// register `Action.tick(...)` with shared ticker
Ticker.shared.add(ticker => Action.tick(ticker.elapsedMS));

Tip

PixiJS 7 / 6.3+:

Ticker.shared.add(() => Action.tick(Ticker.shared.elapsedMS));
// or
Ticker.shared.add((dt) => Action.tick(dt));

Note

If not using a PixiJS ticker, then just put Action.tick(elapsedMs) in the appropriate equivalent place (i.e. your requestAnimationFrame() render loop).

3. Done!

✨ You are now ready to run your first action!

Running Actions

Running actions in your canvas.

// Hide me instantly!
mySprite.run(Action.hide(), () => {
  console.log('where did I go?');
});

Nodes are extended with a few new methods and properties to make it easy to interact with actions.

Property Description
speed A speed modifier applied to all actions executed by the node and its descendants. Defaults to 1.0.
isPaused A boolean value that determines whether actions on the node and its descendants are processed. Defaults to false.
Method Description
run(action) Run an action.
run(action, completion) Run an action with a completion handler.
runWithKey(action, withKey) Run an action, and store it so it can be retrieved later.
runAsPromise(action): Promise<void> Run an action as a promise.
action(forKey): Action | undefined Return an action associated with a specified key.
hasActions(): boolean Return a boolean indicating whether the node is executing actions.
removeAllActions(): void End and removes all actions from the node.
removeAction(forKey): void Remove an action associated with a specified key.

Running Identifiable Actions

// Repeat an action forever!
const spin = Action.repeatForever(Action.rotateBy(5, 1.0));
mySprite.runWithKey(spin, 'spinForever');

// Or remove it later.
mySprite.removeAction('spinForever');

Pausing All Actions

mySprite.isPaused = true;
// All actions will stop running.

Manipulating Action Speed

Speed can be manipulated on both actions and nodes.

const moveAction = Action.moveByX(10, 4.0);
moveAction.speed = 2.0;
// moveAction will now take only 2 seconds instead of 4.

const repeatAction = Action.repeat(moveAction, 5);
repeatAction.speed = 2.0;
// Each moveAction will only take 1 second, for a total of 5 seconds.

mySprite.run(moveAction);
mySprite.speed = 2.0;
// mySprite is running at 2x speed!
// The entire action should now take ~2.5 seconds.

mySprite.parent!.speed = 1 / 4;
// Now we've slowed down mySprite's parent.
// The entire action will now take ~10 seconds.

Note

Changes to nodes' speed will take effect immediately, however changes to an Action initializer's speed or timingMode will not affect any actions that have already begun running.

Action Initializers

Combine these initializers to create expressive animations and behaviors.

Most actions implement specific predefined animations that are ready to use. If your animation needs fall outside of the suite provided here, then you should implement a custom action (see Creating Custom Actions).

Action Description Reversible?
Chaining Actions
Action.group(actions) Run multiple actions in parallel. Yes
Action.sequence(actions) Run multiple actions sequentially. Yes
Action.repeat(action, count) Repeat an action a specified number of times. Yes
Action.repeatForever(action) Repeat an action indefinitely. Yes
Animating a Node's Position in a Linear Path
Action.moveBy(vector, duration) Move a node by a relative vector { x, y } (e.g. PIXI.Point). Yes
Action.moveBy(dx, dy, duration) Move a node by relative values. Yes
Action.moveByX(dx, duration) Move a node horizontally by a relative value. Yes
Action.moveByY(dy, duration) Move a node vertically by a relative value. Yes
Action.moveTo(position, duration) Move a node to a specified position { x, y } (e.g. PIXI.Point, PIXI.Container). *No
Action.moveTo(x, y, duration) Move a node to a specified position. *No
Action.moveToX(x, duration) Move a node to a specified horizontal position. *No
Action.moveToY(y, duration) Move a node to a specified vertical position. *No
Animating a Node's Position Along a Custom Path
Action.follow(path, duration) Move a node along a path, optionally orienting the node to the path. Yes
Action.followAtSpeed(path, speed) Move a node along a path at a specified speed, optionally orienting the node to the path. Yes
Animating the Rotation of a Node
Action.rotateBy(delta, duration) Rotate a node by a relative value (in radians). Yes
Action.rotateByDegrees(delta, duration) Rotate a node by a relative value (in degrees). Yes
Action.rotateTo(radians, duration) Rotate a node to a specified value (in radians). *No
Action.rotateToDegrees(degrees, duration) Rotate a node to a specified value (in degrees). *No
Animating the Scaling of a Node
Action.scaleBy(vector, duration) Scale a node by a relative vector { x, y } (e.g. PIXI.Point). Yes
Action.scaleBy(scale, duration) Scale a node by a relative value. Yes
Action.scaleBy(dx, dy, duration) Scale a node in each axis by relative values. Yes
Action.scaleByX(dx, duration) Scale a node horizontally by a relative value. Yes
Action.scaleByY(dy, duration) Scale a node vertically by a relative value. Yes
Action.scaleTo(size, duration) Scale a node to achieve a specified size { width, height } (e.g. PIXI.ISize, PIXI.Container). *No
Action.scaleTo(scale, duration) Scale a node to a specified value. *No
Action.scaleTo(x, y, duration) Scale a node in each axis to specified values. *No
Action.scaleToX(x, duration) Scale a node horizontally to a specified value. *No
Action.scaleToY(y, duration) Scale a node vertically to a specified value. *No
Animating the Transparency of a Node
Action.fadeIn(duration) Fade the alpha to 1.0. Yes
Action.fadeOut(duration) Fade the alpha to 0.0. Yes
Action.fadeAlphaBy(delta, duration) Fade the alpha by a relative value. Yes
Action.fadeAlphaTo(alpha, duration) Fade the alpha to a specified value. *No
Controlling a Node's Visibility
Action.unhide() Set a node's visible property to true. Yes
Action.hide() Set a node's visible property to false. Yes
Removing a Node from the Canvas
Action.removeFromParent() Remove a node from its parent. †Identical
Running Actions on Children
Action.runOnChild(nameOrLabel, action) Add an action to a child node. Yes
Delaying Actions
Action.waitForDuration(duration) Idle for a specified period of time. †Identical
Action.waitForDurationWithRange(duration, range) Idle for a randomized period of time. †Identical
Triggers and Custom Actions
Action.run(callback) Execute a block (i.e. trigger another action). †Identical
Action.customAction(duration, stepHandler) Execute a custom stepping function over the action duration. †Identical
Manipulating the Action Speed of a Node
Action.speedBy(delta, duration) Change how fast a node executes its actions by a relative value. Yes
Action.speedTo(speed, duration) Set how fast a node executes actions to a specified value. *No

Important

Reversing Actions

Every action initializer has a .reversed() method which will return a new action. Some actions are not reversible, and these cases are noted in the table above:

  • †Identical — The reversed action is identical to the original action.
  • *No — The reversed action will idle for the equivalent duration.

Action Chaining

Many actions can be joined together using Action.sequence(), Action.group(), Action.repeat() and Action.repeatForever() to quickly create complex animations:

import { Action } from 'pixijs-actions';

// Expand and contract smoothly over 2 seconds
const pulsate = Action.sequence([
  Action.scaleTo(1.5, 1.0).easeOut(),
  Action.scaleTo(1, 1.0).easeIn()
]);

// Follow a complex path (e.g. a bezier curve)
const path = [
  { x: 0, y: 0 },
  { x: 100, y: 0 },
  { x: 100, y: 100 },
  { x: 200, y: 200 }
];
const followPath = Action.follow(path, 5.0);

// Create a 10 second loop that goes back and forth
const moveBackAndForthWhilePulsating = Action.group([
  Action.repeat(pulsate, 5),
  Action.sequence([followPath, followPath.reversed()]),
]);

// ✨ Animate continuously
mySprite.run(Action.repeatForever(moveBackAndForthWhilePulsating));

Timing Modes

Every action has a timingMode which controls the timing curve of its execution.

The default timingMode for all actions is TimingMode.linear, which causes an animation to occur evenly over its duration.

You can customize the speed curve of actions in many ways:

// Default easings:
Action.fadeIn(0.3).easeIn();
Action.fadeIn(0.3).easeOut();
Action.fadeIn(0.3).easeInOut();

// Set a specific TimingMode:
Action.fadeIn(0.3).setTimingMode(TimingMode.easeInOutCubic);

// Set a custom timing function:
Action.fadeIn(0.3).setTimingMode(x => x * x);

Important

Timing Mutators: The .easeIn(), .easeOut(), .easeInOut(), setTimingMode(…), setSpeed(…) methods mutate the underlying action.

Built-in TimingMode Options

See the following table for default TimingMode options.

Pattern Ease In, Ease Out Ease In Ease Out Description
Linear linear - - Constant motion with no acceleration or deceleration.
Sine easeInOutSine easeInSine easeOutSine Gentle start and end, with accelerated motion in the middle.
Circular easeInOutCirc easeInCirc easeOutCirc Smooth start and end, faster acceleration in the middle, circular motion.
Cubic easeInOutCubic easeInCubic easeOutCubic Gradual acceleration and deceleration, smooth motion throughout.
Quadratic easeInOutQuad easeInQuad easeOutQuad Smooth acceleration and deceleration, starts and ends slowly, faster in the middle.
Quartic easeInOutQuart easeInQuart easeOutQuart Slower start and end, increased acceleration in the middle.
Quintic easeInOutQuint easeInQuint easeOutQuint Very gradual start and end, smoother acceleration in the middle.
Exponential easeInOutExpo easeInExpo easeOutExpo Very slow start, exponential acceleration, slow end.
Back easeInOutBack easeInBack easeOutBack Starts slowly, overshoots slightly, settles into final position.
Bounce easeInOutBounce easeInBounce easeOutBounce Bouncy effect at the start or end, with multiple rebounds.
Elastic easeInOutElastic easeInElastic easeOutElastic Stretchy motion with overshoot and multiple oscillations.

Default Timing Modes

The .easeIn(), .easeOut(), .easeInOut(), and .linear() mutator methods on Action instances will set the timing mode of that action to the global default timing mode for that curve type.

TimingMode mutator Global setting Default value
action.easeIn() Action.DefaultTimingModeEaseIn TimingMode.easeInSine
action.easeOut() Action.DefaultTimingModeEaseOut TimingMode.easeOutSine
action.easeInOut() Action.DefaultTimingModeEaseInOut TimingMode.easeInOutSine
action.linear() (n/a) TimingMode.linear

Global default timing modes can be set like so:

// set default
Action.DefaultTimingModeEaseIn = TimingMode.easeInQuad;

// apply
myNode.run(myAction.easeIn());

myAction.timingMode
// TimingMode.easeInQuad

Creating Custom Actions

Beyond combining chaining actions like sequence(), group(), repeat() and repeatForever(), you can provide code that implements your own action.

Composite Actions

Actions are stateless and reusable, so you can create complex animations once, and then run them on many nodes.

/** A nice gentle rock back and forth. */
const rockBackAndForth = Action.repeatForever(
  Action.group([
    Action.sequence([
      Action.moveByX(5, 0.33).easeOut(),
      Action.moveByX(-10, 0.34).easeInOut(),
      Action.moveByX(5, 0.33).easeIn(),
    ]),
    Action.sequence([
      Action.rotateByDegrees(-2, 0.33).easeOut(),
      Action.rotateByDegrees(4, 0.34).easeInOut(),
      Action.rotateByDegrees(-2, 0.33).easeIn(),
    ]),
  ])
);

// Run it over here
someSprite.run(rockBackAndForth);

// Run it somewhere else
someOtherContainer.run(rockBackAndForth);

You can combine these with dynamic actions for more variety:

const MyActions = {
  squash: (amount: number, duration: number = 0.3) => Action.sequence([
    Action.scaleTo(amount, 1 / amount, duration / 2).easeOut(),
    Action.scaleTo(1, duration / 2).easeIn()
  ]),
  stretch: (amount: number, duration: number = 0.3) => Action.sequence([
    Action.scaleTo(1 / amount, amount, duration / 2).easeOut(),
    Action.scaleTo(1, duration / 2).easeIn()
  ]),
  squashAndStretch: (amount: number, duration: number = 0.3) => Action.sequence([
    MyActions.squash(amount, duration / 2),
    MyActions.stretch(amount, duration / 2),
  ]),
};

// Small squish!
mySprite.run(MyActions.squashAndStretch(1.25));

// Big squish!
mySprite.run(MyActions.squashAndStretch(2.0));

Custom Action (Basic)

You can use the built-in Action.customAction(duration, stepHandler) to provide custom actions:

const rainbowColors = Action.customAction(5.0, (target, t, dt) => {
  // Calculate color based on time "t".
  const colorR = Math.sin(0.3 * t + 0) * 127 + 128;
  const colorG = Math.sin(0.3 * t + 2) * 127 + 128;
  const colorB = Math.sin(0.3 * t + 4) * 127 + 128;

  // Apply random color with time-based variation.
  target.tint = (colorR << 16) + (colorG << 8) + colorB;
});

// Start rainbow effect
mySprite.runWithKey(Action.repeatForever(rainbowColors), 'rainbow');

// Stop rainbow effect
mySprite.removeAction('rainbow');

Step functions:

  • target = The node the aciton is runnning against.
  • t = Progress of time from 0 to 1, which has been passed through the timingMode function.
  • dt = delta/change in t since last step. Use for relative actions.

Note: t can be outside of 0 and 1 in timing mode functions which overshoot, such as TimingMode.easeInOutBack.

This function will be called as many times as the renderer asks over the course of its duration.

Custom Action (with State)

Here is a practical example:

// Create a custom action that relies on
// state (radius, inital target position).
const makeOrbitAction = (
  radius: number,
  duration: number
): Action => {
  let startPos: PIXI.IPointData;

  return Action.customAction(duration, (target, t, td) => {
    if (!startPos) {
      // Capture on first run
      startPos = { x: target.x, y: target.y };
    }

    const angle = Math.PI * 2 * t;

    target.position.set(
      startPos.x + radius * Math.cos(angle),
      startPos.y + radius * Math.sin(angle)
    );
  });
};

// Run the custom action
mySprite.run(
  Action.repeatForever(makeOrbitAction(10, 15.0))
);

Contributions

PixiJS Actions was originally forked from srpatel's awesome pixi-actions library, but became a hard fork when we changed approach.

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