Animations
Overview
Ionic Animations is a tool that enables developers to create complex animations in a platform-agnostic manner, without requiring a specific framework or an Ionic app.
Creating efficient animations can be challenging, as developers are limited by the available libraries and hardware resources of the device. Moreover, many animation libraries use a JavaScript-driven approach, which can reduce the scalability of animations and use up CPU time.
Ionic Animations, on the other hand, uses the Web Animations API, which offloads all the computation and running of animations to the browser. This approach allows the browser to optimize the animations and ensure their smooth execution. In cases where Web Animations are not supported, Ionic Animations will fall back to CSS Animations, which should have a negligible difference in performance.
Installation
- JavaScript
- TypeScript
- Angular
- React
- Vue
Developers using Ionic Core and JavaScript should install the latest version of @ionic/core
.
import { createAnimation } from 'https://cdn.jsdelivr.net/npm/@ionic/core@latest/dist/esm/index.mjs';
...
const animation = createAnimation()
.addElement(myElementRef)
.duration(1000)
.fromTo('opacity', '1', '0.5');
}
Developers using Ionic Core and TypeScript should install the latest version of @ionic/core
.
import { createAnimation, Animation } from '@ionic/core';
...
const animation: Animation = createAnimation('')
.addElement(myElementRef)
.duration(1000)
.fromTo('opacity', '1', '0.5');
}
Developers using Angular should install the latest version of @ionic/angular
. Animations can be created via the AnimationController
dependency injection.
import { Animation, AnimationController } from '@ionic/angular';
...
constructor(private animationCtrl: AnimationController) {
const animation: Animation = this.animationCtrl.create()
.addElement(myElementRef)
.duration(1000)
.fromTo('opacity', '1', '0.5');
}
Developers using React should install the latest version of @ionic/react
. React wrappers are in beta. Please report any issues on GitHub!
import { CreateAnimation, Animation } from '@ionic/react';
...
<CreateAnimation
duration={1000}
fromTo={{
property: 'opacity',
fromValue: '1',
toValue: '0.5'
}}
>
...
</CreateAnimation>
Developers using Ionic Vue should install the latest version of @ionic/vue
.
import { createAnimation } from '@ionic/vue';
import { ref } from 'vue';
...
const myElementRef = ref();
...
const animation = createAnimation()
.addElement(myElementRef.value)
.duration(1000)
.fromTo('opacity', '1', '0.5');
}
Basic Animations
In the example below, an animation that changes the opacity on the ion-card
element and moves it from left to right along the X axis has been created. This animation will run an infinite number of times, and each iteration of the animation will last 1500ms.
By default, all Ionic Animations are paused until the play
method is called.
Keyframe Animations
Ionic Animations allows you to control the intermediate steps in an animation using keyframes. Any valid CSS property can be used here, and you can even use CSS Variables as values.
Hyphenated CSS properties should be written using camel case when writing keyframes. For example, border-radius
should be written as borderRadius
. This also applies to the fromTo()
, from(),
and to()
methods.
In the example above, the card element will transition from its initial width, to a width defined by the --width
variable, and then transition on to the final width.
Each keyframe object contains an offset
property. offset
is a value between 0 and 1 that defines the keyframe step. Offset values must go in ascending order and cannot repeat.
Grouped Animations
Multiple elements can be animated at the same time and controlled via a single parent animation object. Child animations inherit properties such as duration, easing, and iterations unless otherwise specified. A parent animation's onFinish
callback will not be called until all child animations have completed.
This example shows 3 child animations controlled by a single parent animation. Animations cardA
and cardB
inherit the parent animation's duration of 2000ms, but animation cardC
has a duration of 5000ms since it was explicitly set.
Before and After Hooks
Ionic Animations provides hooks that let you alter an element before an animation runs and after an animation completes. These hooks can be used to perform DOM reads and writes as well as add or remove classes and inline styles.
This example sets an inline filter which inverts the background color of the card by 75%
prior to the animation starting. Once the animation finishes, the box shadow on the element is set to rgba(255, 0, 50, 0.4) 0px 4px 16px 6px
, a red glow, and the inline filter is cleared. The animation must be stopped in order to remove the box shadow and play it with the filter again.
See Methods for a complete list of hooks.
Chained Animations
Animations can be chained to run one after the other. The play
method returns a Promise that resolves when the animation has completed.
Gesture Animations
Ionic Animations gives developers the ability to create powerful gesture-based animations by integrating seamlessly with Ionic Gestures.
In the following example we are creating a track along which we can drag the card element. Our animation
object will take care of moving the card element either left or right, and our gesture
object will instruct the animation
object which direction to move in.
Preference-Based Animations
Developers can also tailor their animations to user preferences such as prefers-reduced-motion
and prefers-color-scheme
using CSS Variables.
This method works in all supported browsers when creating animations for the first time. Most browsers are also capable of dynamically updating keyframe animations as the CSS Variables change.
Safari does not currently support dynamically updating keyframe animations. For developers who need this kind of support in Safari, they can use MediaQueryList.addListener().
Overriding Ionic Component Animations
Certain Ionic components allow developers to provide custom animations. All animations are provided as either properties on the component or are set via a global config.
Modals
Performance Considerations
CSS and Web Animations are usually handled on the compositor thread. This is different than the main thread where layout, painting, styling, and your JavaScript is executed. It is recommended that you prefer using properties that can be handled on the compositor thread for optimal animation performance.
Animating properties such as height
and width
cause additional layouts and paints which can cause jank and degrade animation performance. On the other hand, animating properties such as transform
and opacity
are highly optimizable by the browser and typically do not cause much jank.
For information on which CSS properties cause layouts or paints to occur, see CSS Triggers.
Debugging
For debugging animations in Chrome, there is a great blog post about inspecting animations using the Chrome DevTools: https://developers.google.com/web/tools/chrome-devtools/inspect-styles/animations.
It is also recommended to assign unique identifiers to your animations. These identifiers will show up in the Animations inspector in Chrome and should make it easier to debug:
/**
* The animation for the .square element should
* show "my-animation-identifier" in Chrome DevTools.
*/
const animation = createAnimation('my-animation-identifier')
.addElement(document.querySelector('.square'))
.duration(1000)
.fromTo('opacity', '1', '0');
API
This section provides a list of all the methods and properties available on the Animation
class.
Interfaces
AnimationDirection
type AnimationDirection = 'normal' | 'reverse' | 'alternate' | 'alternate-reverse';
AnimationFill
type AnimationFill = 'auto' | 'none' | 'forwards' | 'backwards' | 'both';
AnimationBuilder
type AnimationBuilder = (baseEl: any, opts?: any) => Animation;
opts
are additional options that are specific to the custom animation. For example, the sheet modal enter animation includes information for the current breakpoint.
AnimationCallbackOptions
interface AnimationCallbackOptions {
/**
* If true, the associated callback will only be fired once.
*/
oneTimeCallback: boolean;
}
AnimationPlayOptions
interface AnimationPlayOptions {
/**
* If true, the animation will play synchronously.
* This is the equivalent of running the animation
* with a duration of 0ms.
*/
sync: boolean;
}
Properties
Name | Description |
---|---|
childAnimations: Animation[] | All child animations of a given parent animation. |
elements: HTMLElement[] | All elements attached to an animation. |
parentAnimation?: Animation | The parent animation of a given animation object. |
Methods
Name | Description |
---|---|
addAnimation(animationToAdd: Animation \| Animation[]): Animation | Group one or more animations together to be controlled by a parent animation. |
addElement(el: Element \| Element[] \| Node \| Node[] \| NodeList): Animation | Add one or more elements to the animation. |
afterAddClass(className: string \| string[]): Animation | Add a class or array of classes to be added to all elements in an animation after the animation ends. |
afterAddRead(readFn: (): void): Animation | Add a function that performs a DOM read to be run after the animation ends. |
afterAddWrite(writeFn: (): void): Animation | Add a function that performs a DOM write to be run after the animation ends. |
afterClearStyles(propertyNames: string[]): Animation | Add an array of property names to be cleared from the inline styles on all elements in an animation after the animation ends. |
afterRemoveClass(className: string \| string[]): Animation | Add a class or an array of classes to be removed from all elements in an animation after the animation ends. |
afterStyles(styles: { [property: string]: any }): Animation | Add an object of styles to be applied to all elements in an animation after the animation ends. |
beforeAddClass(className: string \| string[]): Animation | Add a class or array of classes to be added to all elements in an animation before the animation starts. |
beforeAddRead(readFn: (): void): Animation | Add a function that performs a DOM read to be run before the animation starts. |
beforeAddWrite(writeFn: (): void): Animation | Add a function that performs a DOM write to be run before the animation starts. |
beforeClearStyles(propertyNames: string[]): Animation | Add an array of property names to be cleared from the inline styles on all elements in an animation before the animation starts. |
beforeRemoveClass(className: string \| string[]): Animation | Add a class or an array of classes to be removed from all elements in an animation before the animation starts. |
beforeStyles(styles: { [property: string]: any }): Animation | Add an object of styles to be applied to all elements in an animation before the animation starts. |
direction(direction?: AnimationDirection): Animation | Set the direction the animation should play in. |
delay(delay?: number): Animation | Set the delay for the start of the animation in milliseconds. |
destroy(clearStyleSheets?: boolean): Animation | Destroy the animation and clear all elements, child animations, and keyframes. |
duration(duration?: number): Animation | Set the duration of the animation in milliseconds. |
easing(easing?: string): Animation | Set the easing of the animation in milliseconds. See Easing Effects for a list of accepted easing values. |
from(property: string, value: any): Animation | Set the start styles of the animation. |
fromTo(property: string, fromValue: any, toValue: any): Animation | Set the start and end styles of the animation. |
fill(fill?: AnimationFill): Animation | Set how the animation applies styles to its elements before and after the animation's execution. |
iterations(iterations: number): Animation | Set the number of times the animation cycle should be played before stopping. |
keyframes(keyframes: any[]): Animation | Set the keyframes for an animation. |
onFinish(callback: (didComplete: boolean, animation: Animation): void, opts?: AnimationCallbackOptions): Animation | Add a callback to be run upon the animation ending. |
pause(): Animation | Pause the animation. |
play(opts?: AnimationPlayOptions): Promise<void> | Play the animation. |
progressEnd(playTo?: 0 \| 1, step: number, dur?: number): Animation | Stop seeking through an animation. |
progressStart(forceLinearEasing?: boolean, step?: number): Animation | Begin seeking through an animation. |
progressStep(step: number): Animation | Seek through an animation. |
stop(): Animation | Stop the animation and reset all elements to their initial state. |
to(property: string, value: any): Animation | Set the end styles of the animation. |