shoelace/src/components/animated-image/animated-image.ts

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3.7 KiB
TypeScript

import '../icon/icon';
import { customElement, property, query, state } from 'lit/decorators.js';
import { html } from 'lit';
import { watch } from '../../internal/watch';
import ShoelaceElement from '../../internal/shoelace-element';
import styles from './animated-image.styles';
import type { CSSResultGroup } from 'lit';
/**
* @summary A component for displaying animated GIFs and WEBPs that play and pause on interaction.
* @documentation https://shoelace.style/components/animated-image
* @status stable
* @since 2.0
*
* @dependency sl-icon
*
* @event sl-load - Emitted when the image loads successfully.
* @event sl-error - Emitted when the image fails to load.
*
* @slot play-icon - Optional play icon to use instead of the default. Works best with `<sl-icon>`.
* @slot pause-icon - Optional pause icon to use instead of the default. Works best with `<sl-icon>`.
*
* @part - control-box - The container that surrounds the pause/play icons and provides their background.
*
* @cssproperty --control-box-size - The size of the icon box.
* @cssproperty --icon-size - The size of the play/pause icons.
*/
@customElement('sl-animated-image')
export default class SlAnimatedImage extends ShoelaceElement {
static styles: CSSResultGroup = styles;
@query('.animated-image__animated') animatedImage: HTMLImageElement;
@state() frozenFrame: string;
@state() isLoaded = false;
/** The path to the image to load. */
@property() src: string;
/** A description of the image used by assistive devices. */
@property() alt: string;
/** Plays the animation. When this attribute is remove, the animation will pause. */
@property({ type: Boolean, reflect: true }) play: boolean;
private handleClick() {
this.play = !this.play;
}
private handleLoad() {
const canvas = document.createElement('canvas');
const { width, height } = this.animatedImage;
canvas.width = width;
canvas.height = height;
canvas.getContext('2d')!.drawImage(this.animatedImage, 0, 0, width, height);
this.frozenFrame = canvas.toDataURL('image/gif');
if (!this.isLoaded) {
this.emit('sl-load');
this.isLoaded = true;
}
}
private handleError() {
this.emit('sl-error');
}
@watch('play', { waitUntilFirstUpdate: true })
handlePlayChange() {
// When the animation starts playing, reset the src so it plays from the beginning. Since the src is cached, this
// won't trigger another request.
if (this.play) {
this.animatedImage.src = '';
this.animatedImage.src = this.src;
}
}
@watch('src')
handleSrcChange() {
this.isLoaded = false;
}
render() {
return html`
<div class="animated-image">
<img
class="animated-image__animated"
src=${this.src}
alt=${this.alt}
crossorigin="anonymous"
aria-hidden=${this.play ? 'false' : 'true'}
@click=${this.handleClick}
@load=${this.handleLoad}
@error=${this.handleError}
/>
${this.isLoaded
? html`
<img
class="animated-image__frozen"
src=${this.frozenFrame}
alt=${this.alt}
aria-hidden=${this.play ? 'true' : 'false'}
@click=${this.handleClick}
/>
<div part="control-box" class="animated-image__control-box">
<slot name="play-icon"><sl-icon name="play-fill" library="system"></sl-icon></slot>
<slot name="pause-icon"><sl-icon name="pause-fill" library="system"></sl-icon></slot>
</div>
`
: ''}
</div>
`;
}
}
declare global {
interface HTMLElementTagNameMap {
'sl-animated-image': SlAnimatedImage;
}
}