Accueil / npm / three@0.186.1 / src / loaders / ImageLoader.js
ImageLoader.js
import { Cache } from './Cache.js';
import { Loader } from './Loader.js';
import { createElementNS } from '../utils.js';
const _loading = new WeakMap();
/**
* A loader for loading images. The class loads images with the HTML `Image` API.
*
* ```js
* const loader = new THREE.ImageLoader();
* const image = await loader.loadAsync( 'image.png' );
* ```
* Please note that `ImageLoader` has dropped support for progress
* events in `r84`. For an `ImageLoader` that supports progress events, see
* [this thread](https://github.com/mrdoob/three.js/issues/10439#issuecomment-275785639).
*
* @augments Loader
*/
class ImageLoader extends Loader {
/**
* Constructs a new image loader.
*
* @param {LoadingManager} [manager] - The loading manager.
*/
constructor( manager ) {
super( manager );
}
/**
* Starts loading from the given URL and passes the loaded image
* to the `onLoad()` callback. The method also returns a new `Image` object which can
* directly be used for texture creation. If you do it this way, the texture
* may pop up in your scene once the respective loading process is finished.
*
* @param {string} url - The path/URL of the file to be loaded. This can also be a data URI.
* @param {function(Image)} onLoad - Executed when the loading process has been finished.
* @param {onProgressCallback} onProgress - Unsupported in this loader.
* @param {onErrorCallback} onError - Executed when errors occur.
* @return {Image} The image.
*/
load( url, onLoad, onProgress, onError ) {
if ( this.path !== undefined ) url = this.path + url;
url = this.manager.resolveURL( url );
const scope = this;
const cached = Cache.get( `image:${url}` );
if ( cached !== undefined ) {
if ( cached.complete === true ) {
scope.manager.itemStart( url );
setTimeout( function () {
if ( onLoad ) onLoad( cached );
scope.manager.itemEnd( url );
}, 0 );
} else {
let arr = _loading.get( cached );
if ( arr === undefined ) {
arr = [];
_loading.set( cached, arr );
}
arr.push( { onLoad, onError } );
}
return cached;
}
const image = createElementNS( 'img' );
function onImageLoad() {
removeEventListeners();
if ( onLoad ) onLoad( this );
//
const callbacks = _loading.get( this ) || [];
for ( let i = 0; i < callbacks.length; i ++ ) {
const callback = callbacks[ i ];
if ( callback.onLoad ) callback.onLoad( this );
}
_loading.delete( this );
scope.manager.itemEnd( url );
}
function onImageError( event ) {
removeEventListeners();
if ( onError ) onError( event );
Cache.remove( `image:${url}` );
//
const callbacks = _loading.get( this ) || [];
for ( let i = 0; i < callbacks.length; i ++ ) {
const callback = callbacks[ i ];
if ( callback.onError ) callback.onError( event );
}
_loading.delete( this );
scope.manager.itemError( url );
scope.manager.itemEnd( url );
}
function removeEventListeners() {
image.removeEventListener( 'load', onImageLoad, false );
image.removeEventListener( 'error', onImageError, false );
}
image.addEventListener( 'load', onImageLoad, false );
image.addEventListener( 'error', onImageError, false );
if ( url.slice( 0, 5 ) !== 'data:' ) {
if ( this.crossOrigin !== undefined ) image.crossOrigin = this.crossOrigin;
}
Cache.add( `image:${url}`, image );
scope.manager.itemStart( url );
image.src = url;
return image;
}
}
export { ImageLoader };