Merge remote-tracking branch 'phet-core-history-copy/main'

js/MipmapElement.ts

@@ -0,0 +1,41 @@
+// Copyright 2022-2024, University of Colorado Boulder
+
+import asyncLoader from './asyncLoader.js';
+import phetCore from './phetCore.js';
+
+/**
+ * Size and raster data for levels in a mipmap.  See also type Mipmap in Imageable.ts.  Defined in phet-core instead of
+ * scenery because it is loaded upstream and should not have any downstream dependencies such as scenery.
+ *
+ * @author Sam Reid (PhET Interactive Simulations)
+ */
+export default class MipmapElement {
+  public readonly width: number;
+  public readonly height: number;
+  public readonly url: string;
+  public readonly img: HTMLImageElement;
+  public readonly canvas: HTMLCanvasElement;
+
+  public constructor( width: number, height: number, url: string, lock = true ) {
+
+    this.width = width;
+    this.height = height;
+    this.url = url;
+
+    this.img = new Image(); // eslint-disable-line phet/no-html-constructors
+    this.img.src = this.url; // trigger the loading of the image for its level
+
+    this.canvas = document.createElement( 'canvas' );
+    this.canvas.width = this.width;
+    this.canvas.height = this.height;
+
+    const context = this.canvas.getContext( '2d' )!;
+    const unlock = lock ? asyncLoader.createLock( this.img ) : null;
+    this.img.onload = () => {
+      context.drawImage( this.img, 0, 0 );
+      unlock && unlock();
+    };
+  }
+}
+
+phetCore.register( 'MipmapElement', MipmapElement );