Add upstream

wp-content/plugins/jetpack/modules/photon/photon.js

@@ -0,0 +1,59 @@
+/* jshint onevar: false */
+
+( function() {
+	function recalculate() {
+		if ( this.complete ) {
+			// Support for lazy loading: if there is a lazy-src attribute and it's value
+			// is not the same as the current src we should wait until the image load event
+			var lazySrc = this.getAttribute( 'data-lazy-src' );
+			if ( lazySrc && this.src !== lazySrc ) {
+				this.addEventListener( 'onload', recalculate );
+				return;
+			}
+
+			// Copying CSS width/height into element attributes.
+			var width = this.width;
+			var height = this.height;
+			if ( width && width > 0 && height && height > 0 ) {
+				this.setAttribute( 'width', width );
+				this.setAttribute( 'height', height );
+
+				reset_for_retina( this );
+			}
+		} else {
+			this.addEventListener( 'onload', recalculate );
+			return;
+		}
+	}
+
+	/**
+	 * For images lacking explicit dimensions and needing them, try to add them.
+	 */
+	var restore_dims = function() {
+			var elements = document.querySelectorAll( 'img[data-recalc-dims]' );
+			for ( var i = 0; i < elements.length; i++ ) {
+				recalculate.call( elements[ i ] );
+			}
+		},
+		/**
+		 * Modify given image's markup so that devicepx-jetpack.js will act on the image and it won't be reprocessed by this script.
+		 */
+		reset_for_retina = function( img ) {
+			img.removeAttribute( 'data-recalc-dims' );
+			img.removeAttribute( 'scale' );
+		};
+
+	/**
+	 * Check both when page loads, and when IS is triggered.
+	 */
+	if ( typeof window !== 'undefined' && typeof document !== 'undefined' ) {
+		// `DOMContentLoaded` may fire before the script has a chance to run
+		if ( document.readyState === 'loading' ) {
+			document.addEventListener( 'DOMContentLoaded', restore_dims );
+		} else {
+			restore_dims();
+		}
+	}
+
+	document.body.addEventListener( 'post-load', restore_dims );
+} )();