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/*
* Copyright (C) 2021 Yomichan Authors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/* global
* MediaUtil
*/
/**
* Class used for loading and validating media during the dictionary import process.
*/
class DictionaryImporterMediaLoader {
/**
* Attempts to load an image using a base64 encoded content and a media type
* and returns its resolution.
* @param mediaType The media type for the image content.
* @param content The binary content for the image, encoded in base64.
* @returns A Promise which resolves with {width, height} on success,
* otherwise an error is thrown.
*/
getImageResolution(mediaType, content) {
return new Promise((resolve, reject) => {
const image = new Image();
const eventListeners = new EventListenerCollection();
const cleanup = () => {
image.removeAttribute('src');
URL.revokeObjectURL(url);
eventListeners.removeAllEventListeners();
};
eventListeners.addEventListener(image, 'load', () => {
const {naturalWidth: width, naturalHeight: height} = image;
cleanup();
resolve({width, height});
}, false);
eventListeners.addEventListener(image, 'error', () => {
cleanup();
reject(new Error('Image failed to load'));
}, false);
const blob = MediaUtil.createBlobFromBase64Content(content, mediaType);
const url = URL.createObjectURL(blob);
image.src = url;
});
}
}
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