53 lines
2.2 KiB
JavaScript
53 lines
2.2 KiB
JavaScript
/*
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* Copyright (C) 2021-2022 Yomichan Authors
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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/**
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* Class used for loading and validating media during the dictionary import process.
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*/
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class DictionaryImporterMediaLoader {
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/**
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* Attempts to load an image using an ArrayBuffer and a media type to return details about it.
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* @param content The binary content for the image, encoded as an ArrayBuffer.
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* @param mediaType The media type for the image content.
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* @returns A Promise which resolves with {content, width, height} on success, otherwise an error is thrown.
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*/
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getImageDetails(content, mediaType, transfer) {
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return new Promise((resolve, reject) => {
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const image = new Image();
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const eventListeners = new EventListenerCollection();
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const cleanup = () => {
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image.removeAttribute('src');
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URL.revokeObjectURL(url);
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eventListeners.removeAllEventListeners();
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};
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eventListeners.addEventListener(image, 'load', () => {
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const {naturalWidth: width, naturalHeight: height} = image;
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if (Array.isArray(transfer)) { transfer.push(content); }
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cleanup();
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resolve({content, width, height});
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}, false);
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eventListeners.addEventListener(image, 'error', () => {
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cleanup();
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reject(new Error('Image failed to load'));
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}, false);
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const blob = new Blob([content], {type: mediaType});
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const url = URL.createObjectURL(blob);
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image.src = url;
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});
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}
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}
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