Source: ImageEditorHistoryEntry.es.js

  1. /**
  2.  * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
  3.  *
  4.  * This library is free software; you can redistribute it and/or modify it under
  5.  * the terms of the GNU Lesser General Public License as published by the Free
  6.  * Software Foundation; either version 2.1 of the License, or (at your option)
  7.  * any later version.
  8.  *
  9.  * This library is distributed in the hope that it will be useful, but WITHOUT
  10.  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  11.  * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  12.  * details.
  13.  */
  15. /**
  16.  * Image Editor History Entry
  17.  *
  18.  * This class models a step in the image edition process. It stores the
  19.  * Image data at a given point in time so it can be later recovered for
  20.  * undo/redo purposes or other visualization needs.
  21.  * @review
  22.  */
  23. class ImageEditorHistoryEntry {
  25. 	/**
  26. 	 * Constructor
  27. 	 * @review
  28. 	 */
  29. 	constructor(image) {
  30. 		this.dataPromise_ = new Promise((resolve) => {
  32. 			// Preemtively fetch the imageData when all we have is the image url
  34. 			if (image.url && !image.data) {
  35. 				this.loadData_(image.url).then((imageData) =>
  36. 					resolve(imageData)
  37. 				);
  38. 			}
  39. 			else {
  40. 				resolve(image.data);
  41. 			}
  42. 		});
  43. 	}
  45. 	/**
  46. 	 * Fetches an ImageData for a given image url
  47. 	 * @param  {String} imageURL The image url to load
  48. 	 * @protected
  49. 	 * @review
  50. 	 */
  51. 	loadData_(imageURL) {
  52. 		return new Promise((resolve) => {
  53. 			const bufferImage = new Image();
  55. 			bufferImage.onload = () => {
  56. 				const bufferCanvas = document.createElement('canvas');
  57. 				const bufferContext = bufferCanvas.getContext('2d');
  59. 				const height = bufferImage.height;
  60. 				const width = bufferImage.width;
  62. 				bufferCanvas.width = width;
  63. 				bufferCanvas.height = height;
  65. 				bufferContext.drawImage(bufferImage, 0, 0, width, height);
  67. 				resolve(bufferContext.getImageData(0, 0, width, height));
  68. 			};
  70. 			bufferImage.src = imageURL;
  71. 		});
  72. 	}
  74. 	/**
  75. 	 * Fetches the stored ImageData of this history entry
  76. 	 * @return {Promise} A promise that will resolve with the stored ImageData value
  77. 	 * @review
  78. 	 */
  79. 	getImageData() {
  80. 		return this.dataPromise_;
  81. 	}
  82. }
  84. export default ImageEditorHistoryEntry;