CyberChef/src/core/operations/DitherImage.mjs

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/**
* @author j433866 [j433866@gmail.com]
* @copyright Crown Copyright 2019
* @license Apache-2.0
*/
import Operation from "../Operation.mjs";
import OperationError from "../errors/OperationError.mjs";
import { isImage } from "../lib/FileType.mjs";
import { toBase64 } from "../lib/Base64.mjs";
import { isWorkerEnvironment } from "../Utils.mjs";
import jimp from "jimp";
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/**
* Image Dither operation
*/
class DitherImage extends Operation {
/**
* DitherImage constructor
*/
constructor() {
super();
this.name = "Dither Image";
this.module = "Image";
this.description = "Apply a dither effect to an image.";
this.infoURL = "https://wikipedia.org/wiki/Dither";
this.inputType = "ArrayBuffer";
this.outputType = "ArrayBuffer";
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this.presentType = "html";
this.args = [];
}
/**
* @param {ArrayBuffer} input
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* @param {Object[]} args
* @returns {byteArray}
*/
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async run(input, args) {
if (!isImage(input)) {
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throw new OperationError("Invalid file type.");
}
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let image;
try {
image = await jimp.read(input);
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} catch (err) {
throw new OperationError(`Error loading image. (${err})`);
}
try {
if (isWorkerEnvironment())
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self.sendStatusMessage("Applying dither to image...");
image.dither565();
let imageBuffer;
if (image.getMIME() === "image/gif") {
imageBuffer = await image.getBufferAsync(jimp.MIME_PNG);
} else {
imageBuffer = await image.getBufferAsync(jimp.AUTO);
}
return imageBuffer.buffer;
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} catch (err) {
throw new OperationError(`Error applying dither to image. (${err})`);
}
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}
/**
* Displays the dithered image using HTML for web apps
* @param {ArrayBuffer} data
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* @returns {html}
*/
present(data) {
if (!data.byteLength) return "";
const dataArray = new Uint8Array(data);
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const type = isImage(dataArray);
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if (!type) {
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throw new OperationError("Invalid file type.");
}
return `<img src="data:${type};base64,${toBase64(dataArray)}">`;
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}
}
export default DitherImage;