Add Crop Image operation

src/core/config/Categories.json

@@ -365,7 +365,8 @@
             "Blur Image",
             "Dither Image",
             "Invert Image",
-            "Flip Image"
+            "Flip Image",
+            "Crop Image"
         ]
     },
     {

src/core/operations/CropImage.mjs

@@ -0,0 +1,139 @@
+/**
+ * @author j433866 [j433866@gmail.com]
+ * @copyright Crown Copyright 2019
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import OperationError from "../errors/OperationError";
+import Magic from "../lib/Magic";
+import { toBase64 } from "../lib/Base64.mjs";
+import jimp from "jimp";
+
+/**
+ * Crop Image operation
+ */
+class CropImage extends Operation {
+
+    /**
+     * CropImage constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Crop Image";
+        this.module = "Image";
+        this.description = "Crops an image to the specified region, or automatically crop edges.<br><br><b><u>Autocrop</u></b><br>Automatically crops same-colour borders from the image.<br><br><u>Autocrop tolerance</u><br>A percentage value for the tolerance of colour difference between pixels.<br><br><u>Only autocrop frames</u><br>Only crop real frames (all sides must have the same border)<br><br><u>Symmetric autocrop</u><br>Force autocrop to be symmetric (top/bottom and left/right are cropped by the same amount)<br><br><u>Autocrop keep border</u><br>The number of pixels of border to leave around the image.";
+        this.infoURL = "https://wikipedia.org/wiki/Cropping_(image)";
+        this.inputType = "byteArray";
+        this.outputType = "byteArray";
+        this.presentType = "html";
+        this.args = [
+            {
+                name: "X Position",
+                type: "number",
+                value: 0,
+                min: 0
+            },
+            {
+                name: "Y Position",
+                type: "number",
+                value: 0,
+                min: 0
+            },
+            {
+                name: "Width",
+                type: "number",
+                value: 10,
+                min: 1
+            },
+            {
+                name: "Height",
+                type: "number",
+                value: 10,
+                min: 1
+            },
+            {
+                name: "Autocrop",
+                type: "boolean",
+                value: false
+            },
+            {
+                name: "Autocrop tolerance (%)",
+                type: "number",
+                value: 0.02,
+                min: 0,
+                max: 100,
+                step: 0.01
+            },
+            {
+                name: "Only autocrop frames",
+                type: "boolean",
+                value: true
+            },
+            {
+                name: "Symmetric autocrop",
+                type: "boolean",
+                value: false
+            },
+            {
+                name: "Autocrop keep border (px)",
+                type: "number",
+                value: 0,
+                min: 0
+            }
+        ];
+    }
+
+    /**
+     * @param {byteArray} input
+     * @param {Object[]} args
+     * @returns {byteArray}
+     */
+    async run(input, args) {
+        // const [firstArg, secondArg] = args;
+        const [xPos, yPos, width, height, autocrop, autoTolerance, autoFrames, autoSymmetric, autoBorder] = args;
+        const type = Magic.magicFileType(input);
+        if (!type || type.mime.indexOf("image") !== 0){
+            throw new OperationError("Invalid file type.");
+        }
+
+        const image = await jimp.read(Buffer.from(input));
+        if (autocrop) {
+            image.autocrop({
+                tolerance: (autoTolerance / 100),
+                cropOnlyFrames: autoFrames,
+                cropSymmetric: autoSymmetric,
+                leaveBorder: autoBorder
+            });
+        } else {
+            image.crop(xPos, yPos, width, height);
+        }
+
+        const imageBuffer = await image.getBufferAsync(jimp.AUTO);
+        return [...imageBuffer];
+    }
+
+    /**
+     * Displays the cropped image using HTML for web apps
+     * @param {byteArray} data
+     * @returns {html}
+     */
+    present(data) {
+        if (!data.length) return "";
+
+        let dataURI = "data:";
+        const type = Magic.magicFileType(data);
+        if (type && type.mime.indexOf("image") === 0){
+            dataURI += type.mime + ";";
+        } else {
+            throw new OperationError("Invalid file type");
+        }
+        dataURI += "base64," + toBase64(data);
+
+        return "<img src='" + dataURI + "'>";
+    }
+
+}
+
+export default CropImage;