Rotate command

commands/edit-image/rotate.js

@@ -0,0 +1,67 @@
+const Command = require('../../structures/Command');
+const { createCanvas, loadImage } = require('canvas');
+const request = require('node-superfetch');
+const { centerImage } = require('../../util/Canvas');
+
+module.exports = class RotateCommand extends Command {
+	constructor(client) {
+		super(client, {
+			name: 'rotate',
+			group: 'edit-image',
+			memberName: 'rotate',
+			description: 'Draws an image or a user\'s avatar but rotated a number of degrees.',
+			throttling: {
+				usages: 1,
+				duration: 10
+			},
+			clientPermissions: ['ATTACH_FILES'],
+			args: [
+				{
+					key: 'degrees',
+					prompt: 'How many degrees do you want to rotate the image?',
+					type: 'integer',
+					min: -360,
+					max: 360
+				},
+				{
+					key: 'image',
+					prompt: 'What image would you like to edit?',
+					type: 'image-or-avatar',
+					default: msg => msg.author.displayAvatarURL({ format: 'png', size: 512 })
+				}
+			]
+		});
+	}
+
+	async run(msg, { degrees, image }) {
+		try {
+			const { body } = await request.get(image);
+			const data = await loadImage(body);
+			const newDims = this.adjustCanvasSize(data.width, data.height, degrees);
+			const canvas = createCanvas(newDims.width, newDims.height);
+			const ctx = canvas.getContext('2d');
+			ctx.translate(canvas.width / 2, canvas.height / 2);
+			ctx.rotate(degrees * (Math.PI / 180));
+			ctx.translate(-(canvas.width / 2), -(canvas.height / 2));
+			const { x, y, width, height } = centerImage(canvas, data);
+			ctx.drawImage(data, x, y, width, height);
+			ctx.translate(canvas.width / 2, canvas.height / 2);
+			ctx.rotate(-degrees * (Math.PI / 180));
+			const attachment = canvas.toBuffer();
+			if (Buffer.byteLength(attachment) > 8e+6) return msg.reply('Resulting image was above 8 MB.');
+			return msg.say({ files: [{ attachment, name: 'rotate.png' }] });
+		} catch (err) {
+			return msg.reply(`Oh no, an error occurred: \`${err.message}\`. Try again later!`);
+		}
+	}
+
+	adjustCanvasSize(width, height, angle) {
+		let cos = Math.cos(angle * (Math.PI / 180));
+		let sin = Math.sin(angle * (Math.PI / 180));
+		if (sin < 0) sin = -sin;
+		if (cos < 0) cos = -cos;
+		const newWidth = (height * sin) + (width * cos);
+		const newHeight = (height * cos) + (width * sin);
+		return { width: newWidth, height: newHeight };
+	}
+};