lewds.api/src/functions/createCaptcha.js

An api wrapper for lewds.ga for Discord JavaScript Bots

const { Canvas } = require("canvas");
const { shuffle } = require("lodash");
const chars = [
    "a",
    "b",
    "c",
    "d",
    "e",
    "f",
    "g",
    "h",
    "i",
    "j",
    "k",
    "l",
    "m",
    "n",
    "o",
    "p",
    "q",
    "r",
    "s",
    "t",
    "u",
    "v",
    "w",
    "x",
    "y",
    "z",
    "A",
    "B",
    "C",
    "D",
    "E",
    "F",
    "G",
    "H",
    "I",
    "J",
    "K",
    "L",
    "M",
    "N",
    "O",
    "P",
    "Q",
    "R",
    "S",
    "T",
    "U",
    "V",
    "W",
    "X",
    "Y",
    "Z",
    "0",
    "1",
    "2",
    "3",
    "4",
    "5",
    "6",
    "7",
    "8",
    "9"
]

module.exports = async function createCaptcha(caseSensitive) {

    const canvas = new Canvas(400, 250);
    const ctx = canvas.getContext("2d");

    // Set background color
    ctx.globalAlpha = 1;
    ctx.fillStyle = "white";
    ctx.beginPath();
    ctx.fillRect(0, 0, 400, 250);
    ctx.save();

    // Set style for lines
    ctx.strokeStyle = "#000";
    ctx.lineWidth = 4;

    // Draw lines
    ctx.beginPath();

    const coords = [];

    for (let i = 0; i < 4; i++) {
        if (!coords[i])
            coords[i] = [];
        for (let j = 0; j < 5; j++)
            coords[i][j] = Math.round(Math.random() * 80) + j * 80;
        if (!(i % 2))
            coords[i] = shuffle(coords[i]);
    }

    for (let i = 0; i < coords.length; i++) {
        if (!(i % 2)) {
            for (let j = 0; j < coords[i].length; j++) {
                if (!i) {
                    ctx.moveTo(coords[i][j], 0);
                    ctx.lineTo(coords[i + 1][j], 400);
                }
                else {
                    ctx.moveTo(0, coords[i][j]);
                    ctx.lineTo(400, coords[i + 1][j]);
                }
            }
        }
    }

    ctx.stroke();

    // Set style for circles
    ctx.fillStyle = "#000";
    ctx.lineWidth = 0;

    // Draw circles
    for (let i = 0; i < 200; i++) {
        ctx.beginPath();
        ctx.arc(Math.round(Math.random() * 360) + 20, Math.round(Math.random() * 360) + 20, Math.round(Math.random() * 7) + 1, 0, Math.PI * 2);
        ctx.fill();
    }

    // Set style for text
    ctx.font = "80px Sans";
    ctx.fillStyle = "#000";

    // Set position for text
    ctx.textAlign = "center";
    ctx.textBaseline = "top";
    ctx.translate(0, 250);
    ctx.translate(Math.round(Math.random() * 100 - 50) + 200, -1 * Math.round(Math.random() * (250 / 4) - 250 / 8) - 250 / 2);
    ctx.rotate(Math.random() - 0.5);

    // Set text value and print it to canvas
    ctx.beginPath();
    let text = shuffle(chars).slice(0, 6).join("");
    if (caseSensitive !== true) text = text.toLowerCase();
    ctx.fillText(text, 0, 0);

    // Draw foreground noise
    ctx.restore();

    for (let i = 0; i < 5000; i++) {

        ctx.beginPath();

        let color = "#";
        while (color.length < 7) {
            color += Math.round(Math.random() * 16).toString(16);
        }

        color += "a0";
        ctx.fillStyle = color;
        ctx.arc(Math.round(Math.random() * 400), Math.round(Math.random() * 250), Math.random() * 2, 0, Math.PI * 2);
        ctx.fill();
    }

    return {
        image: canvas.toBuffer(),
        text: text
    };
}