server/node_modules/@jimp/plugin-circle/src/index.js

import { isNodePattern } from "@jimp/utils";

/**
 * Creates a circle out of an image.
 * @param {function(Error, Jimp)} options (optional) radius, x, y
 * @param {function(Error, Jimp)} cb (optional) a callback for when complete
 * @returns {Jimp} this for chaining of methods
 */
export default () => ({
  circle(options = {}, cb) {
    if (typeof options === "function") {
      cb = options;
      options = {};
    }

    const radius =
      options.radius ||
      (this.bitmap.width > this.bitmap.height
        ? this.bitmap.height
        : this.bitmap.width) / 2;

    const center = {
      x: typeof options.x === "number" ? options.x : this.bitmap.width / 2,
      y: typeof options.y === "number" ? options.y : this.bitmap.height / 2,
    };

    this.scanQuiet(
      0,
      0,
      this.bitmap.width,
      this.bitmap.height,
      function (x, y, idx) {
        const curR = Math.sqrt(
          Math.pow(x - center.x, 2) + Math.pow(y - center.y, 2)
        );

        if (radius - curR <= 0.0) {
          this.bitmap.data[idx + 3] = 0;
        } else if (radius - curR < 1.0) {
          this.bitmap.data[idx + 3] = 255 * (radius - curR);
        }
      }
    );

    if (isNodePattern(cb)) {
      cb.call(this, null, this);
    }

    return this;
  },
});