index.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports["default"] = void 0;

var _utils = require("@jimp/utils");

/**
 * Applies a minimum color threshold to a greyscale image.  Converts image to greyscale by default
 * @param {number} options object
 *  max: A number auto limited between 0 - 255
 *  replace: (optional) A number auto limited between 0 - 255 (default 255)
 *  autoGreyscale: (optional) A boolean whether to apply greyscale beforehand (default true)
 * @param {number} cb (optional) a callback for when complete
 * @return {this} this for chaining of methods
 */
var _default = function _default() {
  return {
    threshold: function threshold(_ref, cb) {
      var _this = this;

      var max = _ref.max,
          _ref$replace = _ref.replace,
          replace = _ref$replace === void 0 ? 255 : _ref$replace,
          _ref$autoGreyscale = _ref.autoGreyscale,
          autoGreyscale = _ref$autoGreyscale === void 0 ? true : _ref$autoGreyscale;

      if (typeof max !== 'number') {
        return _utils.throwError.call(this, 'max must be a number', cb);
      }

      if (typeof replace !== 'number') {
        return _utils.throwError.call(this, 'replace must be a number', cb);
      }

      if (typeof autoGreyscale !== 'boolean') {
        return _utils.throwError.call(this, 'autoGreyscale must be a boolean', cb);
      }

      max = this.constructor.limit255(max);
      replace = this.constructor.limit255(replace);

      if (autoGreyscale) {
        this.greyscale();
      }

      this.scanQuiet(0, 0, this.bitmap.width, this.bitmap.height, function (x, y, idx) {
        var grey = _this.bitmap.data[idx] < max ? _this.bitmap.data[idx] : replace;
        _this.bitmap.data[idx] = grey;
        _this.bitmap.data[idx + 1] = grey;
        _this.bitmap.data[idx + 2] = grey;
      });

      if ((0, _utils.isNodePattern)(cb)) {
        cb.call(this, null, this);
      }

      return this;
    }
  };
};

exports["default"] = _default;
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