@adobe/leonardo-contrast-colors/backgroundcolor.js

/*
Copyright 2019 Adobe. All rights reserved.
This file is licensed to you under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License. You may obtain a copy
of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under
the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
OF ANY KIND, either express or implied. See the License for the specific language
governing permissions and limitations under the License.
*/

const {
  cArray,
  convertColorValue,
  createScale,
  removeDuplicates,
} = require('./utils');

const { Color } = require('./color');

class BackgroundColor extends Color {
  get backgroundColorScale() {
    if (!this._backgroundColorScale) {
      this._generateColorScale();
    }
    return this._backgroundColorScale;
  }

  _generateColorScale() {
    // This would create a 100 color value array based on all parameters,
    // which can be used for sliding lightness as a background color

    // Call original generateColorScale method in the context of our background color
    // Then we can run the code for Color, but we've added in more below.
    Color.prototype._generateColorScale.call(this);

    // create massive scale
    const backgroundColorScale = createScale({ swatches: 1000, colorKeys: this._colorKeys, colorspace: this._colorspace, shift: 1, smooth: this._smooth });

    // Inject original keycolors to ensure they are present in the background options
    backgroundColorScale.push(...this.colorKeys);

    const colorObj = backgroundColorScale
      // Convert to HSLuv and keep track of original indices
      .map((c, i) => ({ value: Math.round(cArray(c)[2]), index: i }));

    const bgColorArrayFiltered = removeDuplicates(colorObj, 'value')
      .map((data) => backgroundColorScale[data.index]);

    // Manually cap the background array at 100 colors, then add white back to the end
    // since it sometimes gets removed.
    bgColorArrayFiltered.length = 100;
    bgColorArrayFiltered.push('#ffffff');

    this._backgroundColorScale = bgColorArrayFiltered.map((color) => convertColorValue(color, this._output));

    return this._backgroundColorScale;
  }
}
module.exports = { BackgroundColor };