zh/builder/src/echarts/model/mixin/colorPalette.js

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* 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 CONDITIONS OF ANY
* KIND, either express or implied.  See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import { makeInner, normalizeToArray } from '../../util/model';
var inner = makeInner();

function getNearestColorPalette(colors, requestColorNum) {
  var paletteNum = colors.length; // TODO colors must be in order

  for (var i = 0; i < paletteNum; i++) {
    if (colors[i].length > requestColorNum) {
      return colors[i];
    }
  }

  return colors[paletteNum - 1];
}

export default {
  clearColorPalette: function () {
    inner(this).colorIdx = 0;
    inner(this).colorNameMap = {};
  },

  /**
   * @param {string} name MUST NOT be null/undefined. Otherwise call this function
   *                 twise with the same parameters will get different result.
   * @param {Object} [scope=this]
   * @param {Object} [requestColorNum]
   * @return {string} color string.
   */
  getColorFromPalette: function (name, scope, requestColorNum) {
    scope = scope || this;
    var scopeFields = inner(scope);
    var colorIdx = scopeFields.colorIdx || 0;
    var colorNameMap = scopeFields.colorNameMap = scopeFields.colorNameMap || {}; // Use `hasOwnProperty` to avoid conflict with Object.prototype.

    if (colorNameMap.hasOwnProperty(name)) {
      return colorNameMap[name];
    }

    var defaultColorPalette = normalizeToArray(this.get('color', true));
    var layeredColorPalette = this.get('colorLayer', true);
    var colorPalette = requestColorNum == null || !layeredColorPalette ? defaultColorPalette : getNearestColorPalette(layeredColorPalette, requestColorNum); // In case can't find in layered color palette.

    colorPalette = colorPalette || defaultColorPalette;

    if (!colorPalette || !colorPalette.length) {
      return;
    }

    var color = colorPalette[colorIdx];

    if (name) {
      colorNameMap[name] = color;
    }

    scopeFields.colorIdx = (colorIdx + 1) % colorPalette.length;
    return color;
  }
};