superset SequentialScheme 源码

superset SequentialScheme 代码

文件路径：/superset-frontend/packages/superset-ui-core/src/color/SequentialScheme.ts

/*
 * 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 { scaleLinear } from 'd3-scale';
import {
  interpolateHcl,
  interpolateNumber,
  piecewise,
  quantize,
} from 'd3-interpolate';
import ColorScheme, { ColorSchemeConfig } from './ColorScheme';

export interface SequentialSchemeConfig extends ColorSchemeConfig {
  isDiverging?: boolean;
}

export default class SequentialScheme extends ColorScheme {
  isDiverging: boolean;

  constructor(config: SequentialSchemeConfig) {
    super(config);
    const { isDiverging = false } = config;
    this.isDiverging = isDiverging;
  }

  /**
   * Return a linear scale with a new domain interpolated from the input domain
   * to match the number of elements in the color scheme
   * because D3 continuous scale uses piecewise mapping between domain and range.
   * This is a common use-case when the domain is [min, max]
   * and the palette has more than two colors.
   *
   * @param domain domain of the scale
   * @param modifyRange Set this to true if you don't want to modify the domain and
   * want to interpolate range to have the same number of elements with domain instead.
   */
  createLinearScale(domain: number[] = [0, 1], modifyRange = false) {
    const scale = scaleLinear<string>().interpolate(interpolateHcl).clamp(true);

    return modifyRange || domain.length === this.colors.length
      ? scale.domain(domain).range(this.getColors(domain.length))
      : scale
          .domain(
            quantize(piecewise(interpolateNumber, domain), this.colors.length),
          )
          .range(this.colors);
  }

  /**
   * Get colors from this scheme
   * @param numColors number of colors to return.
   * Will interpolate the current scheme to match the number of colors requested
   * @param extent The extent of the color range to use.
   * For example [0.2, 1] will rescale the color scheme
   * such that color values in the range [0, 0.2) are excluded from the scheme.
   */
  getColors(
    numColors = this.colors.length,
    extent: number[] = [0, 1],
  ): string[] {
    if (
      numColors === this.colors.length &&
      extent[0] === 0 &&
      extent[1] === 1
    ) {
      return this.colors;
    }

    const piecewiseScale: (t: number) => string = piecewise(
      interpolateHcl,
      this.colors,
    );
    const adjustExtent = scaleLinear().range(extent).clamp(true);

    return quantize<string>(
      t => piecewiseScale(adjustExtent(t) as number),
      numColors,
    );
  }
}

相关信息

superset 源码目录

相关文章

superset CategoricalColorNamespace 源码

superset CategoricalColorScale 源码

superset CategoricalScheme 源码

superset CategoricalSchemeRegistrySingleton 源码

superset ColorScheme 源码

superset ColorSchemeRegistry 源码

superset SequentialSchemeRegistrySingleton 源码

superset SharedLabelColorSingleton 源码

superset index 源码

superset stringifyAndTrim 源码