Ordinal.js 3.45 KB
/*
* 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.
*/

/**
 * Linear continuous scale
 * @module echarts/coord/scale/Ordinal
 *
 * http://en.wikipedia.org/wiki/Level_of_measurement
 */

// FIXME only one data

import * as zrUtil from 'zrender/src/core/util';
import Scale from './Scale';
import OrdinalMeta from '../data/OrdinalMeta';

var scaleProto = Scale.prototype;

var OrdinalScale = Scale.extend({

    type: 'ordinal',

    /**
     * @param {module:echarts/data/OrdianlMeta|Array.<string>} ordinalMeta
     */
    init: function (ordinalMeta, extent) {
        // Caution: Should not use instanceof, consider ec-extensions using
        // import approach to get OrdinalMeta class.
        if (!ordinalMeta || zrUtil.isArray(ordinalMeta)) {
            ordinalMeta = new OrdinalMeta({categories: ordinalMeta});
        }
        this._ordinalMeta = ordinalMeta;
        this._extent = extent || [0, ordinalMeta.categories.length - 1];
    },

    parse: function (val) {
        return typeof val === 'string'
            ? this._ordinalMeta.getOrdinal(val)
            // val might be float.
            : Math.round(val);
    },

    contain: function (rank) {
        rank = this.parse(rank);
        return scaleProto.contain.call(this, rank)
            && this._ordinalMeta.categories[rank] != null;
    },

    /**
     * Normalize given rank or name to linear [0, 1]
     * @param {number|string} [val]
     * @return {number}
     */
    normalize: function (val) {
        return scaleProto.normalize.call(this, this.parse(val));
    },

    scale: function (val) {
        return Math.round(scaleProto.scale.call(this, val));
    },

    /**
     * @return {Array}
     */
    getTicks: function () {
        var ticks = [];
        var extent = this._extent;
        var rank = extent[0];

        while (rank <= extent[1]) {
            ticks.push(rank);
            rank++;
        }

        return ticks;
    },

    /**
     * Get item on rank n
     * @param {number} n
     * @return {string}
     */
    getLabel: function (n) {
        if (!this.isBlank()) {
            // Note that if no data, ordinalMeta.categories is an empty array.
            return this._ordinalMeta.categories[n];
        }
    },

    /**
     * @return {number}
     */
    count: function () {
        return this._extent[1] - this._extent[0] + 1;
    },

    /**
     * @override
     */
    unionExtentFromData: function (data, dim) {
        this.unionExtent(data.getApproximateExtent(dim));
    },

    getOrdinalMeta: function () {
        return this._ordinalMeta;
    },

    niceTicks: zrUtil.noop,
    niceExtent: zrUtil.noop
});

/**
 * @return {module:echarts/scale/Time}
 */
OrdinalScale.create = function () {
    return new OrdinalScale();
};

export default OrdinalScale;