en/builder/src/echarts/scale/Interval.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.
*/

/**
 * Interval scale
 * @module echarts/scale/Interval
 */
import * as numberUtil from '../util/number';
import * as formatUtil from '../util/format';
import Scale from './Scale';
import * as helper from './helper';
var roundNumber = numberUtil.round;
/**
 * @alias module:echarts/coord/scale/Interval
 * @constructor
 */

var IntervalScale = Scale.extend({
  type: 'interval',
  _interval: 0,
  _intervalPrecision: 2,
  setExtent: function (start, end) {
    var thisExtent = this._extent; //start,end may be a Number like '25',so...

    if (!isNaN(start)) {
      thisExtent[0] = parseFloat(start);
    }

    if (!isNaN(end)) {
      thisExtent[1] = parseFloat(end);
    }
  },
  unionExtent: function (other) {
    var extent = this._extent;
    other[0] < extent[0] && (extent[0] = other[0]);
    other[1] > extent[1] && (extent[1] = other[1]); // unionExtent may called by it's sub classes

    IntervalScale.prototype.setExtent.call(this, extent[0], extent[1]);
  },

  /**
   * Get interval
   */
  getInterval: function () {
    return this._interval;
  },

  /**
   * Set interval
   */
  setInterval: function (interval) {
    this._interval = interval; // Dropped auto calculated niceExtent and use user setted extent
    // We assume user wan't to set both interval, min, max to get a better result

    this._niceExtent = this._extent.slice();
    this._intervalPrecision = helper.getIntervalPrecision(interval);
  },

  /**
   * @param {boolean} [expandToNicedExtent=false] If expand the ticks to niced extent.
   * @return {Array.<number>}
   */
  getTicks: function (expandToNicedExtent) {
    var interval = this._interval;
    var extent = this._extent;
    var niceTickExtent = this._niceExtent;
    var intervalPrecision = this._intervalPrecision;
    var ticks = []; // If interval is 0, return [];

    if (!interval) {
      return ticks;
    } // Consider this case: using dataZoom toolbox, zoom and zoom.


    var safeLimit = 10000;

    if (extent[0] < niceTickExtent[0]) {
      if (expandToNicedExtent) {
        ticks.push(roundNumber(niceTickExtent[0] - interval, intervalPrecision));
      } else {
        ticks.push(extent[0]);
      }
    }

    var tick = niceTickExtent[0];

    while (tick <= niceTickExtent[1]) {
      ticks.push(tick); // Avoid rounding error

      tick = roundNumber(tick + interval, intervalPrecision);

      if (tick === ticks[ticks.length - 1]) {
        // Consider out of safe float point, e.g.,
        // -3711126.9907707 + 2e-10 === -3711126.9907707
        break;
      }

      if (ticks.length > safeLimit) {
        return [];
      }
    } // Consider this case: the last item of ticks is smaller
    // than niceTickExtent[1] and niceTickExtent[1] === extent[1].


    var lastNiceTick = ticks.length ? ticks[ticks.length - 1] : niceTickExtent[1];

    if (extent[1] > lastNiceTick) {
      if (expandToNicedExtent) {
        ticks.push(roundNumber(lastNiceTick + interval, intervalPrecision));
      } else {
        ticks.push(extent[1]);
      }
    }

    return ticks;
  },

  /**
   * @param {number} [splitNumber=5]
   * @return {Array.<Array.<number>>}
   */
  getMinorTicks: function (splitNumber) {
    var ticks = this.getTicks(true);
    var minorTicks = [];
    var extent = this.getExtent();

    for (var i = 1; i < ticks.length; i++) {
      var nextTick = ticks[i];
      var prevTick = ticks[i - 1];
      var count = 0;
      var minorTicksGroup = [];
      var interval = nextTick - prevTick;
      var minorInterval = interval / splitNumber;

      while (count < splitNumber - 1) {
        var minorTick = numberUtil.round(prevTick + (count + 1) * minorInterval); // For the first and last interval. The count may be less than splitNumber.

        if (minorTick > extent[0] && minorTick < extent[1]) {
          minorTicksGroup.push(minorTick);
        }

        count++;
      }

      minorTicks.push(minorTicksGroup);
    }

    return minorTicks;
  },

  /**
   * @param {number} data
   * @param {Object} [opt]
   * @param {number|string} [opt.precision] If 'auto', use nice presision.
   * @param {boolean} [opt.pad] returns 1.50 but not 1.5 if precision is 2.
   * @return {string}
   */
  getLabel: function (data, opt) {
    if (data == null) {
      return '';
    }

    var precision = opt && opt.precision;

    if (precision == null) {
      precision = numberUtil.getPrecisionSafe(data) || 0;
    } else if (precision === 'auto') {
      // Should be more precise then tick.
      precision = this._intervalPrecision;
    } // (1) If `precision` is set, 12.005 should be display as '12.00500'.
    // (2) Use roundNumber (toFixed) to avoid scientific notation like '3.5e-7'.


    data = roundNumber(data, precision, true);
    return formatUtil.addCommas(data);
  },

  /**
   * Update interval and extent of intervals for nice ticks
   *
   * @param {number} [splitNumber = 5] Desired number of ticks
   * @param {number} [minInterval]
   * @param {number} [maxInterval]
   */
  niceTicks: function (splitNumber, minInterval, maxInterval) {
    splitNumber = splitNumber || 5;
    var extent = this._extent;
    var span = extent[1] - extent[0];

    if (!isFinite(span)) {
      return;
    } // User may set axis min 0 and data are all negative
    // FIXME If it needs to reverse ?


    if (span < 0) {
      span = -span;
      extent.reverse();
    }

    var result = helper.intervalScaleNiceTicks(extent, splitNumber, minInterval, maxInterval);
    this._intervalPrecision = result.intervalPrecision;
    this._interval = result.interval;
    this._niceExtent = result.niceTickExtent;
  },

  /**
   * Nice extent.
   * @param {Object} opt
   * @param {number} [opt.splitNumber = 5] Given approx tick number
   * @param {boolean} [opt.fixMin=false]
   * @param {boolean} [opt.fixMax=false]
   * @param {boolean} [opt.minInterval]
   * @param {boolean} [opt.maxInterval]
   */
  niceExtent: function (opt) {
    var extent = this._extent; // If extent start and end are same, expand them

    if (extent[0] === extent[1]) {
      if (extent[0] !== 0) {
        // Expand extent
        var expandSize = extent[0]; // In the fowllowing case
        //      Axis has been fixed max 100
        //      Plus data are all 100 and axis extent are [100, 100].
        // Extend to the both side will cause expanded max is larger than fixed max.
        // So only expand to the smaller side.

        if (!opt.fixMax) {
          extent[1] += expandSize / 2;
          extent[0] -= expandSize / 2;
        } else {
          extent[0] -= expandSize / 2;
        }
      } else {
        extent[1] = 1;
      }
    }

    var span = extent[1] - extent[0]; // If there are no data and extent are [Infinity, -Infinity]

    if (!isFinite(span)) {
      extent[0] = 0;
      extent[1] = 1;
    }

    this.niceTicks(opt.splitNumber, opt.minInterval, opt.maxInterval); // var extent = this._extent;

    var interval = this._interval;

    if (!opt.fixMin) {
      extent[0] = roundNumber(Math.floor(extent[0] / interval) * interval);
    }

    if (!opt.fixMax) {
      extent[1] = roundNumber(Math.ceil(extent[1] / interval) * interval);
    }
  }
});
/**
 * @return {module:echarts/scale/Time}
 */

IntervalScale.create = function () {
  return new IntervalScale();
};

export default IntervalScale;