public/zh/builder/src/echarts/scale/helper.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.
*/

/**
 * For testable.
 */
import * as numberUtil from '../util/number';
var roundNumber = numberUtil.round;
/**
 * @param {Array.<number>} extent Both extent[0] and extent[1] should be valid number.
 *                                Should be extent[0] < extent[1].
 * @param {number} splitNumber splitNumber should be >= 1.
 * @param {number} [minInterval]
 * @param {number} [maxInterval]
 * @return {Object} {interval, intervalPrecision, niceTickExtent}
 */

export function intervalScaleNiceTicks(extent, splitNumber, minInterval, maxInterval) {
  var result = {};
  var span = extent[1] - extent[0];
  var interval = result.interval = numberUtil.nice(span / splitNumber, true);

  if (minInterval != null && interval < minInterval) {
    interval = result.interval = minInterval;
  }

  if (maxInterval != null && interval > maxInterval) {
    interval = result.interval = maxInterval;
  } // Tow more digital for tick.


  var precision = result.intervalPrecision = getIntervalPrecision(interval); // Niced extent inside original extent

  var niceTickExtent = result.niceTickExtent = [roundNumber(Math.ceil(extent[0] / interval) * interval, precision), roundNumber(Math.floor(extent[1] / interval) * interval, precision)];
  fixExtent(niceTickExtent, extent);
  return result;
}
/**
 * @param {number} interval
 * @return {number} interval precision
 */

export function getIntervalPrecision(interval) {
  // Tow more digital for tick.
  return numberUtil.getPrecisionSafe(interval) + 2;
}

function clamp(niceTickExtent, idx, extent) {
  niceTickExtent[idx] = Math.max(Math.min(niceTickExtent[idx], extent[1]), extent[0]);
} // In some cases (e.g., splitNumber is 1), niceTickExtent may be out of extent.


export function fixExtent(niceTickExtent, extent) {
  !isFinite(niceTickExtent[0]) && (niceTickExtent[0] = extent[0]);
  !isFinite(niceTickExtent[1]) && (niceTickExtent[1] = extent[1]);
  clamp(niceTickExtent, 0, extent);
  clamp(niceTickExtent, 1, extent);

  if (niceTickExtent[0] > niceTickExtent[1]) {
    niceTickExtent[0] = niceTickExtent[1];
  }
}
export function intervalScaleGetTicks(interval, extent, niceTickExtent, 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]) {
    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].


  if (extent[1] > (ticks.length ? ticks[ticks.length - 1] : niceTickExtent[1])) {
    ticks.push(extent[1]);
  }

  return ticks;
}