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node_modules/echarts/src/coord/polar/AngleAxis.js 3.92 KB
aaac7fed   liuqimichale   add
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  /*
  * 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 * as zrUtil from 'zrender/src/core/util';
  import * as textContain from 'zrender/src/contain/text';
  import Axis from '../Axis';
  import {makeInner} from '../../util/model';
  
  var inner = makeInner();
  
  function AngleAxis(scale, angleExtent) {
  
      angleExtent = angleExtent || [0, 360];
  
      Axis.call(this, 'angle', scale, angleExtent);
  
      /**
       * Axis type
       *  - 'category'
       *  - 'value'
       *  - 'time'
       *  - 'log'
       * @type {string}
       */
      this.type = 'category';
  }
  
  AngleAxis.prototype = {
  
      constructor: AngleAxis,
  
      /**
       * @override
       */
      pointToData: function (point, clamp) {
          return this.polar.pointToData(point, clamp)[this.dim === 'radius' ? 0 : 1];
      },
  
      dataToAngle: Axis.prototype.dataToCoord,
  
      angleToData: Axis.prototype.coordToData,
  
      /**
       * Only be called in category axis.
       * Angle axis uses text height to decide interval
       *
       * @override
       * @return {number} Auto interval for cateogry axis tick and label
       */
      calculateCategoryInterval: function () {
          var axis = this;
          var labelModel = axis.getLabelModel();
  
          var ordinalScale = axis.scale;
          var ordinalExtent = ordinalScale.getExtent();
          // Providing this method is for optimization:
          // avoid generating a long array by `getTicks`
          // in large category data case.
          var tickCount = ordinalScale.count();
  
          if (ordinalExtent[1] - ordinalExtent[0] < 1) {
              return 0;
          }
  
          var tickValue = ordinalExtent[0];
          var unitSpan = axis.dataToCoord(tickValue + 1) - axis.dataToCoord(tickValue);
          var unitH = Math.abs(unitSpan);
  
          // Not precise, just use height as text width
          // and each distance from axis line yet.
          var rect = textContain.getBoundingRect(
              tickValue, labelModel.getFont(), 'center', 'top'
          );
          var maxH = Math.max(rect.height, 7);
  
          var dh = maxH / unitH;
          // 0/0 is NaN, 1/0 is Infinity.
          isNaN(dh) && (dh = Infinity);
          var interval = Math.max(0, Math.floor(dh));
  
          var cache = inner(axis.model);
          var lastAutoInterval = cache.lastAutoInterval;
          var lastTickCount = cache.lastTickCount;
  
          // Use cache to keep interval stable while moving zoom window,
          // otherwise the calculated interval might jitter when the zoom
          // window size is close to the interval-changing size.
          if (lastAutoInterval != null
              && lastTickCount != null
              && Math.abs(lastAutoInterval - interval) <= 1
              && Math.abs(lastTickCount - tickCount) <= 1
              // Always choose the bigger one, otherwise the critical
              // point is not the same when zooming in or zooming out.
              && lastAutoInterval > interval
          ) {
              interval = lastAutoInterval;
          }
          // Only update cache if cache not used, otherwise the
          // changing of interval is too insensitive.
          else {
              cache.lastTickCount = tickCount;
              cache.lastAutoInterval = interval;
          }
  
          return interval;
      }
  };
  
  zrUtil.inherits(AngleAxis, Axis);
  
  export default AngleAxis;