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node_modules/echarts/src/chart/helper/EffectPolyline.js 3.47 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.
  */
  
  /**
   * Provide effect for line
   * @module echarts/chart/helper/EffectLine
   */
  
  import Polyline from './Polyline';
  import * as zrUtil from 'zrender/src/core/util';
  import EffectLine from './EffectLine';
  import * as vec2 from 'zrender/src/core/vector';
  
  /**
   * @constructor
   * @extends {module:echarts/chart/helper/EffectLine}
   * @alias {module:echarts/chart/helper/Polyline}
   */
  function EffectPolyline(lineData, idx, seriesScope) {
      EffectLine.call(this, lineData, idx, seriesScope);
      this._lastFrame = 0;
      this._lastFramePercent = 0;
  }
  
  var effectPolylineProto = EffectPolyline.prototype;
  
  // Overwrite
  effectPolylineProto.createLine = function (lineData, idx, seriesScope) {
      return new Polyline(lineData, idx, seriesScope);
  };
  
  // Overwrite
  effectPolylineProto.updateAnimationPoints = function (symbol, points) {
      this._points = points;
      var accLenArr = [0];
      var len = 0;
      for (var i = 1; i < points.length; i++) {
          var p1 = points[i - 1];
          var p2 = points[i];
          len += vec2.dist(p1, p2);
          accLenArr.push(len);
      }
      if (len === 0) {
          return;
      }
  
      for (var i = 0; i < accLenArr.length; i++) {
          accLenArr[i] /= len;
      }
      this._offsets = accLenArr;
      this._length = len;
  };
  
  // Overwrite
  effectPolylineProto.getLineLength = function (symbol) {
      return this._length;
  };
  
  // Overwrite
  effectPolylineProto.updateSymbolPosition = function (symbol) {
      var t = symbol.__t;
      var points = this._points;
      var offsets = this._offsets;
      var len = points.length;
  
      if (!offsets) {
          // Has length 0
          return;
      }
  
      var lastFrame = this._lastFrame;
      var frame;
  
      if (t < this._lastFramePercent) {
          // Start from the next frame
          // PENDING start from lastFrame ?
          var start = Math.min(lastFrame + 1, len - 1);
          for (frame = start; frame >= 0; frame--) {
              if (offsets[frame] <= t) {
                  break;
              }
          }
          // PENDING really need to do this ?
          frame = Math.min(frame, len - 2);
      }
      else {
          for (var frame = lastFrame; frame < len; frame++) {
              if (offsets[frame] > t) {
                  break;
              }
          }
          frame = Math.min(frame - 1, len - 2);
      }
  
      vec2.lerp(
          symbol.position, points[frame], points[frame + 1],
          (t - offsets[frame]) / (offsets[frame + 1] - offsets[frame])
      );
  
      var tx = points[frame + 1][0] - points[frame][0];
      var ty = points[frame + 1][1] - points[frame][1];
      symbol.rotation = -Math.atan2(ty, tx) - Math.PI / 2;
  
      this._lastFrame = frame;
      this._lastFramePercent = t;
  
      symbol.ignore = false;
  };
  
  zrUtil.inherits(EffectPolyline, EffectLine);
  
  export default EffectPolyline;