public/zh/builder/src/echarts/chart/helper/EffectLine.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.
*/

/**
 * Provide effect for line
 * @module echarts/chart/helper/EffectLine
 */
import * as graphic from '../../util/graphic';
import Line from './Line';
import * as zrUtil from 'zrender/src/core/util';
import { createSymbol } from '../../util/symbol';
import * as vec2 from 'zrender/src/core/vector';
import * as curveUtil from 'zrender/src/core/curve';
/**
 * @constructor
 * @extends {module:zrender/graphic/Group}
 * @alias {module:echarts/chart/helper/Line}
 */

function EffectLine(lineData, idx, seriesScope) {
  graphic.Group.call(this);
  this.add(this.createLine(lineData, idx, seriesScope));

  this._updateEffectSymbol(lineData, idx);
}

var effectLineProto = EffectLine.prototype;

effectLineProto.createLine = function (lineData, idx, seriesScope) {
  return new Line(lineData, idx, seriesScope);
};

effectLineProto._updateEffectSymbol = function (lineData, idx) {
  var itemModel = lineData.getItemModel(idx);
  var effectModel = itemModel.getModel('effect');
  var size = effectModel.get('symbolSize');
  var symbolType = effectModel.get('symbol');

  if (!zrUtil.isArray(size)) {
    size = [size, size];
  }

  var color = effectModel.get('color') || lineData.getItemVisual(idx, 'color');
  var symbol = this.childAt(1);

  if (this._symbolType !== symbolType) {
    // Remove previous
    this.remove(symbol);
    symbol = createSymbol(symbolType, -0.5, -0.5, 1, 1, color);
    symbol.z2 = 100;
    symbol.culling = true;
    this.add(symbol);
  } // Symbol may be removed if loop is false


  if (!symbol) {
    return;
  } // Shadow color is same with color in default


  symbol.setStyle('shadowColor', color);
  symbol.setStyle(effectModel.getItemStyle(['color']));
  symbol.attr('scale', size);
  symbol.setColor(color);
  symbol.attr('scale', size);
  this._symbolType = symbolType;

  this._updateEffectAnimation(lineData, effectModel, idx);
};

effectLineProto._updateEffectAnimation = function (lineData, effectModel, idx) {
  var symbol = this.childAt(1);

  if (!symbol) {
    return;
  }

  var self = this;
  var points = lineData.getItemLayout(idx);
  var period = effectModel.get('period') * 1000;
  var loop = effectModel.get('loop');
  var constantSpeed = effectModel.get('constantSpeed');
  var delayExpr = zrUtil.retrieve(effectModel.get('delay'), function (idx) {
    return idx / lineData.count() * period / 3;
  });
  var isDelayFunc = typeof delayExpr === 'function'; // Ignore when updating

  symbol.ignore = true;
  this.updateAnimationPoints(symbol, points);

  if (constantSpeed > 0) {
    period = this.getLineLength(symbol) / constantSpeed * 1000;
  }

  if (period !== this._period || loop !== this._loop) {
    symbol.stopAnimation();
    var delay = delayExpr;

    if (isDelayFunc) {
      delay = delayExpr(idx);
    }

    if (symbol.__t > 0) {
      delay = -period * symbol.__t;
    }

    symbol.__t = 0;
    var animator = symbol.animate('', loop).when(period, {
      __t: 1
    }).delay(delay).during(function () {
      self.updateSymbolPosition(symbol);
    });

    if (!loop) {
      animator.done(function () {
        self.remove(symbol);
      });
    }

    animator.start();
  }

  this._period = period;
  this._loop = loop;
};

effectLineProto.getLineLength = function (symbol) {
  // Not so accurate
  return vec2.dist(symbol.__p1, symbol.__cp1) + vec2.dist(symbol.__cp1, symbol.__p2);
};

effectLineProto.updateAnimationPoints = function (symbol, points) {
  symbol.__p1 = points[0];
  symbol.__p2 = points[1];
  symbol.__cp1 = points[2] || [(points[0][0] + points[1][0]) / 2, (points[0][1] + points[1][1]) / 2];
};

effectLineProto.updateData = function (lineData, idx, seriesScope) {
  this.childAt(0).updateData(lineData, idx, seriesScope);

  this._updateEffectSymbol(lineData, idx);
};

effectLineProto.updateSymbolPosition = function (symbol) {
  var p1 = symbol.__p1;
  var p2 = symbol.__p2;
  var cp1 = symbol.__cp1;
  var t = symbol.__t;
  var pos = symbol.position;
  var quadraticAt = curveUtil.quadraticAt;
  var quadraticDerivativeAt = curveUtil.quadraticDerivativeAt;
  pos[0] = quadraticAt(p1[0], cp1[0], p2[0], t);
  pos[1] = quadraticAt(p1[1], cp1[1], p2[1], t); // Tangent

  var tx = quadraticDerivativeAt(p1[0], cp1[0], p2[0], t);
  var ty = quadraticDerivativeAt(p1[1], cp1[1], p2[1], t);
  symbol.rotation = -Math.atan2(ty, tx) - Math.PI / 2;
  symbol.ignore = false;
};

effectLineProto.updateLayout = function (lineData, idx) {
  this.childAt(0).updateLayout(lineData, idx);
  var effectModel = lineData.getItemModel(idx).getModel('effect');

  this._updateEffectAnimation(lineData, effectModel, idx);
};

zrUtil.inherits(EffectLine, graphic.Group);
export default EffectLine;