en/builder/src/echarts3/chart/helper/LinePath.js

/**
 * Line path for bezier and straight line draw
 */
import * as graphic from '../../util/graphic';
import * as vec2 from 'zrender/src/core/vector';
var straightLineProto = graphic.Line.prototype;
var bezierCurveProto = graphic.BezierCurve.prototype;

function isLine(shape) {
  return isNaN(+shape.cpx1) || isNaN(+shape.cpy1);
}

export default graphic.extendShape({
  type: 'ec-line',
  style: {
    stroke: '#000',
    fill: null
  },
  shape: {
    x1: 0,
    y1: 0,
    x2: 0,
    y2: 0,
    percent: 1,
    cpx1: null,
    cpy1: null
  },
  buildPath: function (ctx, shape) {
    (isLine(shape) ? straightLineProto : bezierCurveProto).buildPath(ctx, shape);
  },
  pointAt: function (t) {
    return isLine(this.shape) ? straightLineProto.pointAt.call(this, t) : bezierCurveProto.pointAt.call(this, t);
  },
  tangentAt: function (t) {
    var shape = this.shape;
    var p = isLine(shape) ? [shape.x2 - shape.x1, shape.y2 - shape.y1] : bezierCurveProto.tangentAt.call(this, t);
    return vec2.normalize(p, p);
  }
});