code: function _getSegmentPoints(segment) {
    var points = [];
    switch (segment[0]) {
      case 'M':
        points.push([segment[1], segment[2]]);
        break;
      case 'L':
        points.push([segment[1], segment[2]]);
        break;
      case 'A':
        points.push([segment[6], segment[7]]);
        break;
      case 'Q':
        points.push([segment[3], segment[4]]);
        points.push([segment[1], segment[2]]);
        break;
      case 'T':
        points.push([segment[1], segment[2]]);
        break;
      case 'C':
        points.push([segment[5], segment[6]]);
        points.push([segment[1], segment[2]]);
        points.push([segment[3], segment[4]]);
        break;
      case 'S':
        points.push([segment[3], segment[4]]);
        points.push([segment[1], segment[2]]);
        break;
      case 'H':
        points.push([segment[1], segment[1]]);
        break;
      case 'V':
        points.push([segment[1], segment[1]]);
        break;
      default:
  
    }
    return points;
  }
docs: /*
  抽取pathSegment中的关键点
  M,L,A,Q,H,V一个端点
  Q, S抽取一个端点，一个控制点
  C抽取一个端点，两个控制点