如何使用carto mobile(carto-SDK)在ios中旋转位置标记

以下代码应起作用,并将图像保持在精确位置:

    NTMarkerStyleBuilder *builder = [[NTMarkerStyleBuilder alloc]init];

    // anchor 0,0 means that image is rotated from the center
    // you may have different anchor point depending on graphics
    [builder setAnchorPointX:0 anchorPointY:0];

    self.positionMarker = [[NTMarker alloc] initWithPos:position style:[builder buildStyle]];

   ...
   // rotate marker, depending on marker graphics
   // "180-course" is ok if it is "arrow down"
   // additional adjustment is for mapView rotation, image keeps
   // here correct course even if map is rotated

  double course = location.course;
  [self.positionMarker setRotation: 180 - course - self.contentView.mapView.getRotation];