anchor.diff:              assert(result.r >= 0 && result.r <= 255);
               assert(result.g >= 0 && result.g <= 255);
               assert(result.b >= 0 && result.b <= 255);
  -            newColors[i * 4 + 0] = result.r;
  -            newColors[i * 4 + 1] = result.g;
  -            newColors[i * 4 + 2] = result.b;
  -            newColors[i * 4 + 3] = 255;
  +            rgba[i * 4 + 0] = result.r;
  +            rgba[i * 4 + 1] = result.g;
  +            rgba[i * 4 + 2] = result.b;
  +            rgba[i * 4 + 3] = 255;
           }
  -
  -        return newColors;
       }
   
       _Color _interpolate(double z, double startRange, double endRange, _Color startColor, _Color endColor) {
  
positive.code:         _rampName = name;
      }
  
      Uint8List _execute(PointCloudTile tile, double zmin, double zmax) {
          if (rampName == null || rampName.isEmpty) {
              throw new StateError("color ramp is null");
          }
  
          // TODO: reuse this every tile
          var newColors = new Uint8List(tile.numPointsInTile * 4);
  
          if (rampName == "native") {
              log(tile.data.keys);
  
negative.code: 
          PointCloud cloud = tile.cloud;
  
          _execute(tile, cloud.bbox.minimum.height, cloud.bbox.maximum.height);
  
          tile.updateBounds();
          tile.updateShape();
      }
  