code: private GeometryCoordinateSequenceTransformer getTransformer() {
  		if (unitToPixel == null) {
  			unitToPixel = new GeometryCoordinateSequenceTransformer();
  			unitToPixel.setMathTransform(ProjectiveTransform.create(new AffineTransform(scale, 0, 0, -scale, -scale
  					* panOrigin.x, scale * panOrigin.y)));
  		}
  		return unitToPixel;
  	}
docs: Get transformer to use.
  
  @return transformation to apply