docs: private void handleMove(NativeEvent nativeEvent) {
  
          Element imageElem = m_image.getElement();
          int offsetX = ((int)pageX(nativeEvent)) - imageElem.getParentElement().getAbsoluteLeft();
          int offsetY = ((int)pageY(nativeEvent)) - imageElem.getParentElement().getAbsoluteTop();
          if (m_coordinateTransform != null) {
              CmsPoint screenPoint = new CmsPoint(offsetX, offsetY);
              screenPoint = m_region.constrain(screenPoint); // make sure we remain in the screen region corresponding to original image (or crop).
              m_pointWidget.setCenterCoordsRelativeToParent((int)screenPoint.getX(), (int)screenPoint.getY());
              CmsPoint logicalPoint = m_coordinateTransform.transformForward(screenPoint);
              m_focalPoint = logicalPoint;
          }
      }