code: public final void setScaledEdge(final Edge edge) {
          Condition.INSTANCE.ensureNotNull(edge, "The edge may not be null");
          this.scaledEdge = edge;
          requestLayout();
      }
docs: Sets the edge of the image view, which should be scaled in order to ensure, that width and
  height are equal. E.g., if the scaled edge is {@link Edge#VERTICAL}, the height of the image
  view is adapted to fit its width.
  
  @param edge
  The edge, which should be set, as a value of the enum {@link Edge}. The edge may
  either be {@link Edge#HORIZONTAL} or {@link Edge#VERTICAL}