@Nonnull
  @CheckReturnValue
  public SizeDouble getSubtracted(@Nonnull final IHasDimensionDouble aToSubtract) {
    ValueEnforcer.notNull(aToSubtract, "ToSubtract");

    return new SizeDouble(m_dWidth - aToSubtract.getWidth(), m_dHeight - aToSubtract.getHeight());
  }
  @Nonnull
  @CheckReturnValue
  public SizeDouble getAdded(@Nonnull final IHasDimensionDouble aToAdd) {
    ValueEnforcer.notNull(aToAdd, "ToAdd");

    return new SizeDouble(m_dWidth + aToAdd.getWidth(), m_dHeight + aToAdd.getHeight());
  }
 public SizeDouble(@Nonnull final IHasDimensionDouble aObj) {
   this(aObj.getWidth(), aObj.getHeight());
 }