code: private Transition getShowAnimation(DialogTransition transitionType) {
          Transition animation = null;
          if (contentHolder != null) {
              switch (transitionType) {
                  case LEFT:
                      contentHolder.setScaleX(1);
                      contentHolder.setScaleY(1);
                      contentHolder.setTranslateX(-offsetX);
                      animation = new LeftTransition();
                      break;
                  case RIGHT:
                      contentHolder.setScaleX(1);
                      contentHolder.setScaleY(1);
                      contentHolder.setTranslateX(offsetX);
                      animation = new RightTransition();
                      break;
                  case TOP:
                      contentHolder.setScaleX(1);
                      contentHolder.setScaleY(1);
                      contentHolder.setTranslateY(-offsetY);
                      animation = new TopTransition();
                      break;
                  case BOTTOM:
                      contentHolder.setScaleX(1);
                      contentHolder.setScaleY(1);
                      contentHolder.setTranslateY(offsetY);
                      animation = new BottomTransition();
                      break;
                  case CENTER:
                      contentHolder.setScaleX(0);
                      contentHolder.setScaleY(0);
                      animation = new CenterTransition();
                      break;
                  default:
                      animation = null;
                      contentHolder.setScaleX(1);
                      contentHolder.setScaleY(1);
                      contentHolder.setTranslateX(0);
                      contentHolder.setTranslateY(0);
                      break;
              }
          }
          if (animation != null) {
              animation.setOnFinished(finish ->
                  Event.fireEvent(JFXDialog.this, new JFXDialogEvent(JFXDialogEvent.OPENED)));
          }
          return animation;
      }
docs: *************************************************************************
  *
  Transitions                                                             *
  *
  ************************************************************************