在StackPane中缩放Text和ImageView组

Question

我需要获取上面的图片和文字。我创建了StackPane并将ImageView和Group中的Text元素放在里面。我想调整StackPane的大小，并将ImageView比例和文本组的位置保持在此ImageView上。下面的代码有效，但是当我调整StackPane的大小时，我无法修复文本组的位置。

小窗口。图像顶部的文字顶部

大窗口。低于图像顶部的文本顶部

public class SlideFromText extends Slide {

    private StackPane sp = new StackPane();
    private ImageView iv = new ImageView();
    private Group text_group = new Group();

    public SlideFromText(Image img, String text_string) {

        iv.setImage(img);
        iv.setPreserveRatio(true);
        iv.fitWidthProperty().bind(sp.widthProperty());
        iv.fitHeightProperty().bind(sp.heightProperty());

        sp.setAlignment(Pos.TOP_CENTER);
        sp.setMinSize(0, 0);
        sp.getChildren().add(iv);

        String lines[] = text_string.split("\\r?\\n");
        double height = 0;
        double maxWidth = 0;
        String font_name = (String) Options.getOption("font");
        Font f = new Font(font_name, 20);
        ArrayList<Text> text_array = new ArrayList<>();

        for (String line : lines) {
            Text text = new Text(line);
            text.setFont(f);
            text.setFill(Color.WHITE);
            text.setTextOrigin(VPos.BASELINE);
            text.setTextAlignment(TextAlignment.CENTER);
            DropShadow sh = new DropShadow(3, Color.BLACK);
            sh.setSpread(0.25);
            text.setEffect(sh);
            height += text.getBoundsInParent().getHeight();
            text.setY(height);
            text.setX(sh.getRadius() / 2);
            maxWidth = Math.max(maxWidth, text.getBoundsInParent().getWidth());
            text_array.add(text);
        }

        for (Text t : text_array) {
            t.setWrappingWidth(maxWidth);
        }

        text_group.getChildren().addAll(text_array);

        sp.getChildren().add(text_group);
        iv.boundsInParentProperty().addListener(new ChangeListener<Bounds>() {
            @Override
            public void changed(ObservableValue<? extends Bounds> observable, Bounds oldValue, Bounds newValue) {

                Node node = sp.getChildren().get(1);
                if (node.getClass() != Group.class) {
                    return;
                }

                Group group_node = (Group) node;

                group_node.setLayoutX(-1.0 * group_node.layoutBoundsProperty().get().getWidth() / 2.0);
                group_node.getTransforms().clear();

                double scale_x = (iv.getBoundsInParent().getWidth() * 0.95) / group_node.getBoundsInParent().getWidth();
                double scale_y = (iv.getBoundsInParent().getHeight() * 0.95) / group_node.getBoundsInParent().getHeight();
                double scale_factor = Math.min(scale_x, scale_y);

                double pivot_x = (group_node.getBoundsInLocal().getMaxX() - group_node.getBoundsInLocal().getMinX()) / 2;
                Scale scale = new Scale(scale_factor, scale_factor, pivot_x, 0);
                group_node.getTransforms().add(scale);
            }

        });
    }

    @Override
    public Pane getPane() {
        return sp;
    }

}