Binding a Shape class to the StackPane height - javafx

Question

Scenario : A Stage contains a Scene.The Scene contains a StackPane. The height and width of the StackPane and Scene are bind together. The StackPane contains a Shape which is a union of Rectangle and Shape.
Issue - I am facing issue while binding a Shape class to the height of StackPane. How to bind a particular part of Shape class or the complete Shape class in my example?
Requirement - I have 2 requirements.
When I maximize the stage, the StackPane gets increased since the
height and width are bind to Scene but the Shape doesnt increase. I
need both the Shape's(smallShape and bigRectangle) to increase
in terms of height only.
When I maximize the stage the StackPane should increase as well as only the bigger rectangle height should increase but not the other small rectangle i.e bigRectangle height should increase only.
Below is my code snippet
package application;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.RectangleBuilder;
import javafx.scene.shape.Shape;
import javafx.stage.Stage;
public class BindingShape extends Application {
#Override
public void start(Stage primaryStage) throws Exception {
StackPane stackPane = new StackPane();
stackPane.setPrefHeight(200);
stackPane.setPrefWidth(200);
stackPane.setStyle("-fx-background-color: BEIGE");
Shape smallShape = RectangleBuilder.create()
.x(0)
.y(3)
.arcWidth(6)
.arcHeight(6)
.width(50) // allow overlap for union of tab and content rectangle
.height(50)
.build();
Rectangle bigRectangle = RectangleBuilder.create()
.x(25)
.y(0)
.arcWidth(10)
.arcHeight(10)
.width(100)
.height(100)
.build();
Shape unionShape = Shape.union(smallShape, bigRectangle);
unionShape.setFill(Color.rgb(0, 0, 0, .50));
unionShape.setStroke(Color.BLUE);
Group shapeGroup = new Group();
shapeGroup.getChildren().add(unionShape);
stackPane.getChildren().add(shapeGroup);
Group paneGroup = new Group();
paneGroup.getChildren().add(stackPane);
Scene scene = new Scene(paneGroup, 400, 400,Color.LIGHTSKYBLUE);
stackPane.prefHeightProperty().bind(scene.heightProperty().divide(2));
stackPane.prefWidthProperty().bind(scene.widthProperty().divide(2));
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
Please let me know the solution. Thanks in advance.

Answer 1

As the union cannot be resized in parts, I would rebuild the union if the container has been resized like in:
public class BindStackPaneToScene extends Application {
Shape union;
Shape makeShape(double w, double h) {
Rectangle smallShape = new Rectangle(0, 3, 50, 50);
smallShape.setArcHeight(6);
smallShape.setArcWidth(6);
Rectangle bigRectangle = new Rectangle(25, 3, w/2, h/2);
bigRectangle.setArcHeight(10);
bigRectangle.setArcWidth(10);
Shape unionShape = Shape.union(smallShape, bigRectangle);
unionShape.setFill(Color.rgb(0, 0, 0, .50));
unionShape.setStroke(Color.BLUE);
return unionShape;
}
#Override
public void start(Stage primaryStage) throws Exception {
StackPane stackPane = new StackPane();
stackPane.setPrefHeight(200);
stackPane.setPrefWidth(200);
stackPane.setStyle("-fx-background-color: BEIGE");
union = makeShape(200,200);
Group shapeGroup = new Group();
shapeGroup.getChildren().add(union);
stackPane.getChildren().add(shapeGroup);
stackPane.heightProperty().addListener((p, o, n) -> {
if (union != null) shapeGroup.getChildren().remove(union);
union = makeShape(stackPane.getWidth(), n.doubleValue());
shapeGroup.getChildren().add(union);
});
Group paneGroup = new Group();
paneGroup.getChildren().add(stackPane);
Scene scene = new Scene(paneGroup, 400, 400,Color.LIGHTSKYBLUE);
stackPane.prefHeightProperty().bind(scene.heightProperty().divide(1));
stackPane.prefWidthProperty().bind(scene.widthProperty().divide(1));
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}