Property binding for size produces wrong results on size change

Question

Hi,
I've a small class extending from BorderPane. This class contains a simple Rectangle whichs size is bound to the size of the BorderPane minus 20:
package com.example;
import javafx.scene.layout.BorderPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
public class InnerBorder extends BorderPane {
    private Rectangle r = null;
    public InnerBorder() {
        this.r = new Rectangle();
        r.widthProperty().bind(this.widthProperty().subtract(20));       
        r.heightProperty().bind(this.heightProperty().subtract(20));
        r.setStrokeWidth(0.5f);
        r.setFill(null);
        r.setStroke(Color.BLACK);
        this.setCenter(r);
}Used in a small application:
package com.example;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
public class Example extends Application {
    public static void main(String[] args) {
        launch(args);
    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("Hello World!");               
        BorderPane root = new BorderPane();       
        root.setCenter(new InnerBorder());
        primaryStage.setScene(new Scene(root, 300, 250));
        primaryStage.show();
}When I change the size of the window, the size of the rectangle changes also. But the result looks a little bit strange. When a change the size too fast, the size of the rectangle will not be changed correctly. The rectangle will became larger than the window and is then, of course, not longer visible. Changing then the window a little bit slower will again result in a correct rectangle. Until the next too fast window size changing.
Is there anything wrong on my code?
When I use the same implementation (property binding) in a Control with a Skin, the result is even more strange. If the subtract is too small (< ~40), the size grows endless. Of course the window size doesnt grows, but the property value grows on every size change, even if the window will be smaller. This code is a little bit more, so I will post it if no one could show me an error in my sourcecode above.
Kind regards

Answer 1

Hi. I did some modifications. Now it looks OK.
import javafx.scene.layout.BorderPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
public class InnerBorder extends BorderPane {
   // private Rectangle r = null;
    public Rectangle r = null;
    public InnerBorder() {
        this.r = new Rectangle();
       // r.widthProperty().bind(this.widthProperty().subtract(20));       
       // r.heightProperty().bind(this.heightProperty().subtract(20));
        r.setStrokeWidth(0.5f);
        r.setFill(null);
        r.setStroke(Color.BLACK);
        this.setCenter(r);
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
public class Example extends Application {
    public static void main(String[] args) {
        launch(args);
    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("Hello World!");               
        BorderPane root = new BorderPane(); 
        InnerBorder inb = new InnerBorder();
        inb.r.widthProperty().bind(root.widthProperty().subtract(20)); 
        inb.r.heightProperty().bind(root.heightProperty().subtract(20));
        root.setCenter(inb);
        primaryStage.setScene(new Scene(root, 300, 250));
        primaryStage.show();
}