Java SE (Java Platform, Standard Edition)

This here is the essence of a problem with a canvas i have right now

public class Test extends Application

{

public static void main(String[] args)

{

launch(args);

}

@Override

public void start(Stage primaryStage)

{

TabPane tabPane = new TabPane();

Tab tab = new Tab("Tab");

tabPane.getTabs().add(tab);

BorderPane borderPane = new BorderPane();

tab.setContent(borderPane);

MyCanvas canvas = new MyCanvas();

borderPane.setCenter(canvas);

canvas.setWidth(500);

canvas.heightProperty().bind(borderPane.heightProperty());

Scene scene = new Scene(tabPane, 1300, 800);

primaryStage.setScene(scene);

primaryStage.show();

}

class MyCanvas extends Canvas

{

public MyCanvas()

{

  this.widthProperty().addListener(evt -> draw());

  this.heightProperty().addListener(evt -> draw());

}

private void draw()

{

  double width = getWidth();

  double height = getHeight();

  System.out.println(width + ";"+ height);

  GraphicsContext context = getGraphicsContext2D();

  context.clearRect(0, 0, width, height);

  context.setFill(Color.GREENYELLOW);

  context.fillRect(0, 0, width, height);

}

}

}

The interesting line being

canvas.heightProperty().bind(borderPane.heightProperty());

This works only halfway, when the window is getting bigger the draw functions all are called, but when the window gets tinier the draw function is not getting called.

Now I thought maybe I have to go higher in the hierarchy.

canvas.heightProperty().bind(tab.? tab has no heightProperty

One futher?

canvas.heightProperty.bind(tabPane.tabPane.heightProperty());

Now this looks good ( it works when it gets bigger or smaller ), until you realize that it always will be atleast 29 pixel big ( atleast on my system )

The reason being that the header is the missing 29 pixel. But I don't see a way to get the size of the header of the tabPane. Now I could just subtract 29 from the tabPane.heightProperty, but that will only work on my system, it might have a different size on other systems or javafx might change.

I looked up some other ways to get a resizable canvas, but stuff like creating a custom Pane and only putting the canvas in and overriding the layoutChildren method seems more like a hack than a intended solution.

I really would appreciate a way to resize my canvas on demand without going any further than the parent of my canvas ( the borderPane in my case ).