JFXPanel ignores size change of root node

Werner Lehmann lehmann at media-interactive.de
Mon Dec 17 03:59:29 PST 2012

Hi Artem,

On 17.12.2012 12:09, Artem Ananiev wrote:
> Just imagine the following scenario. Create a regular FX Stage and put a
> 120x120 button inside. Then show the stage. Then set an action listener
> to the button, so it changes the button size to 160x120. Will the stage
> size change, when the button is clicked?

coincidentally I tried that while you were typing up that email. The 
stage does not resize. Inspection in a breakpoint shows that also the 
scene.width does not change. So how would the stage know about it anyway...

> Could you try to leave JFXPanel as is, but set its scene to null and
> back to your scene, please? I don't say it's the way it's supposed to
> work, just an idea for workaround.

This works - sometimes. If I keep clicking that button I get about 70% 
correct results and occasionally the JFXPanel did not resize as desired. 
Here's the kicker: sleeping for 10ms after setting the scene works 
reliably (on my machine and for this simple scene). 9ms is not enough:

           r.setWidth(r.getWidth() == 160 ? 120 : 160);
           Scene scene = getScene();

Not exactly reassuring but better than before. Alternatively, the sleep 
can be moved to the EDT which also works:

           r.setWidth(r.getWidth() == 160 ? 120 : 160);
           Scene scene = getScene();
           SwingUtilities.invokeLater(new Runnable() {
             public void run()

Some kind of strange race condition? Obviously I'd like to avoid any 
hardcoded sleeps... Also: am I supposed to invalidate on EDT, or not? 
Seems to work without.

> In general, updating JFXPanel's preferred size upon FX scene
> size/content changes looks like a valid request. It's not a pure
> JFXPanel feature, though: we need to have a notification from Scene to
> know that the window size should be updated.

Scene has observable width/height properties. Not sure if those change 
but at least Scene.root.*anyboundsproperty* should do.


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