<Swing Dev> Background/Foreground colors and Gtk Look and Feel

[Joel Uckelman]

Thus spake Alexander Potochkin:
> Hello Gentlemen
> 
> The truth is that L&F can completely ignore the background and 
> foreground properties
> 
> see JComponent.setBackground() javadoc:
> 
>       * It is up to the look and feel to honor this property, some may
>       * choose to ignore it.
> 
> So for reliable implementation I'd recommend to choose another technique
> 
> You may be interested in this blog
> http://polygoncell.blogspot.com/2008/07/validation-module-for-swing-applicati
> on.html
> 
> Thanks
> alexp
 
Thanks for the reply, but the technique in the blog post seems only to
show how you'd decorate a component of type X which is being used as
in the role of a component of type X. It doesn't address at all the
problem of using a component of type Y in the role of a component of
type X.

The concrete problem I faced was that I needed a label which would have
fully-justified text that would reflow when resized. So far as I was
able to tell, there is no way to do this with JLabel. On the other hand,
it's not terribly hard to subclass a JTextPane to get the text behavior
I want. However, then I have the problem that a JTextPane doesn't look
like a JLabel in some LAFs. I thought that I could overcome this by 
getting the foreground and background colors for JLabel from UIManager,
and then setting those on my custom JTextPane. But setBackground() isn't
guaranteed to work in all LAFs, and it just happens that the one LAF
where I absolutely want it to work (GTK) is one where it doesn't.

What I see as the fundamental problem here is that component classes
and component roles are treated as identical. It should be possible
to tell Swing that component X has the role Label, and therefore paint
it like one. This should not depend on component X being a JLabel, as
that ties the role to the implementation.

Am I making sense here? I still don't see my way through this.

-- 
J.