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

[Mike Swingler]

On Jan 22, 2009, at 3:12 AM, Kirill Kirichenko wrote:

> Hi Omar
> Sorry for delay from out side.
> I'm a responsible engineer for GTK L&F.
>
> Omair Majid wrote:
>
>> I have noticed a few issues in the Gtk Look and Feel and would like  
>> to know what the correct behaviour should be. The attached program  
>> shows a few of my concerns.
>> 1) For each of the components, setForeground(color) and/or  
>> setBackground(color) assignments are randomly ignored. Is this the  
>> expected behaviour? I can understand that using the native look and  
>> feel, the feel is exactly preserved and the programmer's  
>> preferences are ignored. But there doesn't seem to be any  
>> consistency - some components accept the color changes, some  
>> silently ignore it. Is there a list showing whether setForeground()  
>> and setBackground() is ignored for each swing component with the  
>> gtk look and feel?
>
> Generally GTK L&F leverages theme settings for colors, indents and  
> fonts. And you shouldn't be able to change them using standard swing  
> API when GTK L&F is active. Sometimes this does work but you  
> shouldn't use this feature. This is the policy for GTK L&F. Actually  
> the have been similar requests and I tried to resolve the issue. The  
> thing is GTK itself doesn't allow changing colors freely for all  
> components it just uses the theme settings.

This is basically the policy of the Aqua Look and Feel on Mac OS X as  
well. Sometimes we do pick up the foreground/background colors for  
some controls where it makes sense, or the TCK requires us to, but  
generally, we use our own system artwork to draw these controls.

Not every component (particularly non-rectangular ones) have a good  
sense of what a "background" color is. Also, on Mac OS X, we are  
particularly sensitive to allowing developers to create rainbow  
kaleidoscope apps that clash with the rest of the Mac OS X desktop  
experience, and try to make Java apps that have not necessarily tested  
on our platform still look like Mac apps.

>> 2) The behaviour varies across jdk6 and openjdk6. For example, the  
>> closed-source jdk6 respects  
>> JTextPane.setBackground(UIManager.getColor("Panel.background")) but  
>> openjdk6 ignores it. In situations like this, what is the correct  
>> behaviour? Should I attempt to patch openjdk6 to behave more like  
>> closed source jdk6?
>
> It may happen because the codebases slightly different. I haven't  
> applied all fixes to openjdk6 which I have to jdk6.
>
> Hope that helps.

Cheers,
Mike Swingler
Java Runtime Engineer
Apple Inc.