Re: [cp-patches] FYI: MetalIconFactory.getRadioButtonMenuItemIcon()

[David Gilbert]

Tom Tromey wrote:

> On Tue, 2005-08-30 at 21:35 +0000, David Gilbert wrote:
>  
>
> > I committed this patch to add an icon for JRadioButtonMenuItems under the Metal look 
> > and feel:
> >    
>
>  
>
> > +    public int getIconWidth() 
> > +    {
> > +      return 10;
> > +    }
> >    
>
> I notice there are an awful lot of constant integers in the plaf code.
> My reflex is to say that these ought to be given a name somewhere,
> so that we can more easily change them later if need be -- particularly
> if we know that, say, many of the "2"s are actually "METAL_BORDER_WIDTH"
> or the like, if you catch my meaning.  What do you think?
>
> Tom
>
>  
I'll keep a look out for anything that might need a named constant.  The 
particular example you mentioned shouldn't cause a problem, because this 
is the value that matches Sun's JDK and it is covered with a Mauve test 
(not sure if I checked in all my icon dimension tests yet, but I will).  
The value will never change (it is a 10x10 icon, forever).

But as I start to dig deeper into the look and feel code, I'm sure there 
will be some magic values for which your comment is spot on.  Very 
likely in the layout code which I haven't dug into very far yet.

The icon drawing code is another area where there are lots of constants, 
for example:

     g.drawLine(x + 2, y, x + 6, y);
     g.drawLine(x + 7, y + 1, x + 7, y + 1);
     g.drawLine(x + 8, y + 2, x + 8, y + 6);
     g.drawLine(x + 7, y + 7, x + 7, y + 7);
     g.drawLine(x + 2, y + 8, x + 6, y + 8);
     g.drawLine(x + 1, y + 7, x + 1, y + 7);
     g.drawLine(x, y + 2, x, y + 6);
     g.drawLine(x + 1, y + 1, x + 1, y + 1);

Icons get *drawn* this way in the MetalLookAndFeel, rather than 
displaying a PNG image for example, so that the icon can change 
appearance when (a) the component state changes and (b) the Metal theme 
(primarily colors) is changed (less common).  There are no state changes 
in the fragment above, but take a look through MetalIconFactory.java if 
you are interested.  The constants are just offsets from the top-left 
corner of the icon, and won't change as long as we are replicating the 
icons from the Metal look and feel.

Regards,

Dave