Re: gnome-panel transparency problems

[Bill Haneman <Bill Haneman Sun COM>]

> Hey, I have a proposal! (have thought about this for a LOOONG time):
>
> For areas in applets that contain text (clock applet, window list applet, etc),
> check the RGB value of the pixels in the background area;
>
> (example for 8-bit color depth)
> if the average RGB value < 128
>   draw text in white
> else
>   draw text in black
>  

This sounds like a potentially big theming violation to me.
Applets need to use the GTK+ style information when drawing both text 
and graphics, otherwise they violate accessibility requirements.  This 
doesn't mean that you can't have transparent applets, but it does mean 
that their text needs to use the current GTK+ style foreground.

To really do a reasonable job at this while maintaining 
theme/accessibility support, stuff like panel pixmaps need to get rolled 
into the system theme; trying to build a heuristic is contrary to the 
accessibility requirements.

- Bill

> There are two possible approaches:
> 1) check per-applet
> 2) check per-character
>
> Approach 1 is of course faster, but does not handle backgrounds with a lot of
> shifting nuances very well.
> Approach 2 is safe in this manner, but requires a lot more calculation. 
>
> Some sampling approach could work as well (eg check every 2nd/4th/Nth pixel).
>
> Of course, there should be an option in the panel properties: ("Font color:
> [x]automatic [x]manual <choose..>") If "automatic" mode is chosen, there could
> be an secondary option for what method to use - "[x]fail-safe [x]fast"
>
> Note: I think it would look best if the applet bevels etc also used the same
> foreground color.
>
> This could turn out *nice* (did some mockups some time ago, think I have them
> somewhere)
>
> Regards,
> Mikael.
>
>
> -------------------------------------------------