Hi Ian,

>> thanks for your answer.
>> I am writing to you directly,

>Best not - I very seldom reply to off-list posts...
Sorry, will post to the list.

> OK: Then you need to composite the bar graph on top of the image.
> Fltk does not provide support for transparent widgets (yet) as it is a hard 
> thing to do in a consistent cross-platform way, so the best bet may be for 
> you to just blit the image into the box, then render the bar on top of it.
> This is easy and cheap to do, if you are rendering the graph on top of an 
> image your app "owns".
> If you want to render the graph transparently on top of (for example) the 
> desktop then you are on your own out there, since fltk can't really do that 
> without a lot of platform specific code...!
> Hope that made sense!
> FWIW, I think Greg's cheat pages have examples of doing some of this, so it 
> would be worth a look...
> http://www.seriss.com/people/erco/fltk/ 

I need a bit of thinking.
I am writing an app for creating supervision screens on an embedded platform.
All is ruled by a configuration text file : it is parsed from my program which 
then creates all the pages, the buttons for page jumps, the graphics objects 
and so on.

In general I do not know what there will be under my bargraph : maybe a 
picture, maybe a filled background.
The situation is more similar to the desktop you mentioned.

For now the simplest solution I can imagine is to redraw the whole parent of my 

Thanks a lot for your observations,


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