Color gradients lib

["Alex R. Mosteo" <alejandro@mosteo.invalid>]

Hello,

I need to plot some data (2D maps) and I have everything in my drawing 
library except some readily usable gradients. I was wondering if some Ada 
library out there has this before making my custom one.

I would need one to represent bad/good ranges (e.g. the default gradient 
blue-cold to red-hot in matlab), and another to show a density of samples 
(perhaps simple shades of gray).

The second one is straightforward, but the first one seems like something 
pretty standard, so I wouldn't like to create one that is similar but not 
the same.

(e.g. the first example in 
http://www.mathworks.com/help/techdoc/visualize/f0-18164.html#f0-5919 )

Thanks for any suggestions.