suggestion for transparent colour in shaded-plots

[Goodson,Ron [Edm]]

Just a suggestion -- any chance of adding the ability to designate a
colour number as transparent when doing "gxout shaded" plots?
 
I know you can set the lowest shade to the background colour so it
"looks" like nothing is being drawn (even though it is).  But that
doesn't help when you want to have two separately shaded parameters
(each between some limits so that neither cover the entire graphic)...
as drawing the 2nd parameter overwrite the first.
 
I currently do this by using maskout() to control what is valid data to
draw.  But that leaves big-jagged edges based upon the resolution of my
grid so is neither accurate, nor visually appealing (understandable as I
see maskout as being more for calculations/analysis than for display)
 
If a colour could be marked as transparent - then I could use that for
the colour of my lower/upper limits of my shaded area and be able to
smoothly overlay 2 different shaded areas.  Perhaps it would simply set
the operation to XOR or something like that?
 
ron
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