[R] [FORGED] creating a color gradient in geom_ribbon

[Paul Murrell]

Hi

If the ribbon has constant "height" then this can be hacked by drawing a 
bunch of ribbons (polygons) with different heights and slowly changing 
colours.  If the height of the ribbon varies, then you could use the 
same approach and clip the result, with a little bit more work.  The 
attached code demonstrates the latter approach (the image files that it 
produces for me are also attached).

Hope that helps

Paul

On 11/05/17 08:05, Kristi Glover wrote:
> Hi R Users,
>
> I was trying to create a figure with geom_ribbon. There is a function
> "fill", but I want to make the shaded area with a gradient
> (increasing dark color towards a central line, inserted of having a
> color). Is there any possibility?
>
>
> In the given example, I want the colour with "blue" but in a gradient
> (dark=central, light= as goes higher or lower)
>
>
> pl = data.frame(Time = 0:10, menle = rnorm(11))
>
> pl$menlelb = pl$menle -1
>
> pl$menleub = pl$menle +1
>
> ggplot(pl, aes(Time)) +
>
> geom_line(aes(y=menle), colour="blue") +
>
> geom_ribbon(aes(ymin=menlelb, ymax=menleub), fill="blue")
>
>
> Thanks
>
> [[alternative HTML version deleted]]
>
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-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
paul at stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/
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