Re: [Matplotlib-users] 'Inverting' a colormap (was "Next problem: pixel-to-pixel alpha variation")

[David G. <d_l...@ya...>]

Excellent, thanks!!!

DG
--- On Tue, 9/16/08, John Hunter <jd...@gm...> wrote:

> From: John Hunter <jd...@gm...>
> Subject: Re: [Matplotlib-users] 'Inverting' a colormap (was "Next problem: pixel-to-pixel alpha variation")
> To: d_l...@ya...
> Cc: mat...@li...
> Date: Tuesday, September 16, 2008, 12:46 PM
> On Tue, Sep 16, 2008 at 2:40 PM, David Goldsmith
> <d_l...@ya...> wrote:
> > --- On Tue, 9/9/08, David Goldsmith
> <d_l...@ya...> wrote:
> >
> >> eventually ... I'd like to do what John
> implies
> >> is possible, i.e., "invert" a cm back to
> its RGB
> >> table - John (or anyone) can you short-cut the
> learning
> >> process for me w/ a code example of how to do
> this? :-)
> >> Thanks!
> >>
> >> DG
> >
> > No one has a shareable code example of how to invert a
> colormap to an RGB array?
> 
> Is this what you are looking for?  (outputs RGBA but just
> override the
> alpha or extract the RGB part)
> 
> 
> >In [9]: import matplotlib.cm as cm
> 
> In [10]: x = np.arange(0, 1, 0.1)
> 
> In [11]: print cm.jet(x)
> [[ 0.          0.          0.5         1.        ]
>  [ 0.          0.          0.9456328   1.        ]
>  [ 0.          0.3         1.          1.        ]
>  [ 0.          0.69215686  1.          1.        ]
>  [ 0.16129032  1.          0.80645161  1.        ]
>  [ 0.49019608  1.          0.47754586  1.        ]
>  [ 0.80645161  1.          0.16129032  1.        ]
>  [ 1.          0.77051561  0.          1.        ]
>  [ 1.          0.40740741  0.          1.        ]
>  [ 0.9456328   0.02977487  0.          1.        ]]