Re: [Matplotlib-users] switching between color and grayscale

I am making some progress.  The following script works, but you have
to shut down ipython if you want to switch from color to grayscale:

from numpy import arange, sin, cos, pi
import matplotlib.colors
reload(matplotlib.colors)
cnames=3Dmatplotlib.colors.cnames
from pylab import figure, show, nx, clf, cla
fig =3D figure(4)
ax =3D fig.add_subplot(111)
t=3Darange(0,1,0.01)
y=3Dsin(2*pi*t)
grayscale=3D0
if not grayscale: # using color
    cnames['mygreen'] =3D '#008000'
else: # using grayscale
    cnames['mygreen'] =3D '#808080'

#ax.plot(t,y, color=3Dcnames['green'])
ax.plot(t,y, color=3D'mygreen')
show()

Is there some command to refresh the system color dictionary?

Thanks,

Ryan

On 4/17/06, John Hunter <jdh...@ac...> wrote:
> >>>>> "Ryan" =3D=3D Ryan Krauss <rya...@gm...> writes:
>
>     Ryan> I am mildly concerned about how my plots will look if
>     Ryan> someone prints my thesis out in grayscale.  Is there an easy
>     Ryan> way to use the same code with one switch at the beginning to
>     Ryan> plot in color or grayscale?  Is there a way to redefine what
>     Ryan> happens when I call plot(x,y,'g-') so that 'g-' no longer
>     Ryan> means green but now means something like color=3D0.75 so some
>     Ryan> grayscale specification?
>
> That is an interesting problem I hadn't considered before.  We have *a
> lot* of colors defined in matplotlib.colors.  cnames is a dict from
> color names to rgb tuples (see below for example usage).
>
> It would be useful to support custom colors in the rc file or
> elsewhere -- then you could do something like
>
>   colors.mygreen  : 008000
>
> and later redefine it to gray if you need to
>
>   colors.mygreen  : 808080
>
> But you can't do that today...  What you can do is manipulate the
> cnames dict.  I suggest creating a module like mycolors that extends
> the cnames dict, and then using these custom color names in your
> script.  When you want to go grayscale, you just modify the colors in
> mycolors.
>
>
>     # mycolors.py
>     from matplotlib.colors import cnames
>     if 1: # using color
>         cnames['mygreen'] =3D '#008000'
>     else: # using grayscale
>         cnames['mygreen'] =3D '#808080'
>
>
> Then later, you can use it as follows:
>
>     import mycolors
>     from pylab import figure, show, nx
>     fig =3D figure()
>     ax =3D fig.add_subplot(111)
>     ax.plot((1,2,3), color=3D'mygreen')
>     show()
>
> so you'll only have a single point of maintenance.  We'll also accept
> a patch to the rc system to support custom colors, which is the
> preferred way to go.
>
> JDH
>