Re: [matplotlib-devel] [Matplotlib-users] ANN: mpltools 0.1 release

[todd r. <tod...@gm...>]

On Wed, Jul 11, 2012 at 5:23 PM, John Hunter <jd...@gm...> wrote:
>
>
> On Wed, Jul 11, 2012 at 10:09 AM, Damon McDougall
> <dam...@gm...> wrote:
>>
>> Well, as Ben said, that error fill plot is neato! It doesn't look too
>> complicated, either. I'd be more than happy to port it over later today
>> when I get bored of typing up my thesis. It'll probably only take me
>> about 30 minutes.
>>
>> If nobody is opposed to this idea, I'll go ahead and submit a PR this
>> evening (British Summer (hah!) Time).
>
>
>
> While it is a nice graph, I am not sure that the use case is common enough
> to justify a new plotting method.  One can get the same result with:
>
>
>   In [68]: x = np.linspace(0, 2 * np.pi)
>
>   In [69]: y_sin = np.sin(x)
>
>   In [70]: err = np.concatenate([y_sin + 0.2, y_sin[::-1] - 0.2])
>
>   In [71]: plot(x, y_sin)
>   Out[71]: [<matplotlib.lines.Line2D object at 0x96959ec>]
>
>   In [72]: fill_between(np.concatenate([x, x[::-1]]), err, facecolor='red',
> alpha=0.5)
>   Out[72]: <matplotlib.collections.PolyCollection object at 0x962758c>
>
> Admittedly the [::-1] thing is a bit counter-intuitive, but rather than
> adding a new plotting method, perhaps we would be better off with a helper
> method to create the xs and ys for fill_between
>
>   xs, ys = mlab.pad_line(x, y, 0.2)
>   fill_between(xs, ys)
>
> JDH

What about adding a property to the existing errorbar to let someone
change it to the filled version?  This could also, potentially, be
extended with other types of error bars if the need arises.

-Todd