Re: [matplotlib-devel] Loss of filled vs. stroked distinction by Collections

Thanks for the fix - works for me on this afternoon's SVN.

-Eric

On Mon, Dec 15, 2008 at 1:27 AM, Eric Firing <ef...@ha...> wrote:
> Eric Bruning wrote:
>>
>> I think of artists as having visual properties that persist (e.g.,
>> filled vs. outlined, a colormap with min and max values) even as data
>> associated with the artist is changed. In the edge case described
>> below, this doesn't seem to hold true.
>>
>> I have code that animates a scatter plot by sub-selecting the data
>> stored in a collection artist. In cases where some frames contain no
>> data, the scatter artist's data is temporarily empty. On subsequent
>> frames (once there is data again) some of the visual properties my
>> filled point becomes an outlined point, as in the code below.
>>
>> # Filled single point with no outline
>> sc = scatter([1],[1],c=[1], edgecolors='none')
>>
>> # Cache the data
>> xy=sc.get_offsets()
>> s=sc.get_array()
>>
>> sel=s<0
>> sc.set_offsets(xy[sel,:])
>> sc.set_array(s[sel])
>>
>> # No data, so nothing shown. No problem.
>> sc.figure.canvas.draw()
>>
>> # Now restore the original data
>> sc.set_offsets(xy)
>> sc.set_array(s)
>>
>> # Outlined single point with no fill
>> sc.figure.canvas.draw()
>> sc.get_edgecolors()
>> sc.get_facecolors()
>> sc.get_array()
>>
>> The fix probably has to do with Collection.update_scalarmappable.
>> When set_array([ ]) happens,
>>        len(self._facecolors) > 0, therefore
>>        self._facecolors = to_rgba([  ]),
>> When set_array([1]) restores data,
>>        len(self._facecolors) == 0, therefore
>>        self._edgecolors = self.to_rgba([1])
>>
>> Should is_filled vs. is_stroked be preserved in this case? If so, is
>> there a more elegant fix than to add is_filled and is_stroked
>> properties that are checked by update_scalarmappable?
>
> I don't see a better way, so I implemented your suggestion.
>
> Eric
>