Re: [Matplotlib-users] plotting with marker 'o' but not filled

[Eric F. <ef...@ha...>]

Tony S Yu wrote:
> On Jul 12, 2008, at 1:50 PM, Alan wrote:
> 
>> Hi List,
>>
>> I use Fink for Mac OSX, tiger 10.4.11.
>>
>> So with MPL 0.90.1, this script works fine:
>>
>> from matplotlib.pylab import *
>> import matplotlib, numpy
>> print matplotlib.__version, numpy.__version__
>> att1 = {'color': 'black', 'markerfacecolor': 'red', 'markersize':
>> 80.0, 'markeredgewidth': 1.0, 'alpha': 1.0, 'marker': 's',
>> 'markeredgecolor': 'blue'}
>> att2 = {'color': 'black', 'markerfacecolor': None, 'markersize': 8.0,
>> 'markeredgewidth': 1.0, 'alpha': 1.0, 'marker': 'o',
>> 'markeredgecolor': 'blue'}
>> plot([0],[0], **att1)
>> plot([0],[0], **att2)
>> show()
>>
>> I got just a blue circle line (not filled) over a red square. However,
>> trying the same script with updated MPL 0.91.3, I got:
>>
>> [snip]
>>  File "/sw/lib/python2.5/site-packages/matplotlib/colors.py", line
>> 279, in to_rgb
>>    raise ValueError('to_rgb: Invalid rgb arg "%s"\n%s' % (str(arg),  
>> exc))
>> ValueError: to_rgb: Invalid rgb arg "None"
>> cannot convert argument to rgb sequence

The error message is somewhat misleading in this case because of the 
quotes; it is failing on the Python object None, not the string "None".

>>
>> Bottom line, version 0.91.3 simply doesn't like 'markerfacecolor':
>> None anymore.
> 
> Could you try setting 'markerfacecolor' to 'none' (Note that this is  
> the string, not the keyword). I'm on version 0.98.2, but I think this  
> worked when I was using 0.91.3. I'm not sure why this change was made,  
> though.

We have been trying to move to the following standard for kwargs:

None (the Python object) means "use the default", usually an rcParams 
setting.  (In the case of markerfacecolor, it is not an rcParams value, 
it is the 'color' value.)

'none' or 'None' means "no color".

There is indeed a bug in the present code: 'markerfacecolor': None is 
raising an error because it is supposed to be converted to the default, 
which is 'auto', but when it is input as a plot kwarg, it isn't.  I will 
have that fixed shortly in the two svn branches.

Eric

> 
> Best,
> -Tony
> 
>>
>> So, is it a bug, or there's another way of getting a simple circle  
>> not filled?
>>
>> Many thanks in advance,
>> Alan