如何子类化Pygal图

Question

I'm looking at subclassing the XY graph in Pygal, as I want to try override some of the Graph's methods such as _x_axis and _y_axis .

import pygal
from pygal.style import Style, CleanStyle

class CustomXY(pygal.XY):
    def __init__(self, *args, **kwargs):
        super(CustomXY, self).__init__(*args, **kwargs)
    def  _x_axis(self):
        pass
    def  _y_axis(self):
        pass

scatter = CustomXY(stroke=False, show_y_guides=False, truncate_legend=20)

When I try to run this code I get this error:

Traceback (most recent call last):
  File "pygal_test2.py", line 12, in <module>
    scatter = CustomXY(stroke=False, show_y_guides=False, truncate_legend=20)
  File "pygal_test2.py", line 6, in __init__
    super(CustomXY, self).__init__(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/pygal/ghost.py", line 71, in __init__
    self.cls = REAL_CHARTS[name]
KeyError: 'CustomXY'

Replacing CustomXY(pygal.XY) with CustomXY(pygal.graph.xy.XY) gives me this error:

Traceback (most recent call last):
  File "pygal_test2.py", line 12, in <module>
    scatter = CustomXY(stroke=False, show_y_guides=False, truncate_legend=20)
  File "pygal_test2.py", line 6, in __init__
    super(CustomXY, self).__init__(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/pygal/graph/line.py", line 33, in __init__
    super(Line, self).__init__(*args, **kwargs)
TypeError: __init__() got an unexpected keyword argument 'stroke'

What is the preferred way to subclass Pygal graphs?

Answer 1

It is an open source project, is there a particular reason you don't want to make the changes in your own fork version of XY?

http://pygal.org/

We all see the see that banner in the top right... right?

In all seriousness I am a little thrown off by the class Ghost throwing this error in its init considering that Ghost isn't in the object Hierarchy for your new class.

pygal looks like a cool package and I'm interested in what others people have to say here.