This sounds like a job for properties! make
> _transform a property, and code that gets and sets it
> directly should still work. though People that were
> accessing an underscored name directly should expect
> this kind of problem.
The matplotlib artist kwarg properties act like python properties or
enthought traits, with some advantages and disadvantages over each
(mostly disadvantages, alas). We've discussed migrating to one or
another over the years, but haven't bitten the bullet. At each point
it's easier to extend the exiting implementation than refactor the
whole bit; the tyranny of small decisions.
Here are some of the pros and cons as I see them of enthought traits
vs python properties
Pros:
* compatibility with the rest of the enthought tool suite
* built in observer pattern
* automatic UI for wx users
* performance is better than python properties last time I looked
* matplotlib ships with enthought traits built in
Cons:
* smaller user base than python properties may imply
fewer 3rd party enhancements, less support, etc
* we have to maintain our copy of enthought traits to keep it
current and building or require an additional dependency
I spent some time working on matplotlib rc properties as enthought
traits as a precursor to porting matplotlib properties to traits.
Here is some example code showing how to define some representative rc
properties and construct a matplotlib artist using traits. Because
matplotlib ships with enthought traits already, you can run this
script with just matplotlib. Unfortunately, we do not ship the ex UI
component so you can't test that part. I'm a bit of a traits newbie
so there are probably better ways to do what I have done below.
import sys, os, re
import matplotlib.enthought.traits as traits
from matplotlib.cbook import is_string_like
from matplotlib.artist import Artist
doprint = True
flexible_true_trait = traits.Trait(
True,
{ 'true': True, 't': True, 'yes': True, 'y': True, 'on': True, True: True,
'false': False, 'f': False, 'no': False, 'n': False, 'off': False, False: False
} )
flexible_false_trait = traits.Trait( False, flexible_true_trait )
colors = {
'c' : '#00bfbf',
'b' : '#0000ff',
'g' : '#008000',
'k' : '#000000',
'm' : '#bf00bf',
'r' : '#ff0000',
'w' : '#ffffff',
'y' : '#bfbf00',
'gold' : '#FFD700',
'peachpuff' : '#FFDAB9',
'navajowhite' : '#FFDEAD',
}
def hex2color(s):
"Convert hex string (like html uses, eg, #efefef) to a r,g,b tuple"
return tuple([int(n, 16)/255.0 for n in (s[1:3], s[3:5], s[5:7])])
class RGBA(traits.HasTraits):
# r,g,b,a in the range 0-1 with default color 0,0,0,1 (black)
r = traits.Range(0., 1., 0.)
g = traits.Range(0., 1., 0.)
b = traits.Range(0., 1., 0.)
a = traits.Range(0., 1., 1.)
def __init__(self, r=0., g=0., b=0., a=1.):
self.r = r
self.g = g
self.b = b
self.a = a
def __repr__(self):
return 'r,g,b,a = (%1.2f, %1.2f, %1.2f, %1.2f)'%\
(self.r, self.g, self.b, self.a)
def tuple_to_rgba(ob, name, val):
tup = [float(x) for x in val]
if len(tup)==3:
r,g,b = tup
return RGBA(r,g,b)
elif len(tup)==4:
r,g,b,a = tup
return RGBA(r,g,b,a)
else:
raise ValueError
tuple_to_rgba.info = 'a RGB or RGBA tuple of floats'
def hex_to_rgba(ob, name, val):
rgx = re.compile('^#[0-9A-Fa-f]{6}$')
if not is_string_like(val):
raise TypeError
if rgx.match(val) is None:
raise ValueError
r,g,b = hex2color(val)
return RGBA(r,g,b,1.0)
hex_to_rgba.info = 'a hex color string'
def colorname_to_rgba(ob, name, val):
hex = colors[val.lower()]
r,g,b = hex2color(hex)
return RGBA(r,g,b,1.0)
colorname_to_rgba.info = 'a named color'
def float_to_rgba(ob, name, val):
val = float(val)
return RGBA(val, val, val, 1.)
float_to_rgba.info = 'a grayscale intensity'
Color = traits.Trait(RGBA(), float_to_rgba, colorname_to_rgba, RGBA,
hex_to_rgba, tuple_to_rgba)
def file_exists(ob, name, val):
fh = file(val, 'r')
return val
def path_exists(ob, name, val):
os.path.exists(val)
linestyles = ('-', '--', '-.', ':', 'steps', 'None')
TICKLEFT, TICKRIGHT, TICKUP, TICKDOWN = range(4)
linemarkers = (None, '.', ',', 'o', '^', 'v', '<', '>', 's',
'+', 'x', 'd', 'D', '|', '_', 'h', 'H',
'p', '1', '2', '3', '4',
TICKLEFT,
TICKRIGHT,
TICKUP,
TICKDOWN,
'None'
)
class LineRC(traits.HasTraits):
linewidth = traits.Float(0.5)
linestyle = traits.Trait(*linestyles)
color = Color
marker = traits.Trait(*linemarkers)
markerfacecolor = Color
markeredgecolor = Color
markeredgewidth = traits.Float(0.5)
markersize = traits.Float(6)
antialiased = flexible_true_trait
data_clipping = flexible_false_trait
class PatchRC(traits.HasTraits):
linewidth = traits.Float(1.0)
facecolor = Color
edgecolor = Color
antialiased = flexible_true_trait
timezones = 'UTC', 'US/Central', 'ES/Eastern' # fixme: and many more
backends = ('GTKAgg', 'Cairo', 'FltkAgg', 'GD', 'GDK', 'GTK', 'Agg',
'GTKCairo', 'Paint', 'PS', 'SVG', 'Template', 'TkAgg',
'WX')
class RC(traits.HasTraits):
backend = traits.Trait(*backends)
numerix = traits.Trait('Numeric', 'numarray')
interactive = flexible_false_trait
toolbar = traits.Trait('toolbar2', 'classic', None)
timezone = traits.Trait(*timezones)
lines = traits.Trait(LineRC())
patch = traits.Trait(PatchRC())
rc = RC()
rc.lines.color = 'r'
if doprint:
print 'RC'
rc.print_traits()
print 'RC lines'
rc.lines.print_traits()
print 'RC patches'
rc.patch.print_traits()
class Patch(Artist, traits.HasTraits):
linewidth = traits.Float(0.5)
facecolor = Color
fc = facecolor
edgecolor = Color
fill = flexible_true_trait
def __init__(self,
edgecolor=None,
facecolor=None,
linewidth=None,
antialiased = None,
fill=1,
**kwargs
):
Artist.__init__(self)
if edgecolor is None: edgecolor = rc.patch.edgecolor
if facecolor is None: facecolor = rc.patch.facecolor
if linewidth is None: linewidth = rc.patch.linewidth
if antialiased is None: antialiased = rc.patch.antialiased
self.edgecolor = edgecolor
self.facecolor = facecolor
self.linewidth = linewidth
self.antialiased = antialiased
self.fill = fill
p = Patch()
p.facecolor = '#bfbf00'
p.edgecolor = 'gold'
p.facecolor = (1,.5,.5,.25)
p.facecolor = 0.25
p.fill = 'f'
print 'p.facecolor', type(p.facecolor), p.facecolor
print 'p.fill', type(p.fill), p.fill
if p.fill_: print 'fill'
else: print 'no fill'
if doprint:
print
print 'Patch'
p.print_traits()
JDH