def __init__(self, data = ( 'root', ( 'foo', ( 'leaf', ) ), ( 'bar', ( 'node', ( 'buz', ( 'yeah', ) ), ( 'boo', ( 'what', ) ), ( 'hoo', ( 'ever', ) ) ) ) ) ): self._data = data self._canvas = TextCanvas() self._draw()
class TextTree(object):
"""
Draws an ASCII art representation of a tree:
root
_______|_______
| |
foo bar
| |
| |
leaf node
_______|_______
| | |
buz boo hoo
| | |
| | |
yeah what ever
The above example was drawn from the following tuple structure:
(
'root',
(
'foo',
(
'leaf',
)
),
(
'bar',
(
'node',
(
'buz',
(
'yeah',
)
),
(
'boo',
(
'what',
)
),
(
'hoo',
(
'ever',
)
)
)
)
)
Example usage:
print str(TextTree())
"""
def __init__(self, data =
(
'root',
(
'foo',
(
'leaf',
)
),
(
'bar',
(
'node',
(
'buz',
(
'yeah',
)
),
(
'boo',
(
'what',
)
),
(
'hoo',
(
'ever',
)
)
)
)
)
):
self._data = data
self._canvas = TextCanvas()
self._draw()
def get_canvas(self):
"""Get the TextCanvas the tree was drawn on"""
return self._canvas
# From http://stackoverflow.com/questions/10482339/how-to-find-median
@classmethod
def median(cls, lst):
even = (0 if len(lst) % 2 else 1) + 1
half = (len(lst) - 1) / 2
return sum(sorted(lst)[half:half + even]) / float(even)
def _draw_title(self, title, padding = 2):
# Here's how the title should be positioned relative to the stem below it for some example title widths.
# t (0, 0)
# | (0, 0)
# ti (0, 0)
# | (0, 0)
# tit (-1, 0)
# | (0, 0)
# titl (-1, 0)
# | (0, 0)
# title (-2, 0)
# | (0, 0)
# Set the title corresponding to the sketches above
title = " "*padding + title + " "*padding
title_x_position = math.ceil((1.0-len(title))/2.0) # gradually goes more to the left
self._canvas.set(title, title_x_position, 0)
def _x_centers(self, canvases):
x_centers = []
# Start at the leftmost point in the first canvas
current_x = math.ceil((1.0-canvases[0].width())/2.0)
for i, canvas in enumerate(canvases):
# Go to the center position of the current canvas
current_x -= math.ceil((1.0-canvas.width())/2.0)
x_centers.append(current_x)
# Go to the leftmost position of the next canvas
current_x += math.ceil((1.0-canvas.width())/2.0) + canvas.width()
return x_centers
def _draw(self):
title, subtrees = self._data[0], self._data[1:]
self._draw_title(title)
# Stem and drawing of subtrees is only needed if there are some.
if not subtrees:
return
# Where to place those subtrees exactly isn't known until the width of subtree drawings is known.
# So draw them all and then move them into place.
canvases = []
for subtree in subtrees:
tree = TextTree(subtree)
canvases.append(tree.get_canvas())
# Now at this point we've drawn the title and the vertical bit of stem and know how big the subtrees
# are. Lay them out next to each other.
#
# title
# |
#
# 1111112222223333333
#
# This layout problem is a bit hairier than just centering the blocks, as we would prefer the box below
# to align with the stem | under the label.
#
# Consider these two cases:
#
# title
# |
# |
# 1123
#
# title
# |
# |
# 1233
#
# Despite the total width being the same, actually they are placed differently! Turns out the solution
# is to place them according to the median point of the box centers. That way the middle one will end up
# at 0 or if there is no middle, then the midpoint ends up at 0.
#
x_centers = self._x_centers(canvases)
adjustment = math.floor(-self.median(x_centers))
x_centers = [x + adjustment for x in x_centers]
# Draw each canvas in the computed center
for canvas, x_center in zip(canvases, x_centers):
canvas.blit_to(self._canvas, x_center, 3)
r = range(1 + int(math.ceil(x_centers[0])), int(math.ceil(x_centers[-1])))
for x in r:
self._canvas.set('_', x, 1)
# Finally connect stems to centers of each subtree.
#
# title
# _____|_____
# | | |
# 1111112222223333333
for x_center in x_centers:
self._canvas.set('|', x_center, 2)
self._canvas.set('|', 0, 1)
def __str__(self):
return str(self._canvas)
