# -*- coding: utf-8 -*-
"""Color calculations.
"""
import colorsys
# noinspection PyAugmentAssignment
# import hashlib
START_COLOR = 0 # Value can be changed from command-line argument
[docs]
def frange(start, end, step):
"""Like range(), but with floats.
"""
val = start
while val < end:
yield val
val += step
[docs]
def distinct_hues(count):
"""Return ``count`` hues, equidistantly spaced.
"""
for i in frange(0., 360., 360. / count):
hue = ((i + START_COLOR) % 360) / 360.
yield hue
[docs]
class ColorSpace(object):
def __init__(self, nodes):
self.nodes = {}
for node in nodes:
parts = node.name.split('.')
self.add_to_tree(parts, self.nodes)
self.basecolors = distinct_hues(len(self.nodes))
self.colors = dict(zip(sorted(self.nodes.keys()), self.basecolors))
[docs]
def add_to_tree(self, parts, tree):
if not parts:
return
first, rest = parts[0], parts[1:]
if first not in tree:
tree[first] = {}
self.add_to_tree(rest, tree[first])
[docs]
def color(self, src):
nodename = src.name
parts = nodename.split('.')
hue = self.colors[parts[0]]
saturation = min(0.95, 0.4 + 0.1 * (src.out_degree - 1))
lightness = max(0.3, 0.5 - 0.02 * (src.in_degree - 1))
bg = rgb2eightbit(colorsys.hls_to_rgb(hue, lightness, saturation))
black = (0, 0, 0)
white = (255, 255, 255)
fg = foreground(bg, black, white)
return bg, fg
def __str__(self): # pragma: nocover
import pprint
return pprint.pformat(self.colors)
[docs]
def rgb2eightbit(rgb):
"""Convert floats in [0..1] to integers in [0..256)
"""
return tuple(int(x * 256) for x in rgb)
[docs]
def name2rgb(hue):
"""Originally used to calculate color based on module name.
"""
r, g, b = colorsys.hsv_to_rgb(hue / 360.0, .8, .7)
return tuple(int(x * 256) for x in [r, g, b])
[docs]
def brightness(r, g, b):
"""From w3c (range 0..255).
"""
return (r * 299 + g * 587 + b * 114) / 1000
[docs]
def brightnessdiff(a, b):
"""greater than 125 is good.
"""
return abs(brightness(*a) - brightness(*b))
[docs]
def colordiff(rgb1, rgb2):
"""From w3c (greater than 500 is good).
(range [0..765])
"""
(r, g, b) = rgb1
(r2, g2, b2) = rgb2
return (
max(r, r2) - min(r, r2) +
max(g, g2) - min(g, g2) +
max(b, b2) - min(b, b2)
)
[docs]
def foreground(background, *options):
"""Find the best foreground color from `options` based on `background`
color.
"""
def absdiff(a, b):
return brightnessdiff(a, b)
# return 3 * brightnessdiff(a, b) + colordiff(a, b)
diffs = [(absdiff(background, color), color) for color in options]
diffs.sort(reverse=True)
return diffs[0][1]
[docs]
def rgb2css(rgb):
"""Convert rgb to hex.
"""
return '#%02x%02x%02x' % rgb