  Travis-CI: # pylab_examples example code: colours.py¶

```# -*- noplot -*-
"""
Some simple functions to generate colours.
"""
import numpy as np
from matplotlib import colors as mcolors

def pastel(colour, weight=2.4):
""" Convert colour into a nice pastel shade"""
rgb = np.asarray(mcolors.to_rgba(colour)[:3])
# scale colour
maxc = max(rgb)
if maxc < 1.0 and maxc > 0:
# scale colour
scale = 1.0 / maxc
rgb = rgb * scale
# now decrease saturation
total = rgb.sum()
slack = 0
for x in rgb:
slack += 1.0 - x

# want to increase weight from total to weight
# pick x s.t.  slack * x == weight - total
# x = (weight - total) / slack
x = (weight - total) / slack

rgb = [c + (x * (1.0 - c)) for c in rgb]

return rgb

def get_colours(n):
""" Return n pastel colours. """
base = np.asarray([[1, 0, 0], [0, 1, 0], [0, 0, 1]])

if n <= 3:
return base[0:n]

# how many new colours to we need to insert between
# red and green and between green and blue?
needed = (((n - 3) + 1) / 2, (n - 3) / 2)

colours = []
for start in (0, 1):
for x in np.linspace(0, 1, needed[start] + 2):
colours.append((base[start] * (1.0 - x)) +
(base[start + 1] * x))

return [pastel(c) for c in colours[0:n]]
```

Keywords: python, matplotlib, pylab, example, codex (see Search examples)