colorzero

colorzero is a color manipulation library for Python (yes, another one) which aims to be reasonably simple to use and “pythonic” in nature.

It does not aim to be as comprehensive, powerful, or that matter as correct as, say, colormath. colorzero originally grew out of work on my picamera project, hence it’s intended to be sufficiently simple that school children can use it without having to explain color spaces and illuminants. However, it does aim to be useful to a wide range of skills, hence it does include basic facilities for CIE Lab representations, and Delta-E calculations should you need them.

The major difference between colorzero and other libraries (grapefruit, colormath, etc.) is that its Color class is a namedtuple descendent. This means it is immutable; you cannot directly change the attributes of a Color instance. The major advantage of this is that instances can be used as keys in dictionaries (for simple LUTs), or placed in sets.

Manipulation of Color instances is done by typical operations with other classes the result of which is a new Color instance. For example:

>>> from colorzero import *
>>> Color('red') + Color('blue')
<Color html='#ff00ff' rgb=(1, 0, 1)>
>>> Color('magenta') - Color('red')
<Color html='#0000ff' rgb=(0, 0, 1)>
>>> Color('red') - Red(0.5)
<Color html='#800000' rgb=(0.5, 0, 0)>
>>> Color('green') + Color('grey').red
<Color html='#808000' rgb=(0.501961, 0.501961, 0)>
>>> Color.from_hls(0.5, 0.5, 1.0)
<Color html='#00ffff' rgb=(0, 1, 1)>
>>> Color.from_hls(0.5, 0.5, 1.0) * Lightness(0.8)
<Color html='#00cccc' rgb=(0, 0.8, 0.8)>
>>> (Color.from_hls(0.5, 0.5, 1.0) * Lightness(0.8)).hls
HLS(h=0.5, l=0.4, s=1.0)

Another interesting facility is the custom format strings that Color instances support, making them convenient for direct use in HTML or CSS templating:

>>> red = Color('red')
>>> black = Color('black')
>>> stylesheet = f"""\
.warning {{ color: {red:css}; }}
.table {{ border: 1px solid {black:html}; }}
"""
>>> print(stylesheet)
.warning { color: rgb(255, 0, 0); }
.table { border: 1px solid #000000; }

Or for in colorful terminal output:

>>> print(f'This is a {red:8}warning!{Default}')
This is a warning!
>>> f'This is a {red:8}warning!{Default}'
'This is a \x1b[1;31mwarning!\x1b[0m'

(on supported terminals, the first line of output above will print “warning!” in red)

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