python-gallery/onlylegs/utils/colour.py
2023-05-29 10:39:53 +00:00

132 lines
2.8 KiB
Python

"""
Colour tools used by OnlyLegs
Source 1: https://gist.github.com/mathebox/e0805f72e7db3269ec22
"""
import math
def contrast(background, light, dark, threshold=0.179):
"""
background: tuple of (r, g, b) values
light: color to use if the background is light
dark: color to use if the background is dark
threshold: the threshold to use for determining lightness, the default is w3 recommended
"""
red = background[0]
green = background[1]
blue = background[2]
# Calculate contrast
colors = [red / 255, green / 255, blue / 255]
cont = [
col / 12.92 if col <= 0.03928 else ((col + 0.055) / 1.055) ** 2.4
for col in colors
]
lightness = (0.2126 * cont[0]) + (0.7152 * cont[1]) + (0.0722 * cont[2])
return light if lightness > threshold else dark
def rgb_to_hsv(r, g, b):
r = float(r)
g = float(g)
b = float(b)
high = max(r, g, b)
low = min(r, g, b)
h, s, v = high, high, high
d = high - low
s = 0 if high == 0 else d/high
if high == low:
h = 0.0
else:
h = {
r: (g - b) / d + (6 if g < b else 0),
g: (b - r) / d + 2,
b: (r - g) / d + 4,
}[high]
h /= 6
return h, s, v
def hsv_to_rgb(h, s, v):
i = math.floor(h*6)
f = h*6 - i
p = v * (1-s)
q = v * (1-f*s)
t = v * (1-(1-f)*s)
r, g, b = [
(v, t, p),
(q, v, p),
(p, v, t),
(p, q, v),
(t, p, v),
(v, p, q),
][int(i % 6)]
return r, g, b
def rgb_to_hsl(r, g, b):
r = float(r)
g = float(g)
b = float(b)
high = max(r, g, b)
low = min(r, g, b)
h, s, v = ((high + low) / 2,)*3
if high == low:
h = 0.0
s = 0.0
else:
d = high - low
s = d / (2 - high - low) if l > 0.5 else d / (high + low)
h = {
r: (g - b) / d + (6 if g < b else 0),
g: (b - r) / d + 2,
b: (r - g) / d + 4,
}[high]
h /= 6
return h, s, v
def hsl_to_rgb(h, s, l):
def hue_to_rgb(p, q, t):
t += 1 if t < 0 else 0
t -= 1 if t > 1 else 0
if t < 1/6:
return p + (q - p) * 6 * t
if t < 1/2:
return q
if t < 2/3:
p + (q - p) * (2/3 - t) * 6
return p
if s == 0:
r, g, b = l, l, l
else:
q = l * (1 + s) if l < 0.5 else l + s - l * s
p = 2 * l - q
r = hue_to_rgb(p, q, h + 1/3)
g = hue_to_rgb(p, q, h)
b = hue_to_rgb(p, q, h - 1/3)
return r, g, b
def hsv_to_hsl(h, s, v):
l = 0.5 * v * (2 - s)
s = v * s / (1 - math.fabs(2*l-1))
return h, s, l
def hsl_to_hsv(h, s, l):
v = (2*l + s*(1-math.fabs(2*l-1)))/2
s = 2*(v-l)/v
return h, s, v