Update Colour utils

onlylegs/utils/colour.py

@@ -0,0 +1,131 @@
+"""
+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

onlylegs/utils/contrast.py

@@ -1,25 +0,0 @@
-"""
-Calculate the contrast between two colors
-"""
-
-
-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
-    uicolors = [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 uicolors
-    ]
-    lightness = (0.2126 * cont[0]) + (0.7152 * cont[1]) + (0.0722 * cont[2])
-
-    return light if lightness > threshold else dark