Add to colour.lua

Added RGB-HSV, HSV-RGB, HSV-HSL, HSL-HSV conversion functions.
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zorg 2023-12-11 03:32:14 +01:00 committed by GitHub
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@ -173,7 +173,71 @@ function colour.rgb_to_hsl(r, g, b)
return h / 6, s, l
end
--todo: hsv
--convert hsv to rgb
--all components are 0-1, hue is fraction of a turn rather than degrees or radians
function colour.hsv_to_rgb(h, s, v)
--wedge slice
local w = (math.wrap(h, 0, 1) * 6)
--chroma
local c = v * s
--secondary
local x = c * (1 - math.abs(w % 2 - 1))
--match value
local m = v - c
--per-wedge logic
local r, g, b = m, m, m
if w < 1 then
r = r + c
g = g + x
elseif w < 2 then
r = r + x
g = g + c
elseif w < 3 then
g = g + c
b = b + x
elseif w < 4 then
g = g + x
b = b + c
elseif w < 5 then
b = b + c
r = r + x
else
b = b + x
r = r + c
end
return r, g, b
end
--convert rgb to hsv
function colour.rgb_to_hsv(r, g, b)
local max, min = math.max(r, g, b), math.min(r, g, b)
if max == min then return 0, 0, min end
local v, d = max, max - min
local s = (max == 0) and 0 or (d / max)
local h --depends on below
if max == r then
h = (g - b) / d
if g < b then h = h + 6 end
elseif max == g then
h = (b - r) / d + 2
else
h = (r - g) / d + 4
end
return h / 6, s, v
end
--conversion between hsl and hsv
function colour.hsl_to_hsv(h, s, l)
local v = l + s * math.min(l, 1 - l)
local s = (v == 0) and 0 or (2 * (1 - l / v))
return h, s, v
end
function colour.hsv_to_hsl(h, s, v)
local l = v * (1 - s / 2)
local s = (l == 0 or l == 1) and 0 or ((v - l) / math.min(l, 1 - l))
return h, s, l
end
--oklab https://bottosson.github.io/posts/oklab/
function colour.oklab_to_rgb(l, a, b)