Initial commit

lua/kanso/lib/color.lua

@@ -0,0 +1,84 @@
+local hsluv = require("kanso.lib.hsluv")
+
+---@class HSLuvColor
+local Color = {}
+local Color_mt = {
+    __index = Color,
+    __tostring = function(self)
+        return self:to_hex()
+    end,
+}
+
+local function none_to_hex()
+    return "NONE"
+end
+
+---Create a new HSLuv color object from a RGB hex string
+---@param hex string Hex color
+---@return HSLuvColor
+function Color.new(hex)
+    if hex:lower() == "none" then
+        return setmetatable({ H = 0, S = 0, L = 0, to_hex = none_to_hex }, Color_mt)
+    end
+    local H, S, L = unpack(hsluv.hex_to_hsluv(hex))
+    return setmetatable({ H = H, S = S, L = L }, Color_mt)
+end
+
+function Color:to_rgb()
+    return hsluv.hsluv_to_rgb({ self.H, self.S, self.L })
+end
+
+function Color:to_hex()
+    return hsluv.hsluv_to_hex({ self.H, self.S, self.L })
+end
+
+local function blendRGB(a, b, r)
+    local c = {}
+    for i = 1, 3 do
+        c[i] = math.sqrt((1 - r) * math.pow(a[i], 2) + r * math.pow(b[i], 2))
+    end
+    return c
+end
+
+--- Blend Color with another color (hex)
+---@param b string Hex color
+---@param r number Blend ratio [0, 1]
+---@return HSLuvColor
+function Color:blend(b, r)
+    if b:lower() == "none" then
+        return self
+    end
+    local c = blendRGB(self:to_rgb(), hsluv.hex_to_rgb(b), r)
+    self.H, self.S, self.L = unpack(hsluv.rgb_to_hsluv(c))
+    return self
+end
+
+---@param r number Brighten ratio [-1, 1]
+---@param bg? string background color, if light, r = -r
+---@return HSLuvColor
+function Color:brighten(r, bg)
+    if bg and bg:lower() == "none" then
+        return self
+    end
+    local bg_lightness = bg and hsluv.hex_to_hsluv(bg)[3] or 0
+    r = bg_lightness > 50 and -r or r
+
+    local lspace = r > 0 and 100 - self.L or self.L
+    self.L = self.L + lspace * r
+    return self
+end
+
+---@param r number Saturate ratio [-1, 1]
+---@return HSLuvColor
+function Color:saturate(r)
+    local lspace = r > 0 and 100 - self.S or self.S
+    self.S = self.S + lspace * r
+    return self
+end
+
+local M = {}
+return setmetatable(M, {
+    __call = function(_, ...)
+        return Color.new(...)
+    end,
+})