Use multiple color spaces simultaneously

For example, use RGB, HSL, and CMYK.

local ColorInput = require("ccc.input")
local convert = require("ccc.utils.convert")

local RgbHslCmykInput = setmetatable({
    name = "RGB/HSL/CMYK",
    max = { 1, 1, 1, 360, 1, 1, 1, 1, 1, 1 },
    min = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    delta = { 1 / 255, 1 / 255, 1 / 255, 1, 0.01, 0.01, 0.005, 0.005, 0.005, 0.005 },
    bar_name = { "R", "G", "B", "H", "S", "L", "C", "M", "Y", "K" },
}, { __index = ColorInput })

function RgbHslCmykInput.format(n, i)
    if i <= 3 then
        -- RGB
        n = n * 255
    elseif i == 5 or i == 6 then
        -- S or L of HSL
        n = n * 100
    elseif i >= 7 then
        -- CMYK
        return ("%5.1f%%"):format(math.floor(n * 200) / 2)
    end
    return ("%6d"):format(n)
end

function RgbHslCmykInput.from_rgb(RGB)
    local HSL = convert.rgb2hsl(RGB)
    local CMYK = convert.rgb2cmyk(RGB)
    local R, G, B = unpack(RGB)
    local H, S, L = unpack(HSL)
    local C, M, Y, K = unpack(CMYK)
    return { R, G, B, H, S, L, C, M, Y, K }
end

function RgbHslCmykInput.to_rgb(value)
    return { value[1], value[2], value[3] }
end

function RgbHslCmykInput:_set_rgb(RGB)
    self.value[1] = RGB[1]
    self.value[2] = RGB[2]
    self.value[3] = RGB[3]
end

function RgbHslCmykInput:_set_hsl(HSL)
    self.value[4] = HSL[1]
    self.value[5] = HSL[2]
    self.value[6] = HSL[3]
end

function RgbHslCmykInput:_set_cmyk(CMYK)
    self.value[7] = CMYK[1]
    self.value[8] = CMYK[2]
    self.value[9] = CMYK[3]
    self.value[10] = CMYK[4]
end

function RgbHslCmykInput:callback(index, new_value)
    self.value[index] = new_value
    local v = self.value
    if index <= 3 then
        local RGB = { v[1], v[2], v[3] }
        local HSL = convert.rgb2hsl(RGB)
        local CMYK = convert.rgb2cmyk(RGB)
        self:_set_hsl(HSL)
        self:_set_cmyk(CMYK)
    elseif index <= 6 then
        local HSL = { v[4], v[5], v[6] }
        local RGB = convert.hsl2rgb(HSL)
        local CMYK = convert.rgb2cmyk(RGB)
        self:_set_rgb(RGB)
        self:_set_cmyk(CMYK)
    else
        local CMYK = { v[7], v[8], v[9], v[10] }
        local RGB = convert.cmyk2rgb(CMYK)
        local HSL = convert.rgb2hsl(RGB)
        self:_set_rgb(RGB)
        self:_set_hsl(HSL)
    end
end

local ccc = require("ccc")
ccc.setup({
    inputs = {
        RgbHslCmykInput,
    },
})