Hammerspoon Color Picker Script

HammerspoonColorPicker.lua

local modifier = {"alt"}

function rgbToHex(red, green, blue)
    return "#" .. string.format("%x", red) .. string.format("%x", green) ..
               string.format("%x", blue)
end

function hslToRgb(h, s, l)
    if s == 0 then return l, l, l end
    local function to(p, q, t)
        if t < 0 then t = t + 1 end
        if t > 1 then t = t - 1 end
        if t < .16667 then return p + (q - p) * 6 * t end
        if t < .5 then return q end
        if t < .66667 then return p + (q - p) * (.66667 - t) * 6 end
        return p
    end
    local q = l < .5 and l * (1 + s) or l + s - l * s
    local p = 2 * l - q
    return to(p, q, h + .33334), to(p, q, h), to(p, q, h - .33334)
end

function round(number)
    if (number > 0.5) then
        return math.min(255, math.ceil(number * 255.9999))
    else
        return math.min(255, math.floor(number * 255.9999))
    end
end

function pickColor()
    local absolute = hs.mouse.getAbsolutePosition()

    local rectToShot = hs.geometry.rect(absolute.x, absolute.y, 10, 10)
    local screen = hs.mouse.getCurrentScreen()
    local snapshot = screen:snapshot(rectToShot)
    local color = snapshot:colorAt(hs.geometry.point(0, 0))

    -- -- Convert RGB to Hex
    local red = round(color.red)
    local green = round(color.green)
    local blue = round(color.blue)
    -- Hex Value is not on Point, maybe use HSB?
    local hex = rgbToHex(red, green, blue)

    -- Show to user and copy to clipboard
    hs.alert.show(hex)
    hs.alert.show(red .. "," .. green .. "," .. blue)
    hs.pasteboard.writeDataForUTI(nil, "public.utf8-plain-text", hex)
end

local leftClickTap = hs.eventtap.new({hs.eventtap.event.types.leftMouseDown},
                                     pickColor)

hs.hotkey.bind(modifier, "a", function() leftClickTap:start() end,
               function() leftClickTap:stop() end)