270 lines
9.2 KiB
Lua
270 lines
9.2 KiB
Lua
-----------------------------------------------------------------------------
|
|
-- Provides support for color manipulation in HSL color space.
|
|
--
|
|
-- http://sputnik.freewisdom.org/lib/colors/
|
|
--
|
|
-- License: MIT/X
|
|
--
|
|
-- (c) 2008 Yuri Takhteyev (yuri@freewisdom.org) *
|
|
--
|
|
-- * rgb_to_hsl() implementation was contributed by Markus Fleck-Graffe.
|
|
-----------------------------------------------------------------------------
|
|
|
|
module(..., package.seeall)
|
|
|
|
local Color = {}
|
|
local Color_mt = {__metatable = {}, __index = Color}
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Instantiates a new "color".
|
|
--
|
|
-- @param H hue (0-360) _or_ an RGB string ("#930219")
|
|
-- @param S saturation (0.0-1.0)
|
|
-- @param L lightness (0.0-1.0)
|
|
-- @return an instance of Color
|
|
-----------------------------------------------------------------------------
|
|
function new(H, S, L)
|
|
if type(H) == "string" and H:sub(1,1)=="#" and H:len() == 7 then
|
|
H, S, L = rgb_string_to_hsl(H)
|
|
end
|
|
assert(Color_mt)
|
|
return setmetatable({H = H, S = S, L = L}, Color_mt)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Converts an HSL triplet to RGB
|
|
-- (see http://homepages.cwi.nl/~steven/css/hsl.html).
|
|
--
|
|
-- @param h hue (0-360)
|
|
-- @param s saturation (0.0-1.0)
|
|
-- @param L lightness (0.0-1.0)
|
|
-- @return an R, G, and B component of RGB
|
|
-----------------------------------------------------------------------------
|
|
|
|
function hsl_to_rgb(h, s, L)
|
|
h = h/360
|
|
local m1, m2
|
|
if L<=0.5 then
|
|
m2 = L*(s+1)
|
|
else
|
|
m2 = L+s-L*s
|
|
end
|
|
m1 = L*2-m2
|
|
|
|
local function _h2rgb(m1, m2, h)
|
|
if h<0 then h = h+1 end
|
|
if h>1 then h = h-1 end
|
|
if h*6<1 then
|
|
return m1+(m2-m1)*h*6
|
|
elseif h*2<1 then
|
|
return m2
|
|
elseif h*3<2 then
|
|
return m1+(m2-m1)*(2/3-h)*6
|
|
else
|
|
return m1
|
|
end
|
|
end
|
|
|
|
return _h2rgb(m1, m2, h+1/3), _h2rgb(m1, m2, h), _h2rgb(m1, m2, h-1/3)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Converts an RGB triplet to HSL.
|
|
-- (see http://easyrgb.com)
|
|
--
|
|
-- @param r red (0.0-1.0)
|
|
-- @param g green (0.0-1.0)
|
|
-- @param b blue (0.0-1.0)
|
|
-- @return corresponding H, S and L components
|
|
-----------------------------------------------------------------------------
|
|
|
|
function rgb_to_hsl(r, g, b)
|
|
--r, g, b = r/255, g/255, b/255
|
|
local min = math.min(r, g, b)
|
|
local max = math.max(r, g, b)
|
|
local delta = max - min
|
|
|
|
local h, s, l = 0, 0, ((min+max)/2)
|
|
|
|
if l > 0 and l < 0.5 then s = delta/(max+min) end
|
|
if l >= 0.5 and l < 1 then s = delta/(2-max-min) end
|
|
|
|
if delta > 0 then
|
|
if max == r and max ~= g then h = h + (g-b)/delta end
|
|
if max == g and max ~= b then h = h + 2 + (b-r)/delta end
|
|
if max == b and max ~= r then h = h + 4 + (r-g)/delta end
|
|
h = h / 6;
|
|
end
|
|
|
|
if h < 0 then h = h + 1 end
|
|
if h > 1 then h = h - 1 end
|
|
|
|
return h * 360, s, l
|
|
end
|
|
|
|
function rgb_string_to_hsl(rgb)
|
|
return rgb_to_hsl(tonumber(rgb:sub(2,3), 16)/255,
|
|
tonumber(rgb:sub(4,5), 16)/255,
|
|
tonumber(rgb:sub(6,7), 16)/255)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Converts the color to an RGB string.
|
|
--
|
|
-- @return a 6-digit RGB representation of the color prefixed
|
|
-- with "#" (suitable for inclusion in HTML)
|
|
-----------------------------------------------------------------------------
|
|
|
|
function Color:to_rgb()
|
|
local rgb = {hsl_to_rgb(self.H, self.S, self.L)}
|
|
local buffer = "#"
|
|
for i,v in ipairs(rgb) do
|
|
buffer = buffer..string.format("%02x",math.floor(v*255+0.5))
|
|
end
|
|
return buffer
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates a new color with hue different by delta.
|
|
--
|
|
-- @param delta a delta for hue.
|
|
-- @return a new instance of Color.
|
|
-----------------------------------------------------------------------------
|
|
function Color:hue_offset(delta)
|
|
return new((self.H + delta) % 360, self.S, self.L)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates a complementary color.
|
|
--
|
|
-- @return a new instance of Color
|
|
-----------------------------------------------------------------------------
|
|
function Color:complementary()
|
|
return self:hue_offset(180)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates two neighboring colors (by hue), offset by "angle".
|
|
--
|
|
-- @param angle the difference in hue between this color and the
|
|
-- neighbors
|
|
-- @return two new instances of Color
|
|
-----------------------------------------------------------------------------
|
|
function Color:neighbors(angle)
|
|
local angle = angle or 30
|
|
return self:hue_offset(angle), self:hue_offset(360-angle)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates two new colors to make a triadic color scheme.
|
|
--
|
|
-- @return two new instances of Color
|
|
-----------------------------------------------------------------------------
|
|
function Color:triadic()
|
|
return self:neighbors(120)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates two new colors, offset by angle from this colors complementary.
|
|
--
|
|
-- @param angle the difference in hue between the complementary and
|
|
-- the returned colors
|
|
-- @return two new instances of Color
|
|
-----------------------------------------------------------------------------
|
|
function Color:split_complementary(angle)
|
|
return self:neighbors(180-(angle or 30))
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates a new color with saturation set to a new value.
|
|
--
|
|
-- @param saturation the new saturation value (0.0 - 1.0)
|
|
-- @return a new instance of Color
|
|
-----------------------------------------------------------------------------
|
|
function Color:desaturate_to(saturation)
|
|
return new(self.H, saturation, self.L)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates a new color with saturation set to a old saturation times r.
|
|
--
|
|
-- @param r the multiplier for the new saturation
|
|
-- @return a new instance of Color
|
|
-----------------------------------------------------------------------------
|
|
function Color:desaturate_by(r)
|
|
return new(self.H, self.S*r, self.L)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates a new color with lightness set to a new value.
|
|
--
|
|
-- @param lightness the new lightness value (0.0 - 1.0)
|
|
-- @return a new instance of Color
|
|
-----------------------------------------------------------------------------
|
|
function Color:lighten_to(lightness)
|
|
return new(self.H, self.S, lightness)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates a new color with lightness set to a old lightness times r.
|
|
--
|
|
-- @param r the multiplier for the new lightness
|
|
-- @return a new instance of Color
|
|
-----------------------------------------------------------------------------
|
|
function Color:lighten_by(r)
|
|
return new(self.H, self.S, self.L*r)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates n variations of this color using supplied function and returns
|
|
-- them as a table.
|
|
--
|
|
-- @param f the function to create variations
|
|
-- @param n the number of variations
|
|
-- @return a table with n values containing the new colors
|
|
-----------------------------------------------------------------------------
|
|
function Color:variations(f, n)
|
|
n = n or 5
|
|
local results = {}
|
|
for i=1,n do
|
|
table.insert(results, f(self, i, n))
|
|
end
|
|
return results
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates n tints of this color and returns them as a table
|
|
--
|
|
-- @param n the number of tints
|
|
-- @return a table with n values containing the new colors
|
|
-----------------------------------------------------------------------------
|
|
function Color:tints(n)
|
|
local f = function (color, i, n)
|
|
return color:lighten_to(color.L + (1-color.L)/n*i)
|
|
end
|
|
return self:variations(f, n)
|
|
end
|
|
|
|
-----------------------------------------------------------------------------
|
|
-- Creates n shades of this color and returns them as a table
|
|
--
|
|
-- @param n the number of shades
|
|
-- @return a table with n values containing the new colors
|
|
-----------------------------------------------------------------------------
|
|
function Color:shades(n)
|
|
local f = function (color, i, n)
|
|
return color:lighten_to(color.L - (color.L)/n*i)
|
|
end
|
|
return self:variations(f, n)
|
|
end
|
|
|
|
function Color:tint(r)
|
|
return self:lighten_to(self.L + (1-self.L)*r)
|
|
end
|
|
|
|
function Color:shade(r)
|
|
return self:lighten_to(self.L - self.L*r)
|
|
end
|
|
|
|
Color_mt.__tostring = Color.to_rgb
|