Lua Scripting • colors.lua

Code:

------------------------------------------------------------------------------- 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.-----------------------------------------------------------------------------local M = {}local Color = {}local Color_mt = {__metatable = {}, __index = Color}local rgb_string_to_hsl -- defined below------------------------------------------------------------------------------- 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-----------------------------------------------------------------------------local 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)endM.new = new------------------------------------------------------------------------------- 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-----------------------------------------------------------------------------local 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)endM.hsl_to_rgb = hsl_to_rgb------------------------------------------------------------------------------- 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-----------------------------------------------------------------------------local 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, lendM.rgb_to_hsl = rgb_to_hsl-- already local, see at the bottomfunction 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)endM.rgb_string_to_hsl = rgb_string_to_hsl------------------------------------------------------------------------------- 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 r, g, b = hsl_to_rgb(self.H, self.S, self.L)   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 bufferend------------------------------------------------------------------------------- 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 resultsend------------------------------------------------------------------------------- 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)endfunction Color:tint(r)      return self:lighten_to(self.L + (1-self.L)*r)endfunction Color:shade(r)      return self:lighten_to(self.L - self.L*r)end