-- -- This module implements  --  {{Color contrast ratio}} --  {{Greater color contrast ratio}} --  {{ColorToLum}} --  {{RGBColorToLum}} -- local p = {} local HTMLcolor = mw.loadData( 'Module:Color contrast/colors' )  local function sRGB ( v )  	if (v <= 0.03928) then  		v = v / 12.92 	else 		v = math.pow((v+0.055)/1.055, 2.4) 	end 	return v end  local function rgbdec2lum( R, G, B ) 	if ( 0 <= R and R < 256 and 0 <= G and G < 256 and 0 <= B and B < 256 ) then 		return 0.2126 * sRGB(R/255) + 0.7152 * sRGB(G/255) + 0.0722 * sRGB(B/255) 	else 		return '' 	end end  local function hsl2lum( h, s, l ) 	if ( 0 <= h and h < 360 and 0 <= s and s <= 1 and 0 <= l and l <= 1 ) then 		local c = (1 - math.abs(2*l - 1))*s 		local x = c*(1 - math.abs( math.fmod(h/60, 2) - 1) ) 		local m = l - c/2  		local r, g, b = m, m, m 		if( 0 <= h and h < 60 ) then 			r = r + c 			g = g + x 		elseif( 60 <= h and h < 120 ) then 			r = r + x 			g = g + c 		elseif( 120 <= h and h < 180 ) then 			g = g + c 			b = b + x 		elseif( 180 <= h and h < 240 ) then 			g = g + x 			b = b + c 		elseif( 240 <= h and h < 300 ) then 			r = r + x 			b = b + c 		elseif( 300 <= h and h < 360 ) then 			r = r + c 			b = b + x 		end 		return rgbdec2lum(255*r, 255*g, 255*b) 	else 		return '' 	end end  local function color2lum( c )  	if (c == nil) then 		return '' 	end 	-- whitespace 	c = c:match( '^%s*(.-)[%s;]*$' )  	-- unstrip nowiki strip markers 	c = mw.text.unstripNoWiki(c)  	-- lowercase 	c = c:lower()  	-- first try to look it up 	local L = HTMLcolor[c] 	if (L ~= nil) then 		return L 	end     	-- convert from hsl    	if mw.ustring.match(c,'^hsl%([%s]*[0-9][0-9%.]*[%s]*,[%s]*[0-9][0-9%.]*%%[%s]*,[%s]*[0-9][0-9%.]*%%[%s]*%)$') then 		local h, s, l = mw.ustring.match(c,'^hsl%([%s]*([0-9][0-9%.]*)[%s]*,[%s]*([0-9][0-9%.]*)%%[%s]*,[%s]*([0-9][0-9%.]*)%%[%s]*%)$') 		return hsl2lum(tonumber(h), tonumber(s)/100, tonumber(l)/100)    	end     	-- convert from rgb    	if mw.ustring.match(c,'^rgb%([%s]*[0-9][0-9]*[%s]*,[%s]*[0-9][0-9]*[%s]*,[%s]*[0-9][0-9]*[%s]*%)$') then 		local R, G, B = mw.ustring.match(c,'^rgb%([%s]*([0-9][0-9]*)[%s]*,[%s]*([0-9][0-9]*)[%s]*,[%s]*([0-9][0-9]*)[%s]*%)$') 		return rgbdec2lum(tonumber(R), tonumber(G), tonumber(B))    	end     	-- convert from rgb percent    	if mw.ustring.match(c,'^rgb%([%s]*[0-9][0-9%.]*%%[%s]*,[%s]*[0-9][0-9%.]*%%[%s]*,[%s]*[0-9][0-9%.]*%%[%s]*%)$') then 		local R, G, B = mw.ustring.match(c,'^rgb%([%s]*([0-9][0-9%.]*)%%[%s]*,[%s]*([0-9][0-9%.]*)%%[%s]*,[%s]*([0-9][0-9%.]*)%%[%s]*%)$') 		return rgbdec2lum(255*tonumber(R)/100, 255*tonumber(G)/100, 255*tonumber(B)/100)    	end  	-- remove leading # (if there is one) and whitespace 	c = mw.ustring.match(c, '^[%s#]*([a-f0-9]*)[%s]*$')  	-- split into rgb 	local cs = mw.text.split(c or '', '') 	if( #cs == 6 ) then 		local R = 16*tonumber('0x' .. cs[1]) + tonumber('0x' .. cs[2]) 		local G = 16*tonumber('0x' .. cs[3]) + tonumber('0x' .. cs[4]) 		local B = 16*tonumber('0x' .. cs[5]) + tonumber('0x' .. cs[6])  		return rgbdec2lum(R, G, B) 	elseif ( #cs == 3 ) then 		local R = 16*tonumber('0x' .. cs[1]) + tonumber('0x' .. cs[1]) 		local G = 16*tonumber('0x' .. cs[2]) + tonumber('0x' .. cs[2]) 		local B = 16*tonumber('0x' .. cs[3]) + tonumber('0x' .. cs[3])  		return rgbdec2lum(R, G, B) 	end  	-- failure, return blank 	return '' end  function p._greatercontrast(args) 	local bias = tonumber(args['bias'] or '0') or 0 	local v1 = color2lum(args[1] or '') 	local c2 = args[2] or '#FFFFFF' 	local v2 = color2lum(c2) 	local c3 = args[3] or '#000000' 	local v3 = color2lum(c3) 	local ratio1 = 0; 	local ratio2 = 0; 	if (type(v1) == 'number' and type(v2) == 'number') then 		ratio1 = (v2 + 0.05)/(v1 + 0.05) 		ratio1 = (ratio1 < 1) and 1/ratio1 or ratio1 	end 	if (type(v1) == 'number' and type(v3) == 'number') then 		ratio2 = (v3 + 0.05)/(v1 + 0.05) 		ratio2 = (ratio2 < 1) and 1/ratio2 or ratio2 	end 	return (ratio1 + bias > ratio2) and c2 or c3 end  function p._ratio(args) 	local v1 = color2lum(args[1]) 	local v2 = color2lum(args[2]) 	if (type(v1) == 'number' and type(v2) == 'number') then 		-- v1 should be the brighter of the two. 		if v2 > v1 then 			v1, v2 = v2, v1 		end 		return (v1 + 0.05)/(v2 + 0.05) 	else 		return args['error'] or '?' 	end end  function p._styleratio(args) 	local style = (args[1] or ''):lower() 	local bg, fg = 'white', 'black' 	local lum_bg, lum_fg = 1, 0  	if args[2] then 		local lum = color2lum(args[2]) 		if lum ~= '' then bg, lum_bg = args[2], lum end 	end 	if args[3] then 		local lum = color2lum(args[3]) 		if lum ~= '' then fg, lum_fg = args[3], lum end 	end  	local slist = mw.text.split(style or '', ';') 	for k = 1,#slist do 		s = slist[k] 		local k,v = s:match( '^[%s]*([^:]-):([^:]-)[%s;]*$' ) 		k = k or '' 		v = v or '' 		if (k:match('^[%s]*(background)[%s]*$') or k:match('^[%s]*(background%-color)[%s]*$')) then 			local lum = color2lum(v) 			if( lum ~= '' ) then bg, lum_bg = v, lum end 		elseif (k:match('^[%s]*(color)[%s]*$')) then 			local lum = color2lum(v) 			if( lum ~= '' ) then bg, lum_fg = v, lum end 		end 	end 	if lum_bg > lum_fg then 		return (lum_bg + 0.05)/(lum_fg + 0.05) 	else 		return (lum_fg + 0.05)/(lum_bg + 0.05) 	end end  function p.lum(frame) 	return color2lum(frame.args[1] or frame:getParent().args[1]) end  function p.ratio(frame) 	local args = frame.args[1] and frame.args or frame:getParent().args 	return p._ratio(args) end  function p.styleratio(frame) 	local args = frame.args[1] and frame.args or frame:getParent().args 	return p._styleratio(args) end  function p.greatercontrast(frame) 	local args = frame.args[1] and frame.args or frame:getParent().args 	return p._greatercontrast(args) end  return p