Difference between revisions of "Module:Color contrast"

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(Undid revision 757931345 by Frietjes (talk))
 
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Line 2: Line 2:
 
-- This module implements  
 
-- This module implements  
 
--  {{Color contrast ratio}}
 
--  {{Color contrast ratio}}
 +
--  {{Greater color contrast ratio}}
 
--  {{ColorToLum}}
 
--  {{ColorToLum}}
 
--  {{RGBColorToLum}}
 
--  {{RGBColorToLum}}
 
--
 
--
 
local p = {}
 
local p = {}
 +
local HTMLcolor = mw.loadData( 'Module:Color contrast/colors' )
  
 
local function sRGB ( v )  
 
local function sRGB ( v )  
Line 12: Line 14:
 
else
 
else
 
v = math.pow((v+0.055)/1.055, 2.4)
 
v = math.pow((v+0.055)/1.055, 2.4)
    end
+
end
 
return v
 
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
 
end
  
 
local function color2lum( c )
 
local function color2lum( c )
+
 
 
if (c == nil) then
 
if (c == nil) then
 
return ''
 
return ''
 
end
 
end
 +
-- whitespace
 +
c = c:match( '^%s*(.-)[%s;]*$' )
  
local HTMLcolor = {
+
-- unstrip nowiki strip markers
white = 1,
+
c = mw.text.unstripNoWiki(c)
silver = 0.52711512570581,
 
gray = 0.2158605001139,
 
black = 0,
 
red = 0.2126,
 
maroon = 0.045891942324215,
 
yellow = 0.9278,
 
olive = 0.20027537200568,
 
lime = 0.7152,
 
green = 0.15438342968146,
 
aqua = 0.7874,
 
teal = 0.16996855778968,
 
blue = 0.0722,
 
navy = 0.015585128108224,
 
fuchsia = 0.2848,
 
purple = 0.061477070432439,
 
orange = 0.4817026703631,
 
  
gold = 0.69860877428159,
 
pink = 0.63271070702466,
 
lightpink = 0.58566152734898,
 
hotpink = 0.34658438169715,
 
deeppink = 0.23866895828276,
 
palevioletred = 0.28754994117889,
 
mediumvioletred = 0.14371899849357,
 
lightsalmon = 0.4780675225206,
 
salmon = 0.36977241527596,
 
darksalmon = 0.40541471563381,
 
lightcoral = 0.35522120733135,
 
indianred = 0.21406134963884,
 
crimson = 0.16042199953026,
 
firebrick = 0.10724525535015,
 
darkred = 0.054889674531132,
 
orangered = 0.25516243753416,
 
tomato = 0.30638612719415,
 
coral = 0.37017930872924,
 
darkorange = 0.40016167026524,
 
lightyellow = 0.98161818392882,
 
lemonchiffon = 0.94038992245622,
 
lightgoldenrodyellow = 0.93348351018297,
 
papayawhip = 0.87797100199835,
 
moccasin = 0.80083000991567,
 
peachpuff = 0.74905589878251,
 
palegoldenrod = 0.78792647887614,
 
khaki = 0.77012343394121,
 
darkkhaki = 0.45747326349994,
 
cornsilk = 0.93562110372965,
 
blanchedalmond = 0.85084439608156,
 
bisque = 0.80732327372979,
 
navajowhite = 0.76519682342785,
 
wheat = 0.74909702820482,
 
burlywood = 0.51559844533893,
 
tan = 0.48237604163921,
 
rosybrown = 0.32319457649407,
 
sandybrown = 0.46628543696283,
 
goldenrod = 0.41919977809569,
 
darkgoldenrod = 0.27264703559993,
 
peru = 0.30113074877936,
 
chocolate = 0.23898526114557,
 
saddlebrown = 0.097922285020521,
 
sienna = 0.13697631337098,
 
brown = 0.098224287876511,
 
}
 
    -- whitespace
 
    c = c:match( '^%s*(.-)%s*$' )
 
   
 
 
-- lowercase
 
-- lowercase
 
c = c:lower()
 
c = c:lower()
+
 
 
-- first try to look it up
 
-- first try to look it up
 
local L = HTMLcolor[c]
 
local L = HTMLcolor[c]
Line 97: Line 77:
 
return L
 
return L
 
end
 
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
 
-- remove leading # (if there is one) and whitespace
 
c = mw.ustring.match(c, '^[%s#]*([a-f0-9]*)[%s]*$')
 
c = mw.ustring.match(c, '^[%s#]*([a-f0-9]*)[%s]*$')
Line 103: Line 102:
 
local cs = mw.text.split(c or '', '')
 
local cs = mw.text.split(c or '', '')
 
if( #cs == 6 ) then
 
if( #cs == 6 ) then
local R = sRGB( (16*tonumber('0x' .. cs[1]) + tonumber('0x' .. cs[2]))/255 )
+
local R = 16*tonumber('0x' .. cs[1]) + tonumber('0x' .. cs[2])
local G = sRGB( (16*tonumber('0x' .. cs[3]) + tonumber('0x' .. cs[4]))/255 )
+
local G = 16*tonumber('0x' .. cs[3]) + tonumber('0x' .. cs[4])
local B = sRGB( (16*tonumber('0x' .. cs[5]) + tonumber('0x' .. cs[6]))/255 )
+
local B = 16*tonumber('0x' .. cs[5]) + tonumber('0x' .. cs[6])
+
 
L = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
return rgbdec2lum(R, G, B)
return L
 
 
elseif ( #cs == 3 ) then
 
elseif ( #cs == 3 ) then
local R = sRGB( (16*tonumber('0x' .. cs[1]) + tonumber('0x' .. cs[1]))/255 )
+
local R = 16*tonumber('0x' .. cs[1]) + tonumber('0x' .. cs[1])
local G = sRGB( (16*tonumber('0x' .. cs[2]) + tonumber('0x' .. cs[2]))/255 )
+
local G = 16*tonumber('0x' .. cs[2]) + tonumber('0x' .. cs[2])
local B = sRGB( (16*tonumber('0x' .. cs[3]) + tonumber('0x' .. cs[3]))/255 )
+
local B = 16*tonumber('0x' .. cs[3]) + tonumber('0x' .. cs[3])
+
 
L = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
return rgbdec2lum(R, G, B)
return L
 
 
end
 
end
+
 
 
-- failure, return blank
 
-- failure, return blank
 
return ''
 
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
 
end
  
 
function p._ratio(args)
 
function p._ratio(args)
local v1 = color2lum(c[1])
+
local v1 = color2lum(args[1])
local v2 = color2lum(c[2])
+
local v2 = color2lum(args[2])
 
if (type(v1) == 'number' and type(v2) == 'number') then
 
if (type(v1) == 'number' and type(v2) == 'number') then
return (v2 + 0.05)/(v1 + 0.05)
+
-- 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
 
else
 
return args['error'] or '?'
 
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
 
end
 
end
Line 140: Line 196:
 
return p._ratio(args)
 
return p._ratio(args)
 
end
 
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
 
return p

Latest revision as of 08:22, 2 January 2017

Documentation for this module may be created at Module:Color contrast/doc

--
-- 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