Module:Color contrast
From Zoophilia Wiki
 | This module is rated as ready for general use. It has reached a mature form and is thought to be bug-free and ready for use wherever appropriate. It is ready to mention on help pages and other Wikipedia resources as an option for new users to learn. To reduce server load and bad output, it should be improved by sandbox testing rather than repeated trial-and-error editing. |
 | This module is subject to page protection. It is a highly visible module in use by a very large number of pages, or is substituted very frequently. Because vandalism or mistakes would affect many pages, and even trivial editing might cause substantial load on the servers, it is protected from editing. |
 | This Lua module is used on approximately 388,000 pages, or roughly 5702% of all pages. To avoid major disruption and server load, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Consider discussing changes on the talk page before implementing them. |
 | This module depends on the following other modules: |
This module is used primarily by
- {{Color contrast ratio}}
- {{ColorToLum}} / {{RGBColorToLum}}
- {{Color contrast conformance}}
- {{Ensure AAA contrast ratio}}
- {{Ensure AA contrast ratio}}
- {{Greater color contrast ratio}}
It is also used for tracking within
and for documentation in
Usage
To use this module, you may use one of the above listed templates or invoke the module directly
To compute relative luminescence
{{ColorToLum|color}}or{{#invoke:Color contrast|lum|color}}
To compute a contrast ratio between two colors
{{Color contrast ratio|color1|color2|error=?}}or{{#invoke:Color contrast|ratio|color1|color2|error=?}}
To determine which of two colors (color2a and color2b) has the greater contrast ratio with a particular color (color1)
{{Greater color contrast ratio|color1|color2a|color2b}}or{{#invoke:Color contrast|greatercontrast|color1|color2a|color2b}}
To compute the contrast ratio between the background and text colors specified in a css style string
{{#invoke:Color contrast|styleratio|css style statement string|default background color|default text color}}
--
-- This module implements
-- {{Color contrast ratio}}
-- {{Greater color contrast ratio}}
-- {{ColorToLum}}
-- {{RGBColorToLum}}
--
local p = {}
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 color2lum( c )
if (c == nil) then
return ''
end
local HTMLcolor = {
white = 1,
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*$' )
-- lowercase
c = c:lower()
-- first try to look it up
local L = HTMLcolor[c]
if (L ~= nil) then
return L
end
-- remove leading # (if there is one) and whitespace
c = mw.ustring.match(c, '^[%s#]*([a-f0-9]*)[%s]*$')
-- split into rgb
local cs = mw.text.split(c or '', '')
if( #cs == 6 ) then
local R = sRGB( (16*tonumber('0x' .. cs[1]) + tonumber('0x' .. cs[2]))/255 )
local G = sRGB( (16*tonumber('0x' .. cs[3]) + tonumber('0x' .. cs[4]))/255 )
local B = sRGB( (16*tonumber('0x' .. cs[5]) + tonumber('0x' .. cs[6]))/255 )
L = 0.2126 * R + 0.7152 * G + 0.0722 * B
return L
elseif ( #cs == 3 ) then
local R = sRGB( (16*tonumber('0x' .. cs[1]) + tonumber('0x' .. cs[1]))/255 )
local G = sRGB( (16*tonumber('0x' .. cs[2]) + tonumber('0x' .. cs[2]))/255 )
local B = sRGB( (16*tonumber('0x' .. cs[3]) + tonumber('0x' .. cs[3]))/255 )
L = 0.2126 * R + 0.7152 * G + 0.0722 * B
return L
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.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.greatercontrast(frame)
local args = frame.args[1] and frame.args or frame:getParent().args
return p._greatercontrast(args)
end
return p
