View source for Module:Color contrast

You do not have permission to edit this page, for the following reasons:

This page is currently semi-protected and can be changed only by autoconfirmed users.

Semi-protection is sometimes needed to stop vandalism to popular pages. Most pages can be changed by anyone.
The reason for protection can be found in the protection log. If you can not find what you were looking for in the protection log, the page may have been moved after being protected.
If you have an account which is autoconfirmed, log in to change this page. If you do not have an account, you may create one. After some time passes and you get some changes, you will be able to change semi-protected pages.
You can talk about this page with other users if you have noticed a mistake or have a suggestion for a simple change. Start a new section on this page's talk page and type {{editsemiprotected}} followed by your request. An autoconfirmed user can then make the change for you.
You may also ask for this page to be unprotected if you do not think that it is needed anymore.

This page is currently protected from changing because it is transcluded in the following page, which is protected with the "cascading" option:

Template:Cite encyclopedia

You currently can not change pages on Wikipedia.

The ability to change pages on all Wikimedia wikis has been removed from this account, IP address or IP address range by ‪Jon Kolbert‬. The following reason(s) were given for this block:

Open proxy/Webhost: Visit the FAQ if you are affected

Your IP address is 178.128.105.246. This block began on 23:59, 30 October 2023 and has been set to finish on: 23:59, 30 September 2026.

You are not blocked from reading pages, only from changing or creating them.
If you have just clicked a red link, you were blocked from creating a new page as no article on that topic is there yet.

If you think you were not blocked fairly, you may make unblock requests or file appeals at meta:Steward requests/Global.

You can view and copy the source of this page.

--
-- 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

	-- html '#' entity
	c = c:gsub("&#35;", "#")

	-- 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

-- This exports the function for use in other modules.
-- The colour is passed as a string.
function p._lum(color)
	return color2lum(color)
end

function p._greatercontrast(args)
	local bias = tonumber(args['bias'] or '0') or 0
	local css = (args['css'] and args['css'] ~= '') and true or false
	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 = -1;
	local ratio2 = -1;
	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

	if css then
		local c1 = args[1] or ''
		if mw.ustring.match(c1, '^[A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9]$') or
			mw.ustring.match(c1, '^[A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9]$') then
				c1 = '#' .. c1
		end
		if mw.ustring.match(c2, '^[A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9]$') or
			mw.ustring.match(c2, '^[A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9]$') then
				c2 = '#' .. c2
		end
		if mw.ustring.match(v3, '^[A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9]$') or
			mw.ustring.match(v3, '^[A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9]$') then
				c3 = '#' .. c3
		end
		return 'background-color:' .. c1 .. '; color:' .. ((ratio1 > 0) and (ratio2 > 0) and ((ratio1 + bias > ratio2) and c2 or c3) or '') .. ';'
	end

	return (ratio1 > 0) and (ratio2 > 0) and ((ratio1 + bias > ratio2) and c2 or c3) or ''
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(mw.ustring.gsub(mw.ustring.gsub(style or '', '&#[Xx]23;', '#'), '&#35;', '#'), ';')
	for k = 1,#slist do
		local 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

--[[
Use {{#invoke:Color contrast|somecolor}} directly or
{{#invoke:Color contrast}} from a wrapper template.

Parameters:
	-- |1=	— required; A color to check.
--]]
function p.lum(frame)
	local color = frame.args[1] or frame:getParent().args[1]
	return p._lum(color)
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

Templates used on this page:

Template:High-use (change)
Template:Lua (view source) (semi-protected)
Template:Sandbox other (change)
Template:Template link (view source) (protected)
Template:Tl (view source) (protected)
Module:Color contrast/doc (change)
Module:High-use (change)
Module:List (view source) (protected)
Module:Lua banner (view source) (protected)
Module:Message box (view source) (protected)
Module:Message box/configuration (view source) (protected)
Module:Message box/ombox.css (view source) (protected)
Module:String (view source) (protected)
Module:TableTools (view source) (protected)
Module:Transclusion count (change)
Module:Transclusion count/data/C (change)
Module:Yesno (view source) (protected)

Return to Module:Color contrast

Retrieved from "https://simple.wikipedia.org/wiki/Module:Color_contrast"