Difference between revisions of "Module:Color contrast"

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(rudimentary CSS parser)
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Line 1: Line 1:
 
--
 
--
−
-- This module implements  
+
-- This module implements
 
--  {{Color contrast ratio}}
 
--  {{Color contrast ratio}}
 
--  {{Greater color contrast ratio}}
 
--  {{Greater color contrast ratio}}
Line 9: Line 9:
 
local HTMLcolor = mw.loadData( 'Module:Color contrast/colors' )
 
local HTMLcolor = mw.loadData( 'Module:Color contrast/colors' )
  
−
local function sRGB ( v )  
+
local function sRGB (v)
−
if (v <= 0.03928) then  
+
if (v <= 0.03928) then
 
v = v / 12.92
 
v = v / 12.92
 
else
 
else
Line 18: Line 18:
 
end
 
end
  
−
local function rgbdec2lum( R, G, B )
+
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
 
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)
 
return 0.2126 * sRGB(R/255) + 0.7152 * sRGB(G/255) + 0.0722 * sRGB(B/255)
Line 26: Line 26:
 
end
 
end
  
−
local function hsl2lum( h, s, l )
+
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
 
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 c = (1 - math.abs(2*l - 1))*s
Line 58: Line 58:
 
end
 
end
  
−
local function color2lum( c )
+
local function color2lum(c)
  
 
if (c == nil) then
 
if (c == nil) then
 
return ''
 
return ''
 
end
 
end
 +
 +
-- html '#' entity
 +
c = c:gsub("&#35;", "#")
 +
 
-- whitespace
 
-- whitespace
 
c = c:match( '^%s*(.-)[%s;]*$' )
 
c = c:match( '^%s*(.-)[%s;]*$' )
 +
 +
-- unstrip nowiki strip markers
 +
c = mw.text.unstripNoWiki(c)
  
 
-- lowercase
 
-- lowercase
Line 75: Line 82:
 
end
 
end
  
−
  -- convert from hsl
+
-- 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]*%)$') then
+
if mw.ustring.match(c,'^hsl%([%s]*[0-9][0-9%.]*[%s]*,[%s]*[0-9][0-9%.]*%%[%s]*,[%s]*[0-9][0-9%.]*%%[%s]*%)$') 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]*%)$')
 
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)
 
return hsl2lum(tonumber(h), tonumber(s)/100, tonumber(l)/100)
−
  end
+
end
  
−
  -- convert from rgb
+
-- 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]*%)$') then
+
if mw.ustring.match(c,'^rgb%([%s]*[0-9][0-9]*[%s]*,[%s]*[0-9][0-9]*[%s]*,[%s]*[0-9][0-9]*[%s]*%)$') 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]*%)$')
 
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))
 
return rgbdec2lum(tonumber(R), tonumber(G), tonumber(B))
−
  end
+
end
  
−
  -- convert from rgb percent
+
-- 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]*%)$') then
+
if mw.ustring.match(c,'^rgb%([%s]*[0-9][0-9%.]*%%[%s]*,[%s]*[0-9][0-9%.]*%%[%s]*,[%s]*[0-9][0-9%.]*%%[%s]*%)$') 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]*%)$')
 
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)
 
return rgbdec2lum(255*tonumber(R)/100, 255*tonumber(G)/100, 255*tonumber(B)/100)
−
  end
+
end
  
 
-- remove leading # (if there is one) and whitespace
 
-- remove leading # (if there is one) and whitespace
Line 114: Line 121:
 
-- failure, return blank
 
-- failure, return blank
 
return ''
 
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
 
end
  
 
function p._greatercontrast(args)
 
function p._greatercontrast(args)
 
local bias = tonumber(args['bias'] or '0') or 0
 
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 v1 = color2lum(args[1] or '')
 
local c2 = args[2] or '#FFFFFF'
 
local c2 = args[2] or '#FFFFFF'
Line 123: Line 137:
 
local c3 = args[3] or '#000000'
 
local c3 = args[3] or '#000000'
 
local v3 = color2lum(c3)
 
local v3 = color2lum(c3)
−
local ratio1 = 0;
+
local ratio1 = -1;
−
local ratio2 = 0;
+
local ratio2 = -1;
 
if (type(v1) == 'number' and type(v2) == 'number') then
 
if (type(v1) == 'number' and type(v2) == 'number') then
 
ratio1 = (v2 + 0.05)/(v1 + 0.05)
 
ratio1 = (v2 + 0.05)/(v1 + 0.05)
Line 133: Line 147:
 
ratio2 = (ratio2 < 1) and 1/ratio2 or ratio2
 
ratio2 = (ratio2 < 1) and 1/ratio2 or ratio2
 
end
 
end
−
return (ratio1 + bias > ratio2) and c2 or c3
+
 
 +
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
 
end
  
Line 164: Line 196:
 
end
 
end
  
−
local slist = mw.text.split(style or '', ';')
+
local slist = mw.text.split(mw.ustring.gsub(mw.ustring.gsub(style or '', '&#[Xx]23;', '#'), '&#35;', '#'), ';')
 
for k = 1,#slist do
 
for k = 1,#slist do
−
s = slist[k]
+
local s = slist[k]
 
local k,v = s:match( '^[%s]*([^:]-):([^:]-)[%s;]*$' )
 
local k,v = s:match( '^[%s]*([^:]-):([^:]-)[%s;]*$' )
 
k = k or ''
 
k = k or ''
Line 185: Line 217:
 
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)
 
function p.lum(frame)
−
return color2lum(frame.args[1] or frame:getParent().args[1])
+
local color = frame.args[1] or frame:getParent().args[1]
 +
return p._lum(color)
 
end
 
end
  
Line 202: Line 242:
 
local args = frame.args[1] and frame.args or frame:getParent().args
 
local args = frame.args[1] and frame.args or frame:getParent().args
 
return p._greatercontrast(args)
 
return p._greatercontrast(args)
−
end
 
−
 
−
-- warning: crude! may be fooled by sufficientry tricky CSS
 
−
function p.extract_css_colors(css, e)
 
−
local fgcolor, bgcolor
 
−
 
−
css = css:gsub("/%*.-%*/", "")
 
−
for name, value in string.gmatch(css, "([a-z-]*)%s*:%s*([^;]*)") do
 
−
value = mw.text.trim(value)
 
−
if name == 'color' then
 
−
fgcolor = value
 
−
elseif name == 'background-color' then
 
−
bgcolor = value
 
−
elseif name == 'background' then
 
−
value = value:gsub("url%((['\"]?).-%1%)", "")
 
−
bgcolor = value:match("#[0-9A-Fa-f]*") or value:match("rgba?%([0-9.%, ]*%)") or value:match("hsla?%([0-9.%, ]*%)")
 
−
if not bgcolor then
 
−
value = value:gsub("[0-9.][0-9.]*[%%a-z][a-z]?[a-z]?", "")
 
−
value = value:gsub("auto", ""):gsub("cover", ""):gsub("contain", "")
 
−
value = value:gsub("scroll", ""):gsub("fixed", ""):gsub("local", "")
 
−
value = value:gsub("left", ""):gsub("right", ""):gsub("top", ""):gsub("bottom", ""):gsub("center", "")
 
−
value = value:gsub("no%-repeat", ""):gsub("repeat", ""):gsub("repeat%-[xy]", ""):gsub("space", ""):gsub("round", "")
 
−
value = value:gsub("border%-box", ""):gsub("padding%-box", ""):gsub("content%-box", "")
 
−
bgcolor = mw.text.trim(value)
 
−
end
 
−
end
 
−
end
 
−
 
−
return fgcolor, bgcolor
 
 
end
 
end
  
 
return p
 
return p

Latest revision as of 14:33, 9 March 2020

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

	-- 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
Retrieved from "https://www.annadreambrush.com/wiki/index.php?title=Module:Color_contrast&oldid=325"