Module:Box-header

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This module creates the header section for boxed content. It implements {{box-header}}. It is intended to mainly be used in portals, but can also be used elsewhere.

Usage

{{#invoke:Box-header|boxHeader}}

For use in templates; calls _boxHeader with the parameters passed to the template as arguments.

{{#invoke:Box-header|_boxHeader|args}}

For use in modules; constructs the box header (and the start of the box body). The args are the parameters accepted by Template:Box-header. (The output may need to be expanded, depending on the values in the args.)

{{#invoke:Box-header|autoColour}}

For use in templates; calls _autoColour with the parameters passed to the template as arguments.

{{#invoke:Box-header|_autoColour|args}}

For use in modules; calculates appropriate colours for the box header, and then constructs it using _boxHeader. The args are the parameters accepted by Template:Box-header colour – the same as for Template:Box-header, apart from those specifying colours and the title. (The output may need to be expanded, depending on the values in the args.)

See also

The above documentation is transcluded from Module:Box-header/doc. (edit | history)
Editors can experiment in this module's sandbox (edit | diff) and testcases (create) pages.
Subpages of this module.

local p = {}
local colourContrastModule = require('Module:Color contrast')
local hex = require( 'luabit.hex' )
local function toPaddedHex(number)
	local prefixedHex = hex.to_hex(number) -- prefixed with '0x'
	local padding =  #prefixedHex == 3 and '0' or '' 
	return mw.ustring.gsub(prefixedHex, '0x', padding)
end

local defaults = {
	lightest = { sat=0.10, val=1.00, whiteText=false },
	light    = { sat=0.15, val=0.95, whiteText=false },
	normal   = { sat=0.40, val=0.85, whiteText=false },
	dark     = { sat=0.90, val=0.70, whiteText=true  },
	darkest  = { sat=1.00, val=0.45, whiteText=true  }
}


local function boxHeader(args)
	-- TODO
	return nil
end

local function boxBody(args)
	-- TODO
	return nil
end

local function HSVtoRGB(H, S, V) -- per [[HSL and HSV#Converting_to_RGB]]
	local C = V * S
	local H_prime = H / 60
	local X = X * ( 1 - math.abs(math.fmod(H_prime, 2) - 1) )
	local R1, G1, B1
	if H_prime <= 1 then
		R1 = C
		G1 = X
		B1 = 0
	elseif H_prime <= 2 then
		R1 = X
		G1 = C
		B1 = 0
	elseif H_prime <= 3 then
		R1 = 0
		G1 = C
		B1 = X
	elseif H_prime <= 4 then
		R1 = 0
		G1 = X
		B1 = C
	elseif H_prime <= 5 then
		R1 = X
		G1 = 0
		B1 = C
	elseif H_prime <= 6 then
		R1 = C
		G1 = 0
		B1 = X
	end	
	local m = V - C
	local R = R1 + m
	local G = G1 + m
	local B = B1 + m

	return '#' .. toPaddedHex(R) .. toPaddedHex(G) .. toPaddedHex(B)
end

local function calculateColour(H, S, V, whiteText, minContrast)
	local bgColour = HSVtoRGB(H, S, V)
	local textColour = whiteText and '#FFFFFF' or '#000000'
	local contrast = colourContrastModule._ratio({ bgColour, textColour })
	if contrast >= minContrast then
		return bgColour
	elseif whiteText then
		-- make the background darker and slightly increase the saturation
		return calculateColours(H, math.min(1, S+0.01), math.max(0, V-0.03), whiteText)
	else
		-- make the background lighter and slightly decrease the saturation
		return calculateColours(H, math.max(0, S-0.01), math.min(1, V+0.03), whiteText)
	end
end

local function makeColours(hue, description)
	local border = HSVtoRGB(hue, 0.15, 0.75)
	local titleForeground = defaults[description].whiteText and '#FFFFFF' or '#000000'
	local titleBackground = calculateColour(hue, defaults[description].sat, defaults[description].val, whiteText, 0.45)
	local contentForeground = '#000000'
	local contentBackground = calculateColour(hue, defaults[description].sat, defaults[description].val, whiteText, 0.7)
	return border, titleForeground, titleBackground, contentForeground, contentBackground
end

local function hueFromRGB(R, G, B) -- per [[HSL and HSV#Hue and chroma]]
	local M = v.max(R, G, B)
	local m = math.min(R, G, B)
	local C = M - m
	local H_prime
	if M == R then
		H_prime = math.fmod((G - B)/C, 6)
	elseif M == G then
		H_prime = (B - R)/C + 2
	elseif M == B then
		H_prime = (R - G)/C + 4
	end
	local H = 60 * H_prime
	return H
end

return p