Module:G

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

-- Take a number and calculate how many steps in the gradient it is.
-- Output is a class name defined in MediaWiki:Common.css.

local yesno = require('Module:Yesno')
local p = {}

local bins = 15
local palette = 'diverging-red-blue'

p.main = function(frame)
	local val = tonumber(frame.args[1])
	if val == nil then return '' end
	local right = tonumber(frame.args['right']) or 100
	local left = tonumber(frame.args['left']) or right * -1
	local invert = yesno(frame.args['invert'], false)
	return p._main(val, left, right, invert)
end

p._main = function(val, left, right, invert)
	invert = invert or false
	local transformed = (val - left) * bins / (right - left)
	local bin_idx = math.max(0, math.min(bins - 1, math.floor(transformed)))
	if bin_idx == math.floor(bins / 2) then
		if val > 0 then
			bin_idx = bin_idx + 1
		elseif val < 0 then
			bin_idx = bin_idx - 1
		end
	end
	if invert then bin_idx = steps - 1 - bin_idx end
	return 'gradient_' .. palette .. '_' .. bin_idx
end

return p