Module:Rainbow

local p = {}

local function format_it(tbl, name) for i, v in ipairs(tbl) do		tbl[i] = string.format("%06x", tbl[i]) end p[name] = tbl end

local function mod(a, b)	return a - math.floor(a/b) * b end

-- takes hex color as string, gives back table local function colorTable(color) local clen = string.len(color) assert(clen >= 6 and clen <= 8) assert(string.gmatch("^"..("[0-9a-fA-F]"):rep(6)..("[0-9a-fA-F]?"):rep(2).."$", color)) local ret = {} ret["R"] = tonumber(color:sub(1,2), 16) ret["G"] = tonumber(color:sub(3,4), 16) ret["B"] = tonumber(color:sub(5,6), 16) ret["A"] = tonumber(color:sub(7,8), 16) or 255 return ret end local black = colorTable("000000") local white = colorTable("FFFFFF")

local function colorAsRGBA(colorTbl) return string.format("rgba(%.2f,%.2f,%.2f,%.2f)", 						 colorTbl["R"], colorTbl["G"], 						 colorTbl["B"], colorTbl["A"]) end

-- simple mix of two colors. t_ means target. percent is as float (.4=40%) local function colorMix(colorTbl, t_colorTbl, percent) local ret = {} local diff = {} diff["R"] = t_colorTbl["R"] - colorTbl["R"] diff["G"] = t_colorTbl["G"] - colorTbl["G"] diff["B"] = t_colorTbl["B"] - colorTbl["B"] diff["A"] = t_colorTbl["A"] - colorTbl["A"] ret["R"] = colorTbl["R"] + (diff["R"] * percent) ret["G"] = colorTbl["G"] + (diff["G"] * percent) ret["B"] = colorTbl["B"] + (diff["B"] * percent) ret["A"] = colorTbl["A"] + (diff["A"] * percent) return ret end

p.HTML = function(frame, page) local args = require('Module:Arguments').getArgs(frame) p.args = args local ret = '' local inp = args[1] if not inp then return nil end local steps = mw.ustring.len(inp) local repeat_ = (args["repeat"] and tonumber(args["repeat"])) or 1 local newcolors = {} if args.colors then for k = 1, repeat_, 1 do			nc = mw.text.gsplit(args.colors, ",", true)

for c in nc do				newcolors[#newcolors+1] = tonumber(c:sub(2, -1), 16) end end end

format_it(#newcolors > 0 and newcolors or	--        red       orange    yellow    green     blue      indigo-violet			  {0xFF0000, 0xFF7F00, 0xFFFF00, 0x00FF00, 0x0000FF, 0x8B00FF}, "roygbiv")

-- lua pattern from https://stackoverflow.com/questions/13235091/extract-the-first-letter-of-a-utf-8-string-with-lua local i = 0 for c in inp:gmatch("[%z\1-\127\194-\244][\128-\191]*") do		local color = colorTable(p.roygbiv[mod(i, #p.roygbiv)+1]) local s_per = steps / #p.roygbiv local j = (i / s_per) local jf = math.floor(j) if args.gradient then local cidx = mod(jf, #p.roygbiv)+1 if mod(cidx, 2) == 0 then cidx = cidx + 1 end if cidx > #p.roygbiv then cidx = #p.roygbiv end color = colorTable(p.roygbiv[cidx]) local tidx = mod(jf+1, #p.roygbiv)+1 if mod(tidx, 2) == 1 then tidx = tidx + 1 end if tidx > #p.roygbiv then tidx = cidx end local tcolor = colorTable(p.roygbiv[tidx]) color = colorMix(color, tcolor, mod(j, 1)) end local subdued = nil if args.theme then subdued = args.theme:match("^subdued(%d+)%%$") end if subdued then color = colorMix(color, black, tonumber(subdued) / 100) end assert(color) if args.bg ~= "y" then local rgba = colorAsRGBA(color) ret = (ret .. "" .. c .." ") else local rgba = colorAsRGBA(args.fgcolor and colorTable(args.fgcolor:sub(2, -1)) or black) ret = (ret .. "" .. c .." ") end i = i + 1 end return ret end

return p