--Efficient (fast) functions to implement cells in tables of weather data.Temperature conversion is built-in, but for simplicity, temperaturesare assumed to be for habitable locations (from -100 to 100 °C).
local MINUS = '−' -- Unicode U+2212 MINUS SIGN
local function temperature_style(palette, value, out_rgb) -- Return style for a table cell based on the given value which -- should be a temperature in °C. local function style(bg, fg) local min, max = unpack(palette.white or) if not fg and value and (value < min or value >= max) then fg = 'FFFFFF' end if fg then fg = 'color:#' .. fg .. ';' else fg = end return 'style="background:#' .. bg .. ';' .. fg .. ' font-size:100%;"' end if type(value) ~= 'number' then return style('FFFFFF', '000000') end local rgb = out_rgb or for i, v in ipairs(palette) do local a, b, c, d = unpack(v) if value <= a then rgb[i] = 0 elseif value < b then rgb[i] = (value - a) * 255 / (b - a) elseif value <= c then rgb[i] = 255 elseif value < d then rgb[i] = 255 - ((value - c) * 255 / (d - c)) else rgb[i] = 0 end end return style(string.format('%02X%02X%02X', rgb[1], rgb[2], rgb[3]))end
local function format_cell(palette, value, intext, outtext) -- Return one line of wikitext to make a cell in a table. if not value then return '|\n' end local text if outtext then text = intext .. '
(' .. outtext .. ')' else text = intext end return '| ' .. temperature_style(palette, value) .. ' | ' .. text .. '\n'end
local function process_temperature(intext, inunit, swap) --Convert °C to °F or vice versa, assuming the temperature is for a habitable location, well inside the range -100 to 100 °C. That simplifies determining precision and formatting (no commas are needed). Return (celsius_value, intext, outtext) if valid; otherwise return nil. The returned input and output are swapped if requested. Each returned string has a Unicode MINUS as sign, if negative. local invalue = tonumber(intext) if not invalue then return nil end local integer, dot, decimals = intext:match('^%s*%-?(%d+)(%.?)(%d*)%s*$') if not integer then return nil end if invalue < 0 then intext = MINUS .. integer .. dot .. decimals end local outtext if inunit
'F' then local celsius_value, outvalue if inunit
and 0 or #decimals outtext = string.format('%.' .. precision .. 'f', math.abs(outvalue) + 2e-14) if outvalue < 0 and tonumber(outtext) ~= 0 then -- Don't show minus if result is negative but rounds to zero. outtext = MINUS .. outtext end if swap then return celsius_value, outtext, intext end return celsius_value, intext, outtext end -- LATER Think about whether a no-conversion option would be useful. return invalue, intext, outtextend
local function temperature_row(palette, row, inunit, swap) --Return 13 lines specifying the style/content of 13 table cells. Input is 13 space-separated words, each a number (°C or °F). Any word that is not a number gives a blank cell ("M" for a missing cell). Any excess words are ignored. Function Input Output ------------------------ CtoF C C/F FfromC C F/C CfromF F C/F FtoC F F/C local nrcol = 13 local results, n =, 0 for word in row:gmatch('%S+') do n = n + 1 if n > nrcol then break end results[n] = format_cell(palette, process_temperature(word, inunit, swap)) end for i = n + 1, nrcol do results[i] = format_cell end return table.concat(results)end
local palettes =
local function temperatures(frame, inunit, swap) local palette = palettes[frame.args.palette] or palettes.cool return temperature_row(palette, frame.args[1], inunit, swap)end
local function CtoF(frame) return temperatures(frame, 'C')end
local function CfromF(frame) return temperatures(frame, 'F', true)end
local function FtoC(frame) return temperatures(frame, 'F')end
local function FfromC(frame) return temperatures(frame, 'C', true)end
local chart = width=600|height=180|xAxisTitle=Celsius|yAxisTitle=__COLOR|type=line|x=__XVALUES|y=__YVALUES|colors=__COLOR}}
local function show(frame) --For testing, return wikitext to show graphs of how the red/green/blue colors vary with temperature, and a table of the resulting colors. local function collection -- Return a table to hold items. return end local function make_chart(result, color, xvalues, yvalues) result:add('\n') result:add(frame:preprocess((chart:gsub('__[A-Z]+',)))) end local function with_minus(value) if value < 0 then return MINUS .. tostring(-value) end return tostring(value) end local args = frame.args local first = args[1] or -90 local last = args[2] or 59 local palette = palettes[args.palette] or palettes.cool local xvals, reds, greens, blues = collection, collection, collection, collection local wikitext = collection wikitext:add(class="wikitable"|-]] ) local columns = 0 for celsius = first, last do local rgb = local style = temperature_style(palette, celsius, rgb) local R = math.floor(rgb[1]) local G = math.floor(rgb[2]) local B = math.floor(rgb[3]) xvals:add(celsius) reds:add(R) greens:add(G) blues:add(B) wikitext:add('| ' .. style .. ' | ' .. with_minus(celsius) .. '\n') columns = columns + 1 if columns >= 10 then columns = 0 wikitext:add('|-\n') end end wikitext:add('|}\n') make_chart(wikitext, 'Red', xvals, reds) make_chart(wikitext, 'Green', xvals, greens) make_chart(wikitext, 'Blue', xvals, blues) return wikitext:joinend
return