get("#348") -- rgb and bright
get("#137") -- split
get("#390") -- msinsert

y, w, h = img.height-19, 20, 17
x = img.width-w
if y < 0 or y+h > img.height then return "No Battery Symbol" end

--[[
original icon:
YYYYYYYYYYYYYYYYYYYY
YYYYYYYYYYYYYYYYYYYY
YLCCCCCCCCCCCCCCLYXX
YEEEEEEEEEEEEEEEEYXX
XFFSVVVVVVVVVVSFFXXX
XGGUSSSSSSSSSSUGGXXX
XGGTSSSSSSSSSSTGGDHX
XHHTSSSSSSSSSSTHHHGX
XIITSSSSSSSSSSTIIIIX
WIITSSSSSSSSSSTIIINW
WJJTRRRRRRRRRRTJJXXW
WKKOSSSSSSSSSSOKKWWW
WLKHFFFFFFFFFFHKLWVV
VSMLLLLLLLLLLLLMSVVV
VWXXXXXXXXXXXXXXWVVV
VVVVVVVVVVVVVVVVVVVV
VVVVVVVVVVVVVVVVVVVV
]]

icon = [[
YYYYYYYYYYYYYYYYYYYY
YYYYYYYYYYYYYYYYYYYY
YLCCCCCCCCCCCCCCLYXX
YEEEEEEEEEEEEEEEEYXX
XFFS???????????FFXXX
XGGU???????????GGXXX
XGGT???????????GGDHX
XHHT???????????HHHGX
XIIT???????????IIIIX
WIIT???????????IIINW
WJJT???????????JJXXW
WKKO??????????OKKWWW
WLKHFFFFFFFFFFHKLWVV
VSMLLLLLLLLLLLLMSVVV
VWXXXXXXXXXXXXXXWVVV
VVVVVVVVVVVVVVVVVVVV
VVVVVVVVVVVVVVVVVVVV
]]

icon = split(icon, "\n")
innerPixels = {}

while x >= 0 do
  total, count = 0, 0
  for yy=y, y+h-1 do
    line = icon[yy-y+1]
    for xx=x, x+w-1 do
      pix = img.getInt(xx, yy)
      c = line:sub(xx-x+1, xx-x+1)
      if c == '?' then
        msinsert(innerPixels, pix)
      else
        b = math.floor(bright(rgb(pix))*25+0.5)
        lb = string.byte(c)-string.byte("A")
        diff = math.abs(b-lb)
        total, count = total+diff, count+1
      end
    end
  end
  
  sim = math.floor(100*(1-total/(count*25))+0.5)
  print("Similarity at x="..x..": "..sim.."%")
  
  if sim >= 99 then
    return "Battery Symbol: "..x..", "..y..", "..x+w..", "..y+h
  end
  x = x-1
end

x = nil
return "No Battery Symbol"

-- innerPixels and x, y, w, h are returned for including snippets

Began life as a copy of #361