!752

static Map<BWImage, S> chars;

static int luaMaxSteps = 100*1000*1000;

sS code = [[

  -- Input:

  --   iw = image of word to recognize

  --   chars = images of characters & description

  -- Output:

  --   what is recognized (a string)

  local threshold = 0.95

  -- helper function

  function roughMatch(ic, iw, x1)

    local w, h = iw.w, iw.h

    if ic.h ~= h then return false end

    local x2 = x1+ic.w

    if x2 > w then return false end

    local d = 0

    for x = x1, x2-1 do

      for y = 0, h-1 do

        d = d + math.abs(ic.getBrightness(x-x1, y)-iw.getBrightness(x, y))

      end

    end

    return 1-d/((x2-x1)*h)

  end

  -- main algorithm

  local buf = {}

  for x=0, iw.w-1 do

    for ic, c in pairs(chars) do

      if roughMatch(ic, iw, x) > threshold then

        table.insert(buf, c)

        x = x + ic.w-1

        goto xloop

      end

    end

    ::xloop::

  end

  return table.concat(buf)

  -- done

]];

static bool again() {

  ret false;

}

static S getParams() {

  ret structure(litmap("code", code));

}

static S recognizeWord(BWImage iw, O infos) {

  chars = (Map) quickImport(get(infos, "chars"));

  luaMaxSteps(luaMaxSteps);

  ret evalLua(makeSandbox(iw), code).tojstring();

}

static Sandbox makeSandbox(final BWImage img) {

  new LuaTable lChars;

  int i = 0;

  for (BWImage ic : keys(chars))

    lChars.set(bwImageToLua(ic), Lua.value(chars.get(ic)));

  ret luaSandbox(

    "iw", bwImageToLua(img),

    "chars", lChars);

}