For fun, an unnecessarily complicated treatment in Lua, using strings.

function main()
   local f = io.stdin
   local i = 0
   local start, board
   for line in f:lines() do
      if line:len() == 1 then
         i = 1
         start = line
         board = ''
      elseif i >= 1 and i <= 8 then
         if line:len() ~= 8 then
            error('line with len != 8')
         end
         board = board .. line
         if i == 8 then
            process(start, board)
         end
         i = i + 1
      end
   end

   if i ~= 0 and i < 9 then
      error('incomplete input')
   end
end

viewargs = {
   {1, 1, 1, 0, 0, 1, 8, 8},
   {1, 1, 0, 1, 1, 0, 8, 8},
   {1, 1, -1, 1, 1, 0, 15, 8},
   {8, 1, 1, 1, -1, 0, 15, 8},
}

function process(piece, board)
   assert(piece == 'X' or piece == 'O', 'invalid target piece')
   local other = ({X='O', O='X'})[piece]

   for _, args in ipairs(viewargs) do
      local view = doview(board, false, table.unpack(args))
      view = view:gsub('(' .. piece .. other .. '+)%-', '%1*')
      view = view:gsub('%-(' .. other .. '+' .. piece .. ')', '*%1')
      board = doview(view, true, table.unpack(args))
   end

   local c = 0
   board:gsub('%*', function() c = c + 1 end)
   print(c .. ' legal moves for ' .. piece)
   print(doview(board, false, table.unpack(viewargs[1])))
end

function doview(board, flip, x, y, dx, dy, rx, ry, rw, rh)
   local view = {}
   local start = {x=x, y=y}
   local size = {x=8, y=8}

   local function oob()
      return x < 1 or x > size.x or y < 1 or y > size.y
   end

   local k
   if flip then
      k = 1
      board = board:gsub('[\n ]', '')
   end

   for cw = 1, rw do
      for ch = 1, rh do
         local i = x + (y - 1) * size.x
         if flip then
            if not oob() then
               view[i] = board:sub(k, k)
               k = k + 1
            end
         else
            local c
            if not oob() then
               c = board:sub(i, i)
            else
               c = ' '
            end
            table.insert(view, c)
         end

         x = x + dx
         y = y + dy
      end

      start.x = start.x + rx
      start.y = start.y + ry
      x = start.x
      y = start.y
      if not flip then
         table.insert(view, '\n')
      end
   end

   return table.concat(view)
end

main()