add example for termsize

examples/terminalsize.lua

@@ -0,0 +1,36 @@
+local sys = require("system")
+
+sys.autotermrestore()  -- set up auto restore of terminal settings on exit
+
+-- setup Windows console to handle ANSI processing
+sys.setconsoleflags(io.stdout, sys.getconsoleflags(io.stdout) + sys.COF_VIRTUAL_TERMINAL_PROCESSING)
+sys.setconsoleflags(io.stdin, sys.getconsoleflags(io.stdin) + sys.CIF_VIRTUAL_TERMINAL_INPUT)
+
+-- setup Posix to disable canonical mode and echo
+local of_attr = sys.tcgetattr(io.stdin)
+sys.setnonblock(io.stdin, true)
+sys.tcsetattr(io.stdin, sys.TCSANOW, {
+  lflag = of_attr.lflag - sys.L_ICANON - sys.L_ECHO, -- disable canonical mode and echo
+})
+
+
+-- generate string to move cursor horizontally
+-- positive goes right, negative goes left
+local function cursor_move_horiz(n)
+  if n == 0 then
+    return ""
+  end
+  return "\27[" .. (n > 0 and n or -n) .. (n > 0 and "C" or "D")
+end
+
+
+local w, h
+print("Change the terminal window size, press any key to exit")
+while not sys.readkey(0.2) do
+  local nw, nh = sys.termsize()
+  if w ~= nw or h ~= nh then
+    w, h = nw, nh
+    local text = "Terminal size: " .. w .. "x" .. h .. "     "
+    io.write(text .. cursor_move_horiz(-#text))
+  end
+end