display window on screen center

modules/client/client.lua

@@ -8,8 +8,14 @@ function Client.init()
   if g_window.getPlatformType() == "X11-EGL" then
     g_window.setFullscreen(true)
   else
-    g_window.move({ x=220, y=220 })
-    g_window.resize({ width=800, height=480 })
+    local size = { width = 1024,
+                   height = 768 }
+    g_window.resize(size)
+
+    local displaySize = g_window.getDisplaySize()
+    local pos = { x = (displaySize.width - size.width)/2,
+                  y = (displaySize.height - size.height)/2 }
+    g_window.move(pos)
   end
 
   g_window.setTitle('OTClient')