Setup basic layout system

- add Enter event bindings
- Add some more window bindings.

src/xcb/window.ml

@@ -6,9 +6,10 @@ let _xcb_change_window_attributes_checked =
     (ptr Types.Connection.typ @-> Types.Window.typ @-> uint32_t @-> ptr uint32_t
     @-> returning Types.Cookie.Void.typ)
 
-let values =
-  CArray.of_list uint32_t
-    [ Unsigned.UInt32.of_int (1048576 lor 524288 lor 131072 lor 4194304) ]
+let event_mask =
+  (1 lsl 4) lor (1 lsl 17) lor (1 lsl 19) lor (1 lsl 20) lor (1 lsl 22)
+
+let values = CArray.of_list uint32_t [ Unsigned.UInt32.of_int event_mask ]
 
 let setup conn root =
   let cookie =
@@ -18,6 +19,42 @@ let setup conn root =
   in
   Error.check conn cookie
 
+let window_event_mask = 1 lsl 4
+
+let values_window =
+  CArray.of_list uint32_t [ Unsigned.UInt32.of_int window_event_mask ]
+
+let setup_window conn window =
+  let cookie =
+    _xcb_change_window_attributes_checked conn window
+      (Unsigned.UInt32.of_int 2048)
+      (CArray.start values_window)
+  in
+  Error.check conn cookie
+
+let _xcb_configure_window =
+  foreign "xcb_configure_window"
+    (ptr Types.Connection.typ @-> Types.Window.typ @-> uint16_t @-> ptr uint32_t
+    @-> returning Types.Cookie.Void.typ)
+
+let reshape conn window x y width height =
+  let mask = (1 lsl 0) lor (1 lsl 1) lor (1 lsl 2) lor (1 lsl 3) in
+  let values =
+    CArray.of_list uint32_t
+      [
+        Unsigned.UInt32.of_int x;
+        Unsigned.UInt32.of_int y;
+        Unsigned.UInt32.of_int width;
+        Unsigned.UInt32.of_int height;
+      ]
+  in
+  let cookie =
+    _xcb_configure_window conn window
+      (Unsigned.UInt16.of_int mask)
+      (CArray.start values)
+  in
+  Error.check conn cookie
+
 let _xcb_grab_key =
   foreign "xcb_grab_key"
     (ptr Types.Connection.typ @-> uint8_t @-> Types.Window.typ @-> uint16_t
@@ -42,6 +79,18 @@ let map conn window =
   let cookie = _xcb_map_window conn window in
   Error.check conn cookie
 
+let _xcb_set_input_focus =
+  foreign "xcb_set_input_focus"
+    (ptr Types.Connection.typ @-> uint8_t @-> Types.Window.typ @-> uint32_t
+    @-> returning Types.Cookie.Void.typ)
+
+let focus conn window =
+  let cookie =
+    _xcb_set_input_focus conn (Unsigned.UInt8.of_int 0) window
+      (Unsigned.UInt32.of_int 0)
+  in
+  Error.check conn cookie
+
 let _xcb_kill_client =
   foreign "xcb_kill_client"
     (ptr Types.Connection.typ @-> Types.Window.typ