From d74307223fda5a8677a56a35416bdb62d12cd203 Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Sat, 27 Mar 2021 21:05:27 +1100
Subject: [PATCH] [client] x11: set the window center via WM_SIZE_HINTS

Due to the confusing nature of the x11 protocol, bit_gravity and
win_gravity are not what they appear to be. These do not describe the
window position but rather the pixels/subwindows when the window is
resized. Instead set the gravity via the WM_SIZE_HINTS property which
all modern window managers should respect.
---
 client/displayservers/X11/x11.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/client/displayservers/X11/x11.c b/client/displayservers/X11/x11.c
index 4a4d74d1..46112457 100644
--- a/client/displayservers/X11/x11.c
+++ b/client/displayservers/X11/x11.c
@@ -138,18 +138,6 @@ static bool x11Init(const LG_DSInitParams params)
   }
 #endif
 
-  swaMask |= CWBitGravity | CWWinGravity;
-  if (params.center)
-  {
-    swa.bit_gravity = CenterGravity;
-    swa.win_gravity = CenterGravity;
-  }
-  else
-  {
-    swa.bit_gravity = NorthWestGravity;
-    swa.win_gravity = NorthWestGravity;
-  }
-
   x11.window = XCreateWindow(
       x11.display,
       XDefaultRootWindow(x11.display),
@@ -179,6 +167,15 @@ static bool x11Init(const LG_DSInitParams params)
   free(hint.res_name);
   free(hint.res_class);
 
+  if (params.center)
+  {
+    XSizeHints *xsh = XAllocSizeHints();
+    xsh->flags       = PWinGravity;
+    xsh->win_gravity = 5; //Center
+    XSetWMNormalHints(x11.display, x11.window, xsh);
+    XFree(xsh);
+  }
+
   X11AtomsInit();
   XSetWMProtocols(x11.display, x11.window, &x11atoms.WM_DELETE_WINDOW, 1);