From 9020a6f71e41f02e416f940ca84e4a15d703693d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Fri, 12 Jan 2024 19:43:20 +0100
Subject: [PATCH] [gtk3/wayland] Infer resizable edges for tiled windows if
 possible.

This fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1871627

All GTK3/4 apps on non-GNOME desktops aren't resizable if they are
tiled.

This patch makes the non-tiled edges resizable if we have per-edge
tiling, but not per-edge resizing information.

We might want to make all edges resizable, but that might not be fine
for tiling compositors.
---
 gdk/wayland/gdkwindow-wayland.c | 46 +++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index 2bbff80bee..f09f651ac7 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -1664,6 +1664,49 @@ should_use_fixed_size (GdkWindowState state)
                   GDK_WINDOW_STATE_TILED);
 }
 
+static gboolean
+has_per_edge_tiling_info (GdkWindowState state)
+{
+  return state & (GDK_WINDOW_STATE_TOP_TILED |
+                  GDK_WINDOW_STATE_RIGHT_TILED |
+                  GDK_WINDOW_STATE_BOTTOM_TILED |
+                  GDK_WINDOW_STATE_LEFT_TILED);
+}
+
+static GdkWindowState
+infer_edge_constraints (GdkWindowState state)
+{
+  if (state & (GDK_WINDOW_STATE_MAXIMIZED | GDK_WINDOW_STATE_FULLSCREEN))
+    return state;
+
+  if (!(state & GDK_WINDOW_STATE_TILED) || !has_per_edge_tiling_info (state))
+    return state |
+           GDK_WINDOW_STATE_TOP_RESIZABLE |
+           GDK_WINDOW_STATE_RIGHT_RESIZABLE |
+           GDK_WINDOW_STATE_BOTTOM_RESIZABLE |
+           GDK_WINDOW_STATE_LEFT_RESIZABLE;
+
+  if (!(state & GDK_WINDOW_STATE_TOP_TILED))
+    state |= GDK_WINDOW_STATE_TOP_RESIZABLE;
+  if (!(state & GDK_WINDOW_STATE_RIGHT_TILED))
+    state |= GDK_WINDOW_STATE_RIGHT_RESIZABLE;
+  if (!(state & GDK_WINDOW_STATE_BOTTOM_TILED))
+    state |= GDK_WINDOW_STATE_BOTTOM_RESIZABLE;
+  if (!(state & GDK_WINDOW_STATE_LEFT_TILED))
+    state |= GDK_WINDOW_STATE_LEFT_RESIZABLE;
+
+  return state;
+}
+
+static gboolean
+supports_native_edge_constraints (GdkWindowImplWayland *impl)
+{
+  struct gtk_surface1 *gtk_surface = impl->display_server.gtk_surface;
+  if (!gtk_surface)
+    return FALSE;
+  return gtk_surface1_get_version (gtk_surface) >= GTK_SURFACE1_CONFIGURE_EDGES_SINCE_VERSION;
+}
+
 static void
 gdk_wayland_window_handle_configure (GdkWindow *window,
                                      uint32_t   serial)
@@ -1712,6 +1755,9 @@ gdk_wayland_window_handle_configure (GdkWindow *window,
   new_state = impl->pending.state;
   impl->pending.state = 0;
 
+  if (!supports_native_edge_constraints (impl))
+    new_state = infer_edge_constraints (new_state);
+
   fixed_size = should_use_fixed_size (new_state);
 
   saved_size = (width == 0 && height == 0);