From 0e56ebb51af7984cb029707ae3d32bdf1689992f Mon Sep 17 00:00:00 2001
From: Carlos Garnacho <carlosg@gnome.org>
Date: Fri, 17 Nov 2023 18:24:14 +0100
Subject: [PATCH] wayland: Avoid sending wl_pointer.motion on unchanged
 coordinates

This might happen for a variety of reasons, like monitor edges or
pointer constraints. Handle this naturally in MetaWaylandPointer for
all these cases.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3420>
---
 src/wayland/meta-wayland-pointer.c | 21 +++++++++++++++++----
 src/wayland/meta-wayland-pointer.h |  1 +
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/wayland/meta-wayland-pointer.c b/src/wayland/meta-wayland-pointer.c
index b7f668959..428394499 100644
--- a/src/wayland/meta-wayland-pointer.c
+++ b/src/wayland/meta-wayland-pointer.c
@@ -397,11 +397,18 @@ meta_wayland_pointer_send_motion (MetaWaylandPointer *pointer,
   meta_wayland_surface_get_relative_coordinates (pointer->focus_surface,
                                                  x, y, &sx, &sy);
 
-  wl_resource_for_each (resource, &pointer->focus_client->pointer_resources)
+  if (pointer->last_rel_x != sx ||
+      pointer->last_rel_y != sy)
     {
-      wl_pointer_send_motion (resource, time,
-                              wl_fixed_from_double (sx),
-                              wl_fixed_from_double (sy));
+      wl_resource_for_each (resource, &pointer->focus_client->pointer_resources)
+        {
+          wl_pointer_send_motion (resource, time,
+                                  wl_fixed_from_double (sx),
+                                  wl_fixed_from_double (sy));
+        }
+
+      pointer->last_rel_x = sx;
+      pointer->last_rel_y = sy;
     }
 
   meta_wayland_pointer_send_relative_motion (pointer, event);
@@ -469,6 +476,9 @@ meta_wayland_pointer_enable (MetaWaylandPointer *pointer)
                     "cursor-changed",
                     G_CALLBACK (meta_wayland_pointer_on_cursor_changed),
                     pointer);
+
+  pointer->last_rel_x = -FLT_MAX;
+  pointer->last_rel_y = -FLT_MAX;
 }
 
 void
@@ -966,6 +976,9 @@ meta_wayland_pointer_set_focus (MetaWaylandPointer *pointer,
   if (pointer->focus_surface == surface)
     return;
 
+  pointer->last_rel_x = -FLT_MAX;
+  pointer->last_rel_y = -FLT_MAX;
+
   if (pointer->focus_surface != NULL)
     {
       uint32_t serial;
diff --git a/src/wayland/meta-wayland-pointer.h b/src/wayland/meta-wayland-pointer.h
index 7fd8261e5..56001b2e7 100644
--- a/src/wayland/meta-wayland-pointer.h
+++ b/src/wayland/meta-wayland-pointer.h
@@ -66,6 +66,7 @@ struct _MetaWaylandPointer
   guint32 grab_serial;
   guint32 grab_time;
   float grab_x, grab_y;
+  float last_rel_x, last_rel_y;
 
   ClutterInputDevice *device;
   MetaWaylandSurface *current;