Handle meta_screen_get_monitor_for_point() returning NULL

On the X11 backend we don't track the pointer position in
priv->current_x/y which remain set to zero. That means we never set
the clutter stage cursor if point 0,0 isn't covered by any monitor
since we return early.

Commit 4bebc5e5fa8aade8a96c769bf2365abe0948f6ce introduced this to
avoid crashing on the prepare-at handlers when the cursor position
doesn't fall inside any monitor area but we can handle that higher up
in the stack. In that case, the sprite's scale doesn't matter since
the cursor won't be shown anyway so we can skip setting it.

https://bugzilla.gnome.org/show_bug.cgi?id=763159

3 files changed, 5 insertions, 18 deletions

diff --git a/src/backends/meta-cursor-renderer.c b/src/backends/meta-cursor-renderer.c
index a76241b9e..48cd239a9 100644
--- a/src/backends/meta-cursor-renderer.c
+++ b/src/backends/meta-cursor-renderer.c
@@ -27,8 +27,6 @@
 #include "meta-cursor-renderer.h"
 
 #include <meta/meta-backend.h>
-#include <backends/meta-backend-private.h>
-#include <backends/meta-monitor-manager-private.h>
 #include <meta/util.h>
 
 #include <cogl/cogl.h>
@@ -118,14 +116,6 @@ meta_cursor_renderer_calculate_rect (MetaCursorRenderer *renderer,
   };
 }
 
-static gboolean
-is_cursor_in_monitors_area (int x, int y)
-{
-  MetaMonitorManager *monitor_manager = meta_backend_get_monitor_manager (meta_get_backend ());
-  return meta_monitor_manager_get_monitor_at_point (monitor_manager,
-                                                    (gfloat) x, (gfloat) y) >= 0;
-}
-
 static void
 update_cursor (MetaCursorRenderer *renderer,
                MetaCursorSprite   *cursor_sprite)
@@ -134,11 +124,6 @@ update_cursor (MetaCursorRenderer *renderer,
   gboolean handled_by_backend;
   gboolean should_redraw = FALSE;
 
-  /* do not render cursor if it is not on any monitor. Such situation
-   * can occur e. g. after monitor hot-plug */
-  if (!is_cursor_in_monitors_area (priv->current_x, priv->current_y))
-    return;
-
   if (cursor_sprite)
     meta_cursor_sprite_prepare_at (cursor_sprite,
                                    priv->current_x,
diff --git a/src/core/screen.c b/src/core/screen.c
index 934b3af35..0e056b3ae 100644
--- a/src/core/screen.c
+++ b/src/core/screen.c
@@ -1233,7 +1233,8 @@ root_cursor_prepare_at (MetaCursorSprite *cursor_sprite,
   monitor = meta_screen_get_monitor_for_point (screen, x, y);
 
   /* Reload the cursor texture if the scale has changed. */
-  meta_cursor_sprite_set_theme_scale (cursor_sprite, monitor->scale);
+  if (monitor)
+    meta_cursor_sprite_set_theme_scale (cursor_sprite, monitor->scale);
 }
 
 static void
diff --git a/src/wayland/meta-wayland-pointer.c b/src/wayland/meta-wayland-pointer.c
index 2936afc7d..b8a138543 100644
--- a/src/wayland/meta-wayland-pointer.c
+++ b/src/wayland/meta-wayland-pointer.c
@@ -1011,8 +1011,9 @@ cursor_sprite_prepare_at (MetaCursorSprite *cursor_sprite,
   if (!meta_xwayland_is_xwayland_surface (surface))
     {
       monitor = meta_screen_get_monitor_for_point (screen, x, y);
-      meta_cursor_sprite_set_texture_scale (cursor_sprite,
-                                            (float)monitor->scale / surface->scale);
+      if (monitor)
+        meta_cursor_sprite_set_texture_scale (cursor_sprite,
+                                              (float)monitor->scale / surface->scale);
     }
   meta_wayland_surface_update_outputs (surface);
 }