backends/x11: Draw our own cursor sprite when running nested

Use a specialized cursor renderer when running as a nested Wayand
compositor. This new renderer sets an empty X11 cursor and draws the
cursor as part of the stage using the generic cursor renderer drawing
path.

https://bugzilla.gnome.org/show_bug.cgi?id=744932

src/Makefile.am

@@ -96,6 +96,8 @@ libmutter_la_SOURCES =				\
 	backends/x11/meta-barrier-x11.h			\
 	backends/x11/meta-cursor-renderer-x11.c		\
 	backends/x11/meta-cursor-renderer-x11.h		\
+	backends/x11/nested/meta-cursor-renderer-x11-nested.c		\
+	backends/x11/nested/meta-cursor-renderer-x11-nested.h		\
 	backends/x11/meta-idle-monitor-xsync.c		\
 	backends/x11/meta-idle-monitor-xsync.h		\
 	backends/x11/meta-input-settings-x11.c		\

src/backends/x11/meta-backend-x11.c

@@ -40,6 +40,7 @@
 #include "meta-idle-monitor-xsync.h"
 #include "meta-monitor-manager-xrandr.h"
 #include "backends/meta-monitor-manager-dummy.h"
+#include "backends/x11/nested/meta-cursor-renderer-x11-nested.h"
 #include "meta-cursor-renderer-x11.h"
 #ifdef HAVE_WAYLAND
 #include "wayland/meta-wayland.h"
@@ -521,7 +522,20 @@ meta_backend_x11_create_monitor_manager (MetaBackend *backend)
 static MetaCursorRenderer *
 meta_backend_x11_create_cursor_renderer (MetaBackend *backend)
 {
+  MetaBackendX11 *x11 = META_BACKEND_X11 (backend);
+  MetaBackendX11Private *priv = meta_backend_x11_get_instance_private (x11);
+
+  switch (priv->mode)
+    {
+    case META_BACKEND_X11_MODE_COMPOSITOR:
       return g_object_new (META_TYPE_CURSOR_RENDERER_X11, NULL);
+      break;
+    case META_BACKEND_X11_MODE_NESTED:
+      return g_object_new (META_TYPE_CURSOR_RENDERER_X11_NESTED, NULL);
+      break;
+    default:
+      g_assert_not_reached ();
+    }
 }
 
 static gboolean

src/backends/x11/nested/meta-cursor-renderer-x11-nested.c

@@ -0,0 +1,88 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2015 Red Hat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * Written by:
+ *     Jonas Ådahl <jadahl@gmail.com>
+ */
+
+#include "config.h"
+
+#include "backends/x11/nested/meta-cursor-renderer-x11-nested.h"
+
+#include "backends/x11/meta-backend-x11.h"
+
+struct _MetaCursorRendererX11Nested
+{
+  MetaCursorRenderer parent;
+};
+
+GType meta_cursor_renderer_x11_nested_get_type (void) G_GNUC_CONST;
+
+G_DEFINE_TYPE (MetaCursorRendererX11Nested, meta_cursor_renderer_x11_nested,
+               META_TYPE_CURSOR_RENDERER);
+
+static gboolean
+meta_cursor_renderer_x11_nested_update_cursor (MetaCursorRenderer *renderer)
+{
+  return FALSE;
+}
+
+static Cursor
+create_empty_cursor (Display *xdisplay)
+{
+  XcursorImage *image;
+  XcursorPixel *pixels;
+  Cursor xcursor;
+
+  image = XcursorImageCreate (1, 1);
+  if (image == NULL)
+    return None;
+
+  image->xhot = 0;
+  image->yhot = 0;
+
+  pixels = image->pixels;
+  pixels[0] = 0;
+
+  xcursor = XcursorImageLoadCursor (xdisplay, image);
+  XcursorImageDestroy (image);
+
+  return xcursor;
+}
+
+static void
+meta_cursor_renderer_x11_nested_init (MetaCursorRendererX11Nested *x11_nested)
+{
+  MetaBackendX11 *backend = META_BACKEND_X11 (meta_get_backend ());
+  Window xwindow = meta_backend_x11_get_xwindow (backend);
+  Display *xdisplay = meta_backend_x11_get_xdisplay (backend);
+
+  Cursor empty_xcursor = create_empty_cursor (xdisplay);
+  XDefineCursor (xdisplay, xwindow, empty_xcursor);
+  XFreeCursor (xdisplay, empty_xcursor);
+}
+
+static void
+meta_cursor_renderer_x11_nested_class_init (MetaCursorRendererX11NestedClass *klass)
+{
+  MetaCursorRendererClass *renderer_class = META_CURSOR_RENDERER_CLASS (klass);
+
+  renderer_class->update_cursor = meta_cursor_renderer_x11_nested_update_cursor;
+}

src/backends/x11/nested/meta-cursor-renderer-x11-nested.h

@@ -0,0 +1,38 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2015 Red Hat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * Written by:
+ *     Jonas Ådahl <jadahl@gmail.com>
+ */
+
+#ifndef META_CURSOR_RENDERER_X11_NESTED_NESTED_H
+#define META_CURSOR_RENDERER_X11_NESTED_NESTED_H
+
+#include <glib-object.h>
+
+#include "backends/meta-cursor-renderer.h"
+
+#define META_TYPE_CURSOR_RENDERER_X11_NESTED (meta_cursor_renderer_x11_nested_get_type ())
+G_DECLARE_FINAL_TYPE (MetaCursorRendererX11Nested,
+                      meta_cursor_renderer_x11_nested,
+                      META, CURSOR_RENDERER_X11_NESTED,
+                      MetaCursorRenderer);
+
+#endif /* META_CURSOR_RENDERER_X11_NESTED_NESTED_H */