wayland: Add single pixel buffer support

The "single pixel buffer" Wayland protocol extension provides a way for
clients to create 1x1 buffers with a single color, specified by
providing the color channels (red, green and blue) as well as the
alpha channel as a 32 bit unsigned integer.

For now, this is turned into a 1x1 texture. Future potential
improvements is to hook things up to the scanout candidate logic and
turn it into a scanout capable DMA buffer.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2246>

src/wayland/meta-wayland-single-pixel-buffer.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2022 Red Hat Inc.
+ *
+ * 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.
+ *
+ */
+
+#ifndef META_WAYLAND_SINGLE_PIXEL_BUFFER_H
+#define META_WAYLAND_SINGLE_PIXEL_BUFFER_H
+
+#include <glib.h>
+
+#include "cogl/cogl.h"
+#include "wayland/meta-wayland-types.h"
+
+typedef struct _MetaWaylandSinglePixelBuffer MetaWaylandSinglePixelBuffer;
+
+gboolean meta_wayland_single_pixel_buffer_attach (MetaWaylandBuffer  *buffer,
+                                                  CoglTexture       **texture,
+                                                  GError            **error);
+
+MetaWaylandSinglePixelBuffer * meta_wayland_single_pixel_buffer_from_buffer (MetaWaylandBuffer *buffer);
+
+void meta_wayland_init_single_pixel_buffer_manager (MetaWaylandCompositor *compositor);
+
+void meta_wayland_single_pixel_buffer_free (MetaWaylandSinglePixelBuffer *single_pixel_buffer);
+
+#endif /* META_WAYLAND_SINGLE_PIXEL_BUFFER_H */