[gtk/subsurface-test] Add a quick subsurface test

[Matthias Clasen <matthiasc src gnome org>]

commit f367fe53ac3a5de71baea8a7aaf247634460f2a7
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu May 26 06:34:36 2022 -0400

    Add a quick subsurface test
    
    Add a subsurface to a GTK toplevel,
    and paint it green.

 tests/meson.build  |   1 +
 tests/subsurface.c | 147 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 148 insertions(+)
---
diff --git a/tests/meson.build b/tests/meson.build
index d837b5af6d..2466fa9656 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -1,5 +1,6 @@
 gtk_tests = [
   # testname, optional extra sources
+  ['subsurface'],
   ['input'],
   ['testpopup'],
   ['testupload'],
diff --git a/tests/subsurface.c b/tests/subsurface.c
new file mode 100644
index 0000000000..8daf0ee433
--- /dev/null
+++ b/tests/subsurface.c
@@ -0,0 +1,147 @@
+/* simple.c
+ * Copyright (C) 2017  Red Hat, Inc
+ * Author: Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "config.h"
+#include <gtk/gtk.h>
+#include <gdk/wayland/gdkwayland.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+static struct wl_compositor *wl_compositor;
+static struct wl_subcompositor *wl_subcompositor;
+static struct wl_shm *wl_shm;
+
+static void
+gdk_registry_handle_global (void               *data,
+                            struct wl_registry *registry,
+                            uint32_t            id,
+                            const char         *interface,
+                            uint32_t            version)
+{
+  //g_print ("global: %s %u, id %u\n", interface, version, id);
+  if (strcmp (interface, "wl_compositor") == 0)
+    wl_compositor = wl_registry_bind (registry, id, &wl_compositor_interface, version);
+
+  if (strcmp (interface, "wl_subcompositor") == 0)
+    wl_subcompositor = wl_registry_bind (registry, id, &wl_subcompositor_interface, version);
+
+  if (strcmp (interface, "wl_shm") == 0)
+    wl_shm = wl_registry_bind (registry, id, &wl_shm_interface, version);
+}
+
+static void
+gdk_registry_handle_global_remove (void               *data,
+                                   struct wl_registry *registry,
+                                   uint32_t            id)
+{
+}
+
+static const struct wl_registry_listener registry_listener = {
+    gdk_registry_handle_global,
+    gdk_registry_handle_global_remove
+};
+
+static void
+set_up_registry (struct wl_display *wl_display)
+{
+  struct wl_registry *wl_registry;
+
+  wl_registry = wl_display_get_registry (wl_display);
+  wl_registry_add_listener (wl_registry, &registry_listener, NULL);
+  if (wl_display_roundtrip (wl_display) < 0)
+    exit (1);
+
+  g_assert (wl_compositor != NULL);
+  g_assert (wl_subcompositor != NULL);
+  g_assert (wl_shm != NULL);
+}
+
+static void
+create_subsurface (struct wl_surface     *parent,
+                   struct wl_surface    **child,
+                   struct wl_subsurface **subsurface)
+{
+  *child = wl_compositor_create_surface (wl_compositor);
+  *subsurface = wl_subcompositor_get_subsurface (wl_subcompositor, *child, parent);
+  wl_subsurface_set_desync (*subsurface);
+}
+
+static void
+surface_fill (struct wl_surface *surface,
+              int                width,
+              int                height)
+{
+  size_t size;
+  const char *xdg_runtime_dir;
+  int fd;
+  guint32 *data;
+  struct wl_shm_pool *pool;
+  struct wl_buffer *buffer;
+
+  size = width * height * 4;
+  xdg_runtime_dir = getenv ("XDG_RUNTIME_DIR");
+  fd = open (xdg_runtime_dir, O_TMPFILE|O_RDWR|O_EXCL, 0600);
+  ftruncate (fd, size);
+  data = mmap (NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+
+  for (int i = 0; i < height; i++)
+    for (int j = 0; j < width; j++)
+      data[i * width + j] = 0xff00ff00;
+
+  pool = wl_shm_create_pool (wl_shm, fd, size);
+  buffer = wl_shm_pool_create_buffer (pool, 0, width, height, width * 4, WL_SHM_FORMAT_XRGB8888);
+  wl_shm_pool_destroy (pool);
+
+  close (fd);
+
+  wl_surface_attach (surface, buffer, 0, 0);
+  wl_surface_commit (surface);
+}
+
+int
+main (int argc, char *argv[])
+{
+  GtkWidget *window;
+  GdkSurface *surface;
+  struct wl_display *wl_display;
+  struct wl_surface *parent;
+  struct wl_surface *child;
+  struct wl_subsurface *subsurface;
+
+  gtk_init ();
+
+  window = gtk_window_new ();
+  gtk_window_set_title (GTK_WINDOW (window), "hello world");
+
+  gtk_widget_show (window);
+
+  surface = gtk_native_get_surface (GTK_NATIVE (window));
+
+  wl_display = gdk_wayland_display_get_wl_display (gdk_display_get_default ());
+  parent = gdk_wayland_surface_get_wl_surface (surface);
+
+  set_up_registry (wl_display);
+  create_subsurface (parent, &child, &subsurface);
+  wl_subsurface_set_position (subsurface, 100, 100);
+  surface_fill (child, 100, 100);
+
+  while (TRUE)
+    g_main_context_iteration (NULL, TRUE);
+
+  return 0;
+}