Add a gtk4-rendernode-tool

This is meant to work with serialized render nodes.

docs/reference/gtk/gtk4-rendernode-tool.rst

@@ -0,0 +1,51 @@
+.. _gtk4-rendernode-tool(1):
+
+====================
+gtk4-rendernode-tool
+====================
+
+-----------------------
+GskRenderNode Utility
+-----------------------
+
+SYNOPSIS
+--------
+|   **gtk4-rendernode-tool** <COMMAND> [OPTIONS...] <FILE>
+|
+|   **gtk4-rendernode-tool** info [OPTIONS...] <FILE>
+|   **gtk4-rendernode-tool** show [OPTIONS...] <FILE>
+|   **gtk4-rendernode-tool** render [OPTIONS...] <FILE>
+
+DESCRIPTION
+-----------
+
+``gtk4-rendernode-tool`` can perform various operations on serialized rendernodes.
+
+COMMANDS
+--------
+
+Information
+^^^^^^^^^^^
+
+The ``info`` command shows general information about the rendernode, such
+as the number of nodes, and the depth of the tree.
+
+Showing
+^^^^^^^
+
+The ``show`` command displays the rendernode.
+
+Rendering
+^^^^^^^^^
+
+The ``render`` command saves a rendering of the rendernode as a png image.
+The name of the file to write can be specified as a second FILE argument.
+
+``--renderer=RENDERER``
+
+  Use the given renderer. This option accepts the same values as the
+  ``GSK_RENDERER`` environment variable.
+
+``--force``
+
+  Overwrite an existing file.

docs/reference/gtk/meson.build

@@ -75,6 +75,7 @@ if get_option('man-pages') and rst2man.found()
     [ 'gtk4-encode-symbolic-svg', '1', ],
     [ 'gtk4-launch', '1', ],
     [ 'gtk4-query-settings', '1', ],
+    [ 'gtk4-rendernode-tool', '1' ],
     [ 'gtk4-update-icon-cache', '1', ],
   ]
 

po/POTFILES.in

@@ -425,4 +425,9 @@ tools/gtk-builder-tool-screenshot.c
 tools/gtk-builder-tool-simplify.c
 tools/gtk-builder-tool-validate.c
 tools/gtk-launch.c
+tools/gtk-rendernode-tool.c
+tools/gtk-rendernode-tool-info.c
+tools/gtk-rendernode-tool-show.c
+tools/gtk-rendernode-tool-render.c
+tools/gtk-rendernode-tool-utils.c
 tools/updateiconcache.c

tools/gtk-rendernode-tool-info.c

@@ -0,0 +1,235 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * GTK+ 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <glib/gi18n-lib.h>
+#include <glib/gprintf.h>
+#include <glib/gstdio.h>
+#include <gtk/gtk.h>
+#include "gtk-rendernode-tool.h"
+
+static void
+count_nodes (GskRenderNode *node,
+             unsigned int  *counts,
+             unsigned int  *depth)
+{
+  unsigned int d, dd;
+
+  counts[gsk_render_node_get_node_type (node)] += 1;
+  d = 0;
+
+  switch (gsk_render_node_get_node_type (node))
+    {
+    case GSK_CONTAINER_NODE:
+      for (unsigned int i = 0; i < gsk_container_node_get_n_children (node); i++)
+        {
+          count_nodes (gsk_container_node_get_child (node, i), counts, &dd);
+          d = MAX (d, dd);
+        }
+      break;
+
+    case GSK_CAIRO_NODE:
+    case GSK_COLOR_NODE:
+    case GSK_LINEAR_GRADIENT_NODE:
+    case GSK_REPEATING_LINEAR_GRADIENT_NODE:
+    case GSK_RADIAL_GRADIENT_NODE:
+    case GSK_REPEATING_RADIAL_GRADIENT_NODE:
+    case GSK_CONIC_GRADIENT_NODE:
+    case GSK_BORDER_NODE:
+    case GSK_TEXTURE_NODE:
+    case GSK_INSET_SHADOW_NODE:
+    case GSK_OUTSET_SHADOW_NODE:
+      break;
+
+    case GSK_TRANSFORM_NODE:
+      count_nodes (gsk_transform_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_OPACITY_NODE:
+      count_nodes (gsk_opacity_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_COLOR_MATRIX_NODE:
+      count_nodes (gsk_color_matrix_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_REPEAT_NODE:
+      count_nodes (gsk_repeat_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_CLIP_NODE:
+      count_nodes (gsk_clip_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_ROUNDED_CLIP_NODE:
+      count_nodes (gsk_rounded_clip_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_SHADOW_NODE:
+      count_nodes (gsk_shadow_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_BLEND_NODE:
+      count_nodes (gsk_blend_node_get_bottom_child (node), counts, &d);
+      count_nodes (gsk_blend_node_get_top_child (node), counts, &dd);
+      d = MAX (d, dd);
+      break;
+
+    case GSK_CROSS_FADE_NODE:
+      count_nodes (gsk_cross_fade_node_get_start_child (node), counts, &d);
+      count_nodes (gsk_cross_fade_node_get_end_child (node), counts, &dd);
+      d = MAX (d, dd);
+      break;
+
+    case GSK_TEXT_NODE:
+      break;
+
+    case GSK_BLUR_NODE:
+      count_nodes (gsk_blur_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_DEBUG_NODE:
+      count_nodes (gsk_debug_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_GL_SHADER_NODE:
+      for (unsigned int i = 0; i < gsk_gl_shader_node_get_n_children (node); i++)
+        {
+          count_nodes (gsk_gl_shader_node_get_child (node, i), counts, &dd);
+          d = MAX (d, dd);
+        }
+      break;
+
+    case GSK_TEXTURE_SCALE_NODE:
+      break;
+
+    case GSK_MASK_NODE:
+      count_nodes (gsk_mask_node_get_source (node), counts, &d);
+      count_nodes (gsk_mask_node_get_mask (node), counts, &dd);
+      d = MAX (d, dd);
+      break;
+
+    case GSK_NOT_A_RENDER_NODE:
+    default:
+      g_assert_not_reached ();
+    }
+
+  *depth = d + 1;
+}
+
+static const char *
+get_node_name (GskRenderNodeType type)
+{
+  GEnumClass *class;
+  GEnumValue *value;
+  const char *name;
+
+  class = g_type_class_ref (GSK_TYPE_RENDER_NODE_TYPE);
+  value = g_enum_get_value (class, type);
+  name = value->value_nick;
+  g_type_class_unref (class);
+
+  return name;
+}
+
+static void
+file_info (const char *filename)
+{
+  GskRenderNode *node;
+  unsigned int counts[GSK_MASK_NODE + 1] = { 0, };
+  unsigned int total = 0;
+  unsigned int namelen = 0;
+  unsigned int depth = 0;
+  graphene_rect_t bounds;
+
+  node = load_node_file (filename);
+
+  count_nodes (node, counts, &depth);
+
+  for (unsigned int i = 0; i < G_N_ELEMENTS (counts); i++)
+    {
+      total += counts[i];
+      if (counts[i] > 0)
+        namelen = MAX (namelen, strlen (get_node_name (i)));
+    }
+
+  g_print (_("Number of nodes: %u\n"), total);
+  for (unsigned int i = 0; i < G_N_ELEMENTS (counts); i++)
+    {
+      if (counts[i] > 0)
+        g_print ("  %*s: %u\n", namelen, get_node_name (i), counts[i]);
+    }
+
+  g_print (_("Depth: %u\n"), depth);
+
+  gsk_render_node_get_bounds (node, &bounds);
+  g_print (_("Bounds: %g x %g\n"), bounds.size.width, bounds.size.height);
+  g_print (_("Origin: %g %g\n"), bounds.origin.x, bounds.origin.y);
+
+  gsk_render_node_unref (node);
+}
+
+void
+do_info (int          *argc,
+         const char ***argv)
+{
+  GOptionContext *context;
+  char **filenames = NULL;
+  const GOptionEntry entries[] = {
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &filenames, NULL, N_("FILE") },
+    { NULL, }
+  };
+  GError *error = NULL;
+
+  g_set_prgname ("gtk4-rendernode-tool info");
+  context = g_option_context_new (NULL);
+  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
+  g_option_context_add_main_entries (context, entries, NULL);
+  g_option_context_set_summary (context, _("Provide information about the render node."));
+
+  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
+    {
+      g_printerr ("%s\n", error->message);
+      g_error_free (error);
+      exit (1);
+    }
+
+  g_option_context_free (context);
+
+  if (filenames == NULL)
+    {
+      g_printerr (_("No .node file specified\n"));
+      exit (1);
+    }
+
+  if (g_strv_length (filenames) > 1)
+    {
+      g_printerr (_("Can only accept a single .node file\n"));
+      exit (1);
+    }
+
+  file_info (filenames[0]);
+
+  g_strfreev (filenames);
+}

tools/gtk-rendernode-tool-render.c

@@ -0,0 +1,165 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * GTK+ 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <glib/gi18n-lib.h>
+#include <glib/gprintf.h>
+#include <glib/gstdio.h>
+#include <gtk/gtk.h>
+#include "gtk-rendernode-tool.h"
+
+static char *
+get_save_filename (const char *filename)
+{
+  int length = strlen (filename);
+  const char *extension = ".png";
+  char *result;
+
+  if (strcmp (filename + (length - strlen (".node")), ".node") == 0)
+    {
+      char *basename = g_strndup (filename, length - strlen (".node"));
+      result = g_strconcat (basename, extension, NULL);
+      g_free (basename);
+    }
+  else
+    result = g_strconcat (filename, extension, NULL);
+
+  return result;
+}
+
+static void
+render_file (const char *filename,
+             const char *renderer_name,
+             const char *save_file,
+             gboolean    force)
+{
+  GskRenderNode *node;
+  GBytes *bytes;
+  GdkTexture *texture;
+  char *save_to;
+  GskRenderer *renderer;
+  GdkSurface *window;
+  GError *error = NULL;
+
+  node = load_node_file (filename);
+
+  if (renderer_name)
+    g_object_set_data_full (G_OBJECT (gdk_display_get_default ()), "gsk-renderer",
+                            g_strdup (renderer_name), g_free);
+
+  window = gdk_surface_new_toplevel (gdk_display_get_default ());
+  renderer = gsk_renderer_new_for_surface (window);
+
+  texture = gsk_renderer_render_texture (renderer, node, NULL);
+
+  save_to = (char *)save_file;
+
+  if (save_to == NULL)
+    save_to = get_save_filename (filename);
+
+  if (g_file_test (save_to, G_FILE_TEST_EXISTS) && !force)
+    {
+      g_printerr (_("File %s exists.\n"
+                    "Use --force to overwrite.\n"), save_to);
+      exit (1);
+    }
+
+  bytes = gdk_texture_save_to_png_bytes (texture);
+
+  if (g_file_set_contents (save_to,
+                           g_bytes_get_data (bytes, NULL),
+                           g_bytes_get_size (bytes),
+                           &error))
+    {
+      if (save_file == NULL)
+        g_print (_("Output written to %s.\n"), save_to);
+    }
+  else
+    {
+      g_printerr (_("Failed to save %s: %s\n"), save_to, error->message);
+      exit (1);
+    }
+
+  g_bytes_unref (bytes);
+
+  if (save_to != save_file)
+    g_free (save_to);
+
+  g_object_unref (texture);
+  gsk_render_node_unref (node);
+}
+
+void
+do_render (int          *argc,
+           const char ***argv)
+{
+  GOptionContext *context;
+  char **filenames = NULL;
+  gboolean force = FALSE;
+  char *renderer = NULL;
+  const GOptionEntry entries[] = {
+    { "renderer", 0, 0, G_OPTION_ARG_STRING, &renderer, N_("Renderer to use"), N_("RENDERER") },
+    { "force", 0, 0, G_OPTION_ARG_NONE, &force, N_("Overwrite existing file"), NULL },
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &filenames, NULL, N_("FILE…") },
+    { NULL, }
+  };
+  GError *error = NULL;
+
+  if (gdk_display_get_default () == NULL)
+    {
+      g_printerr (_("Could not initialize windowing system\n"));
+      exit (1);
+    }
+
+  g_set_prgname ("gtk4-rendernode-tool render");
+  context = g_option_context_new (NULL);
+  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
+  g_option_context_add_main_entries (context, entries, NULL);
+  g_option_context_set_summary (context, _("Render a .node file to an image."));
+
+  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
+    {
+      g_printerr ("%s\n", error->message);
+      g_error_free (error);
+      exit (1);
+    }
+
+  g_option_context_free (context);
+
+  if (filenames == NULL)
+    {
+      g_printerr (_("No .node file specified\n"));
+      exit (1);
+    }
+
+  if (g_strv_length (filenames) > 2)
+    {
+      g_printerr (_("Can only render a single .node file to a single output file\n"));
+      exit (1);
+    }
+
+  render_file (filenames[0], renderer, filenames[1], force);
+
+  g_strfreev (filenames);
+}

tools/gtk-rendernode-tool-show.c

@@ -0,0 +1,143 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * GTK+ 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <glib/gi18n-lib.h>
+#include <glib/gprintf.h>
+#include <glib/gstdio.h>
+#include <gtk/gtk.h>
+#include "gtk-rendernode-tool.h"
+
+
+static void
+set_window_title (GtkWindow  *window,
+                  const char *filename)
+{
+  char *name;
+
+  name = g_path_get_basename (filename);
+  gtk_window_set_title (window, name);
+  g_free (name);
+}
+
+static void
+quit_cb (GtkWidget *widget,
+         gpointer   user_data)
+{
+  gboolean *is_done = user_data;
+
+  *is_done = TRUE;
+
+  g_main_context_wakeup (NULL);
+}
+
+static void
+show_file (const char *filename)
+{
+  GskRenderNode *node;
+  GdkPaintable *paintable;
+  GtkWidget *sw;
+  GtkWidget *window;
+  gboolean done = FALSE;
+  GtkSnapshot *snapshot;
+  GtkWidget *picture;
+
+  node = load_node_file (filename);
+
+  snapshot = gtk_snapshot_new ();
+  gtk_snapshot_append_node (snapshot, node);
+  paintable = gtk_snapshot_free_to_paintable (snapshot, NULL);
+
+  picture = gtk_picture_new_for_paintable (paintable);
+  gtk_picture_set_can_shrink (GTK_PICTURE (picture), FALSE);
+  gtk_picture_set_content_fit (GTK_PICTURE (picture), GTK_CONTENT_FIT_SCALE_DOWN);
+
+  sw = gtk_scrolled_window_new ();
+  gtk_scrolled_window_set_propagate_natural_width (GTK_SCROLLED_WINDOW (sw), TRUE);
+  gtk_scrolled_window_set_propagate_natural_height (GTK_SCROLLED_WINDOW (sw), TRUE);
+  gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), picture);
+
+  window = gtk_window_new ();
+  set_window_title (GTK_WINDOW (window), filename);
+  gtk_window_set_child (GTK_WINDOW (window), sw);
+
+  gtk_window_present (GTK_WINDOW (window));
+  g_signal_connect (window, "destroy", G_CALLBACK (quit_cb), &done);
+
+  while (!done)
+    g_main_context_iteration (NULL, TRUE);
+
+  g_clear_object (&paintable);
+  g_clear_pointer (&node, gsk_render_node_unref);
+}
+
+void
+do_show (int          *argc,
+         const char ***argv)
+{
+  GOptionContext *context;
+  char **filenames = NULL;
+  const GOptionEntry entries[] = {
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &filenames, NULL, N_("FILE") },
+    { NULL, }
+  };
+  GError *error = NULL;
+
+  if (gdk_display_get_default () == NULL)
+    {
+      g_printerr (_("Could not initialize windowing system\n"));
+      exit (1);
+    }
+
+  g_set_prgname ("gtk4-rendernode-tool show");
+  context = g_option_context_new (NULL);
+  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
+  g_option_context_add_main_entries (context, entries, NULL);
+  g_option_context_set_summary (context, _("Show the render node."));
+
+  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
+    {
+      g_printerr ("%s\n", error->message);
+      g_error_free (error);
+      exit (1);
+    }
+
+  g_option_context_free (context);
+
+  if (filenames == NULL)
+    {
+      g_printerr (_("No .node file specified\n"));
+      exit (1);
+    }
+
+  if (g_strv_length (filenames) > 1)
+    {
+      g_printerr (_("Can only preview a single .node file\n"));
+      exit (1);
+    }
+
+  show_file (filenames[0]);
+
+  g_strfreev (filenames);
+}

tools/gtk-rendernode-tool-utils.c

@@ -0,0 +1,77 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * GTK+ 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <glib/gi18n-lib.h>
+#include <glib/gprintf.h>
+#include <glib/gstdio.h>
+#include <gtk/gtk.h>
+#include "gtk-rendernode-tool.h"
+
+
+static void
+deserialize_error_func (const GskParseLocation *start,
+                        const GskParseLocation *end,
+                        const GError           *error,
+                        gpointer                user_data)
+{
+  GString *string = g_string_new ("<data>");
+
+  g_string_append_printf (string, ":%zu:%zu",
+                          start->lines + 1, start->line_chars + 1);
+  if (start->lines != end->lines || start->line_chars != end->line_chars)
+    {
+      g_string_append (string, "-");
+      if (start->lines != end->lines)
+        g_string_append_printf (string, "%zu:", end->lines + 1);
+      g_string_append_printf (string, "%zu", end->line_chars + 1);
+    }
+
+  g_printerr (_("Error at %s: %s\n"), string->str, error->message);
+
+  g_string_free (string, TRUE);
+}
+
+GskRenderNode *
+load_node_file (const char *filename)
+{
+  GFile *file;
+  GBytes *bytes;
+  GError *error = NULL;
+
+  file = g_file_new_for_commandline_arg (filename);
+  bytes = g_file_load_bytes (file, NULL, NULL, NULL);
+  g_object_unref (file);
+
+  if (bytes == NULL)
+    return NULL;
+
+  if (!g_utf8_validate (g_bytes_get_data (bytes, NULL), g_bytes_get_size (bytes), NULL))
+    {
+      g_bytes_unref (bytes);
+      return NULL;
+    }
+
+  return gsk_render_node_deserialize (bytes, deserialize_error_func, &error);
+}

tools/gtk-rendernode-tool.c

@@ -0,0 +1,120 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * GTK+ 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <glib/gi18n-lib.h>
+#include <glib/gprintf.h>
+#include <glib/gstdio.h>
+#include <gtk/gtk.h>
+#include "gtk-rendernode-tool.h"
+
+static void G_GNUC_NORETURN
+usage (void)
+{
+  g_print (_("Usage:\n"
+             "  gtk4-rendernode-tool [COMMAND] [OPTION…] FILE\n"
+             "\n"
+             "Perform various tasks on GTK render nodes.\n"
+             "\n"
+             "Commands:\n"
+             "  info         Provide information about the node\n"
+             "  show         Show the node\n"
+             "  render       Take a screenshot of the node\n"
+             "\n"));
+  exit (1);
+}
+
+static GLogWriterOutput
+log_writer_func (GLogLevelFlags   level,
+                 const GLogField *fields,
+                 gsize            n_fields,
+                 gpointer         user_data)
+{
+  gsize i;
+  const char *domain = NULL;
+  const char *message = NULL;
+
+  for (i = 0; i < n_fields; i++)
+    {
+      if (g_strcmp0 (fields[i].key, "GLIB_DOMAIN") == 0)
+        domain = fields[i].value;
+      else if (g_strcmp0 (fields[i].key, "MESSAGE") == 0)
+        message = fields[i].value;
+    }
+
+  if (message != NULL && !g_log_writer_default_would_drop (level, domain))
+    {
+      const char *prefix;
+      switch (level & G_LOG_LEVEL_MASK)
+        {
+        case G_LOG_LEVEL_ERROR:
+          prefix = "ERROR";
+          break;
+        case G_LOG_LEVEL_CRITICAL:
+          prefix = "CRITICAL";
+          break;
+        case G_LOG_LEVEL_WARNING:
+          prefix = "WARNING";
+          break;
+        default:
+          prefix = "INFO";
+          break;
+        }
+      g_printerr ("%s-%s: %s\n", domain, prefix, message);
+    }
+
+  return G_LOG_WRITER_HANDLED;
+}
+
+int
+main (int argc, const char *argv[])
+{
+  g_set_prgname ("gtk-rendernode-tool");
+
+  g_log_set_writer_func (log_writer_func, NULL, NULL);
+
+  gtk_init_check ();
+
+  gtk_test_register_all_types ();
+
+  if (argc < 2)
+    usage ();
+
+  if (strcmp (argv[1], "--help") == 0)
+    usage ();
+
+  argv++;
+  argc--;
+
+  if (strcmp (argv[0], "show") == 0)
+    do_show (&argc, &argv);
+  else if (strcmp (argv[0], "render") == 0)
+    do_render (&argc, &argv);
+  else if (strcmp (argv[0], "info") == 0)
+    do_info (&argc, &argv);
+  else
+    usage ();
+
+  return 0;
+}

tools/gtk-rendernode-tool.h

@@ -0,0 +1,8 @@
+
+#pragma once
+
+void do_show    (int *argc, const char ***argv);
+void do_render  (int *argc, const char ***argv);
+void do_info    (int *argc, const char ***argv);
+
+GskRenderNode *load_node_file (const char *filename);

tools/meson.build

@@ -31,6 +31,11 @@ gtk_tools = [
                          'gtk-builder-tool-screenshot.c',
                          'gtk-builder-tool-preview.c',
                          'fake-scope.c'], [libgtk_dep] ],
+  ['gtk4-rendernode-tool', ['gtk-rendernode-tool.c',
+                        'gtk-rendernode-tool-info.c',
+                        'gtk-rendernode-tool-render.c',
+                        'gtk-rendernode-tool-show.c',
+                        'gtk-rendernode-tool-utils.c'], [libgtk_dep] ],
   ['gtk4-update-icon-cache', ['updateiconcache.c', '../gtk/gtkiconcachevalidator.c' ] + extra_update_icon_cache_objs, [ libgtk_dep ] ],
   ['gtk4-encode-symbolic-svg', ['encodesymbolic.c'], [ libgtk_static_dep ] ],
 ]