tools: Add more commands to gtk4-path-tool

Add pathops.

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

@@ -14,6 +14,11 @@ SYNOPSIS
 |
 |   **gtk4-path-tool** stroke [OPTIONS...] <PATH>
 |   **gtk4-path-tool** offset [OPTIONS...] <PATH>
+|   **gtk4-path-tool** simplify [OPTIONS...] <PATH>
+|   **gtk4-path-tool** intersection [OPTIONS...] <PATH> <PATH>
+|   **gtk4-path-tool** union [OPTIONS...] <PATH> <PATH>
+|   **gtk4-path-tool** difference [OPTIONS...] <PATH> <PATH>
+|   **gtk4-path-tool** symmetric-difference [OPTIONS...] <PATH> <PATH>
 |   **gtk4-path-tool** decompose [OPTIONS...] <PATH>
 |   **gtk4-path-tool** restrict [OPTIONS...] <PATH>
 |   **gtk4-path-tool** show [OPTIONS...] <PATH>
@@ -96,6 +101,21 @@ is different from applying a translation transformation.
 
   The limit at which to clip miters at line joins. The default value is 4.
 
+Boolean Operations
+^^^^^^^^^^^^^^^^^^
+
+The ``intersection``, ``union``, ``difference`` and ``symmetric-difference`` commands
+perform boolean operations on paths. Given two paths, they create a new path which
+encircles the area that is the intersection, union, difference or symmetric difference
+of the areas encircled by the paths.
+
+Simplification
+^^^^^^^^^^^^^^
+
+The ``simplify`` command removes areas of overlap from a path such that the resulting
+path encircles the same area, but every edge in the resulting path is a boundary between
+the inside and the outside.
+
 Decomposing
 ^^^^^^^^^^^
 

tools/gtk-path-tool-pathops.c

@@ -0,0 +1,104 @@
+/*  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.
+ *
+ * GLib 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 <gtk/gtk.h>
+#include "gtk-path-tool.h"
+
+#include <glib/gi18n-lib.h>
+
+void
+do_pathop (const char *op, int *argc, const char ***argv)
+{
+  GError *error = NULL;
+  const char *fill = "winding";
+  char **args = NULL;
+  GOptionContext *context;
+  GOptionEntry entries[] = {
+    { "fill-rule", 0, 0, G_OPTION_ARG_STRING, &fill, N_("Fill rule"), N_("RULE") },
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args, NULL, N_("PATH…") },
+    { NULL, },
+  };
+  GskPath *path1, *path2, *result;
+  GskFillRule fill_rule;
+  char *prgname;
+  char *summary;
+
+  prgname = g_strconcat ("gtk4-path-tool ", op, NULL);
+  summary = g_strdup_printf (_("Apply the %s path operation."), op);
+  g_set_prgname (prgname);
+
+  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, summary);
+
+  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 (args == NULL)
+    {
+      g_printerr ("%s\n", _("No paths given."));
+      exit (1);
+    }
+
+  path1 = get_path (args[0]);
+  if (args[1] != NULL)
+    path2 = get_path (args[1]);
+  else
+    path2 = NULL;
+
+  fill_rule = get_enum_value (GSK_TYPE_FILL_RULE, _("fill rule"), fill);
+
+  if (strcmp (op, "simplify") == 0)
+    result = gsk_path_simplify (path1, fill_rule);
+  else if (strcmp (op, "union") == 0)
+    result = gsk_path_union (path1, path2, fill_rule);
+  else if (strcmp (op, "intersection") == 0)
+    result = gsk_path_intersection (path1, path2, fill_rule);
+  else if (strcmp (op, "difference") == 0)
+    result = gsk_path_difference (path1, path2, fill_rule);
+  else if (strcmp (op, "symmetric-difference") == 0)
+    result = gsk_path_symmetric_difference (path1, path2, fill_rule);
+  else
+    {
+      char *msg = g_strdup_printf (_("'%s' is not a supported operation."), op);
+      g_printerr ("%s\n", msg);
+      exit (1);
+    }
+
+  if (result)
+    {
+      char *str = gsk_path_to_string (result);
+      g_print ("%s\n", str);
+      g_free (str);
+    }
+  else
+    {
+      g_printerr ("%s\n", _("That didn't work out."));
+      exit (1);
+    }
+}

tools/gtk-path-tool.c

@@ -40,6 +40,12 @@ usage (void)
              "Commands:\n"
              "  stroke       Stroke the path\n"
              "  offset       Offset the path\n"
+             "  simplify     Simplify the path\n"
+             "  intersection Intersect two paths\n"
+             "  union        Create the union of two paths\n"
+             "  difference   Create the difference of two paths\n"
+             "  symmetric-difference\n"
+             "               Create the symmetric difference of two paths\n"
              "  decompose    Decompose the path\n"
              "  restrict     Restrict the path to a segment\n"
              "  show         Display the path in a window\n"
@@ -129,8 +135,12 @@ main (int argc, const char *argv[])
 
   if (strcmp (argv[0], "decompose") == 0)
     do_decompose (&argc, &argv);
+  else if (strcmp (argv[0], "difference") == 0)
+    do_pathop (argv[0], &argc, &argv);
   else if (strcmp (argv[0], "info") == 0)
     do_info (&argc, &argv);
+  else if (strcmp (argv[0], "intersection") == 0)
+    do_pathop (argv[0], &argc, &argv);
   else if (strcmp (argv[0], "offset") == 0)
     do_offset (&argc, &argv);
   else if (strcmp (argv[0], "render") == 0)
@@ -139,8 +149,14 @@ main (int argc, const char *argv[])
     do_restrict (&argc, &argv);
   else if (strcmp (argv[0], "show") == 0)
     do_show (&argc, &argv);
+  else if (strcmp (argv[0], "simplify") == 0)
+    do_pathop (argv[0], &argc, &argv);
   else if (strcmp (argv[0], "stroke") == 0)
     do_stroke (&argc, &argv);
+  else if (strcmp (argv[0], "symmetric-difference") == 0)
+    do_pathop (argv[0], &argc, &argv);
+  else if (strcmp (argv[0], "union") == 0)
+    do_pathop (argv[0], &argc, &argv);
   else
     usage ();
 

tools/gtk-path-tool.h

@@ -7,6 +7,7 @@ void do_decompose (int *argc, const char ***argv);
 void do_restrict  (int *argc, const char ***argv);
 void do_render    (int *argc, const char ***argv);
 void do_show      (int *argc, const char ***argv);
+void do_pathop    (const char *op, int *argc, const char ***argv);
 
 GskPath *get_path       (const char *arg);
 int      get_enum_value (GType       type,

tools/meson.build

@@ -27,6 +27,7 @@ gtk_tools = [
                       'gtk-path-tool-decompose.c',
                       'gtk-path-tool-info.c',
                       'gtk-path-tool-offset.c',
+                      'gtk-path-tool-pathops.c',
                       'gtk-path-tool-render.c',
                       'gtk-path-tool-restrict.c',
                       'gtk-path-tool-show.c',