tools: Add more commands to gtk4-path-tool

Add pathops.

demos/gtk-demo/demo.gresource.xml

@@ -295,6 +295,7 @@
     <file>gears.c</file>
     <file>gestures.c</file>
     <file>glarea.c</file>
+    <file>glyphs.c</file>
     <file>gltransition.c</file>
     <file>headerbar.c</file>
     <file>hypertext.c</file>

demos/gtk-demo/meson.build

@@ -34,6 +34,7 @@ demos = files([
   'gestures.c',
   'glarea.c',
   'gltransition.c',
+  'glyphs.c',
   'headerbar.c',
   'hypertext.c',
   'iconscroll.c',

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

@@ -12,6 +12,11 @@ SYNOPSIS
 --------
 |   **gtk4-path-tool** <COMMAND> [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** show [OPTIONS...] <PATH>
 |   **gtk4-path-tool** render [OPTIONS...] <PATH>
@@ -195,6 +200,7 @@ The interior of the path is filled.
 
   The limit at which to clip miters at line joins. The default value is 4.
 
+<<<<<<< HEAD
 ``--dashes=VALUE``
 
   The dash pattern to use for this stroke. A dash pattern is specified by
@@ -208,6 +214,21 @@ The interior of the path is filled.
   The offset into the dash pattern where dashing should begin.
   The default value is 0.
 
+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.
+
 Reversing
 ^^^^^^^^^
 

gsk/gskpath.h

@@ -193,6 +193,30 @@ gboolean                gsk_path_foreach_intersection           (GskPath
                                                                  GskPathIntersectionFunc func,
                                                                  gpointer                user_data);
 
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_union                          (GskPath                *first,
+                                                                 GskPath                *second,
+                                                                 GskFillRule             fill_rule);
+
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_intersection                   (GskPath                *first,
+                                                                 GskPath                *second,
+                                                                 GskFillRule             fill_rule);
+
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_difference                     (GskPath                *first,
+                                                                 GskPath                *second,
+                                                                 GskFillRule             fill_rule);
+
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_symmetric_difference           (GskPath                *first,
+                                                                 GskPath                *second,
+                                                                 GskFillRule             fill_rule);
+
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_simplify                       (GskPath                *self,
+                                                                 GskFillRule             fill_rule);
+
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskPath, gsk_path_unref)
 
 G_END_DECLS

gsk/gskpathprivate.h

@@ -56,5 +56,19 @@ gboolean                gsk_path_foreach_with_tolerance         (GskPath
 void                    gsk_path_builder_add_contour            (GskPathBuilder         *builder,
                                                                  GskContour             *contour);
 
+typedef enum
+{
+  GSK_PATH_OP_SIMPLIFY,
+  GSK_PATH_OP_UNION,
+  GSK_PATH_OP_INTERSECTION,
+  GSK_PATH_OP_DIFFERENCE,
+  GSK_PATH_OP_XOR
+} GskPathOp;
+
+GskPath *               gsk_path_op                             (GskPathOp               operation,
+                                                                 GskFillRule             fill_rule,
+                                                                 GskPath                *first,
+                                                                 GskPath                *second);
+
 G_END_DECLS
 

gsk/meson.build

@@ -30,6 +30,7 @@ gsk_public_sources = files([
   'gskpathbuilder.c',
   'gskpathintersect.c',
   'gskpathmeasure.c',
+  'gskpathops.c',
   'gskpathparser.c',
   'gskpathpoint.c',
   'gskrenderer.c',

testsuite/gsk/meson.build

@@ -375,6 +375,7 @@ tests = [
   ['path', [ 'path-utils.c' ] ],
   ['path-special-cases'],
   ['path-intersect'],
+  ['path-ops', [ 'path-utils.c' ] ],
 ]
 
 test_cargs = []

testsuite/gsk/path-ops.c

@@ -0,0 +1,381 @@
+/*
+ * Copyright © 2022 Red Hat, Inc.
+ *
+ * This library 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 2.1 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Matthias Clasen <mclasen@redhat.com>
+ */
+
+#include <gtk/gtk.h>
+
+#include "path-utils.h"
+
+typedef enum
+{
+  OP_UNION,
+  OP_INTERSECTION,
+  OP_DIFFERENCE,
+  OP_SYMMETRIC_DIFFERENCE,
+} Op;
+
+static void
+test_ops_simple (void)
+{
+  struct {
+    const char *in1;
+    const char *in2;
+    Op op;
+    const char *out;
+  } tests[] = {
+    /* partially overlapping edge */
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 150 150 L 150 250 L 250 250 Z",
+      OP_UNION,
+      "M 100 100 L 100 200 L 150 200 L 150 250 L 250 250 L 200 200 L 150 150 L 100 100 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 150 150 L 150 250 L 250 250 Z",
+      OP_INTERSECTION,
+      "M 150 200 L 200 200 L 150 150 L 150 200 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 150 150 L 150 250 L 250 250 Z",
+      OP_DIFFERENCE,
+      "M 100 100 L 100 200 L 150 200 L 150 150 L 100 100 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 150 150 L 150 250 L 250 250 Z",
+      OP_SYMMETRIC_DIFFERENCE,
+      "M 100 100 L 100 200 L 150 200 L 150 150 L 100 100 Z M 200 200 L 150 200 L 150 250 "
+      "L 250 250 L 200 200 Z" },
+    /* two triangles in general position */
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 170 120 L 100 240 L 170 240 Z",
+      OP_UNION,
+      "M 100 100 L 100 200 L 123.33333587646484 200 L 100 240 L 170 240 L 170 200 L 200 200 "
+      "L 170 170 L 170 120 L 151.57894897460938 151.57894897460938 L 100 100 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 170 120 L 100 240 L 170 240 Z",
+      OP_INTERSECTION,
+      "M 123.33333587646484 200 L 170 200 L 170 170 L 151.57894897460938 151.57894897460938 "
+      "L 123.33332824707031 200 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 170 120 L 100 240 L 170 240 Z",
+      OP_DIFFERENCE,
+      "M 100 100 L 100 200 L 123.33333587646484 200 L 151.57894897460938 151.57894897460938 "
+      "L 100 100 Z M 170 200 L 200 200 L 170 170 L 170 200 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 170 120 L 100 240 L 170 240 Z",
+      OP_SYMMETRIC_DIFFERENCE,
+      "M 100 100 L 100 200 L 123.33333587646484 200 L 151.57894897460938 151.57894897460938 "
+      "L 100 100 Z M 170 200 L 123.33333587646484 200 L 100 240 L 170 240 L 170 200 Z "
+      "M 170 200 L 200 200 L 170 170 L 170 200 Z M 151.57894897460938 151.57894897460938 "
+      "L 170 170 L 170 120 L 151.57894897460938 151.57894897460938 Z" },
+    /* nested contours, oriented in opposite direction */
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 120 140 L 170 190 L 120 190 Z",
+      OP_UNION,
+      "M 100 100 L 100 200 L 200 200 L 100 100 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 120 140 L 170 190 L 120 190 Z",
+      OP_INTERSECTION,
+      "M 170 190 L 120 140 L 120 190 L 170 190 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 120 140 L 170 190 L 120 190 Z",
+      OP_DIFFERENCE,
+      "M 100 100 L 100 200 L 200 200 L 100 100 Z M 120 140 L 170 190 L 120 190 L 120 140 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 120 140 L 170 190 L 120 190 Z",
+      OP_SYMMETRIC_DIFFERENCE,
+      "M 100 100 L 100 200 L 200 200 L 100 100 Z M 120 140 L 170 190 L 120 190 L 120 140 Z" },
+    /* nested contours, oriented in opposite direction, other way around */
+    { "M 100 100 L 200 200 L 100 200 Z",
+      "M 120 140 L 120 190 L 170 190 Z",
+      OP_UNION,
+      "M 200 200 L 100 100 L 100 200 L 200 200 Z" },
+    { "M 100 100 L 200 200 L 100 200 Z",
+      "M 120 140 L 120 190 L 170 190 Z",
+      OP_INTERSECTION,
+      "M 120 140 L 120 190 L 170 190 L 120 140 Z" },
+    { "M 100 100 L 200 200 L 100 200 Z",
+      "M 120 140 L 120 190 L 170 190 Z",
+      OP_DIFFERENCE,
+      "M 200 200 L 100 100 L 100 200 L 200 200 Z M 120 190 L 120 140 L 170 190 L 120 190 Z" },
+    { "M 100 100 L 200 200 L 100 200 Z",
+      "M 120 140 L 120 190 L 170 190 Z",
+      OP_SYMMETRIC_DIFFERENCE,
+      "M 200 200 L 100 100 L 100 200 L 200 200 Z M 120 190 L 120 140 L 170 190 L 120 190 Z" },
+    /* nested contours, oriented in the same direction */
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 120 140 L 120 190 L 170 190 Z",
+      OP_UNION,
+      "M 100 100 L 100 200 L 200 200 L 100 100 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 120 140 L 120 190 L 170 190 Z",
+      OP_INTERSECTION,
+      "M 120 140 L 120 190 L 170 190 L 120 140 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 120 140 L 120 190 L 170 190 Z",
+      OP_DIFFERENCE,
+      "M 100 100 L 100 200 L 200 200 L 100 100 Z M 120 190 L 120 140 L 170 190 L 120 190 Z" },
+    { "M 100 100 L 100 200 L 200 200 Z",
+      "M 120 140 L 120 190 L 170 190 Z",
+      OP_SYMMETRIC_DIFFERENCE,
+      "M 100 100 L 100 200 L 200 200 L 100 100 Z M 120 190 L 120 140 L 170 190 L 120 190 Z" },
+    /* a 3-way intersection */
+    { "M 100 200 L 150 104 L 145 104 L 200 200 Z",
+      "M 100 108.571 L 200 108.571 L 200 50 L 100 50 Z",
+      OP_UNION,
+      "M 147.61904907226562 108.57142639160156 L 100 200 L 200 200 "
+      "L 147.61904907226562 108.57142639160156 Z M 100 108.57099914550781 "
+      "L 147.61927795410156 108.57099914550781 L 200 108.57099914550781 L 200 50 "
+      "L 100 50 L 100 108.57099914550781 Z" },
+    { "M 100 200 L 150 104 L 145 104 L 200 200 Z",
+      "M 100 108.571 L 200 108.571 L 200 50 L 100 50 Z",
+      OP_INTERSECTION,
+      "M 147.61904907226562 108.57142639160156 L 150 104 L 145 104 "
+      "L 147.61904907226562 108.57142639160156 Z" },
+    { "M 100 200 L 150 104 L 145 104 L 200 200 Z",
+      "M 100 108.571 L 200 108.571 L 200 50 L 100 50 Z",
+      OP_DIFFERENCE,
+      "M 147.61904907226562 108.57142639160156 L 100 200 L 200 200 "
+      "L 147.61904907226562 108.57142639160156 Z" },
+    { "M 100 200 L 150 104 L 145 104 L 200 200 Z",
+      "M 100 108.571 L 200 108.571 L 200 50 L 100 50 Z",
+      OP_SYMMETRIC_DIFFERENCE,
+      "M 147.61904907226562 108.57142639160156 L 100 200 L 200 200 "
+      "L 147.61904907226562 108.57142639160156 Z M 150 104 "
+      "L 147.61904907226562 108.57142639160156 L 200 108.57099914550781 "
+      "L 200 50 L 100 50 L 100 108.57099914550781 L 147.61927795410156 108.57099914550781 "
+      "L 145 104 L 150 104 Z" },
+     /* touching quadratics */
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 200 Q 150 100 200 200 Z",
+       OP_UNION,
+       "M 100 100 "
+       "Q 124.987984 149.975967, 149.975967 149.999985 "
+       "Q 174.987976 150.024033, 200 100 "
+       "L 100 100 "
+       "Z "
+       "M 149.975967 150 "
+       "Q 124.987984 150.024033, 100 200 "
+       "L 200 200 "
+       "Q 174.987976 149.975967, 149.975967 150.000015 "
+       "Z" },
+     /* overlapping quadratics, two intersections, different orientations */
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 180 Q 150 80 200 180 Z",
+       OP_UNION,
+       "M 100 100 "
+       "Q 113.819313 127.638626, 127.638626 139.999374 "
+       "Q 113.819695 152.360611, 100 180 "
+       "L 200 180 "
+       "Q 186.180313 152.360611, 172.360611 139.999939 "
+       "Q 186.180298 127.639389, 200 100 "
+       "L 100 100 "
+       "Z" },
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 180 Q 150 80 200 180 Z",
+       OP_INTERSECTION,
+       "M 127.638626 139.99939 "
+       "Q 149.999619 160.000275, 172.360611 140.000061 "
+       "Q 150 120.000061, 127.639389 139.999939 "
+       "Z" },
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 180 Q 150 80 200 180 Z",
+       OP_DIFFERENCE,
+       "M 100 100 "
+       "Q 113.819313 127.638626, 127.638626 139.999374 "
+       "Q 150 120.000061, 172.360611 139.999939 "
+       "Q 186.180298 127.639389, 200 100 "
+       "L 100 100 "
+       "Z" },
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 180 Q 150 80 200 180 Z",
+       OP_SYMMETRIC_DIFFERENCE,
+       "M 100 100 "
+       "Q 113.819313 127.638626, 127.638626 139.999374 "
+       "Q 150 120.000061, 172.360611 139.999939 "
+       "Q 186.180298 127.639389, 200 100 "
+       "L 100 100 "
+       "Z "
+       "M 172.360611 140.000061 "
+       "Q 149.999619 160.000275, 127.638626 139.999374 "
+       "Q 113.819695 152.360611, 100 180 "
+       "L 200 180 "
+       "Q 186.180313 152.360611, 172.360611 139.999939 "
+       "Z" },
+     /* overlapping quadratics, two intersections, same orientation */
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 180 L 200 180 Q 150 80 100 180 Z",
+       OP_UNION,
+       "M 100 100 "
+       "Q 113.819313 127.638626, 127.638626 139.999374 "
+       "Q 113.819695 152.360611, 100 180 "
+       "L 200 180 "
+       "Q 186.180695 152.361374, 172.361389 140.000626 "
+       "Q 186.180298 127.639389, 200 100 "
+       "L 100 100 "
+       "Z" },
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 180 L 200 180 Q 150 80 100 180 Z",
+       OP_INTERSECTION,
+       "M 127.638626 139.99939 "
+       "Q 149.999619 160.000275, 172.360611 140.000061 "
+       "Q 150.000397 119.999725, 127.639397 139.999939 "
+       "Z" },
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 180 L 200 180 Q 150 80 100 180 Z",
+       OP_DIFFERENCE,
+       "M 100 100 "
+       "Q 113.819313 127.638626, 127.638626 139.999374 "
+       "Q 150.000397 119.999725, 172.361389 140.000626 "
+       "Q 186.180298 127.639389, 200 100 "
+       "L 100 100 "
+       "Z" },
+     { "M 100 100 Q 150 200 200 100 Z",
+       "M 100 180 L 200 180 Q 150 80 100 180 Z",
+       OP_SYMMETRIC_DIFFERENCE,
+       "M 100 100 "
+       "Q 113.819313 127.638626, 127.638626 139.999374 "
+       "Q 150.000397 119.999725, 172.361389 140.000626 "
+       "Q 186.180298 127.639389, 200 100 "
+       "L 100 100 "
+       "Z "
+       "M 172.360611 140.000061 "
+       "Q 149.999619 160.000275, 127.638626 139.999374 "
+       "Q 113.819695 152.360611, 100 180 "
+       "L 200 180 "
+       "Q 186.180695 152.361374, 172.361389 140.000626 "
+       "Z" },
+     /* two polygons with near edges */
+     { "M 100 100 L 100 200 L 400 200 L 400 100 Z",
+       "M 150 103 L 250 100 L 300 103 L 250 180 Z",
+       OP_UNION,
+       "M 100 100 L 100 200 L 400 200 L 400 100 L 250 100 L 100 100 Z" },
+     { "M 100 100 L 100 200 L 400 200 L 400 100 Z",
+       "M 150 103 L 250 100 L 300 103 L 250 180 Z",
+       OP_INTERSECTION,
+      "M 250 100 L 150 103 L 250 180 L 300 103 L 250 100 Z" },
+     { "M 100 100 L 100 200 L 400 200 L 400 100 Z",
+       "M 150 103 L 250 100 L 300 103 L 250 180 Z",
+       OP_DIFFERENCE,
+       "M 100 100 L 100 200 L 400 200 L 400 100 L 250 100 L 300 103 L 250 180 L 150 103 L 250 100 L 100 100 Z" },
+     { "M 100 100 L 100 200 L 400 200 L 400 100 Z",
+       "M 150 103 L 250 100 L 300 103 L 250 180 Z",
+       OP_SYMMETRIC_DIFFERENCE,
+       "M 100 100 L 100 200 L 400 200 L 400 100 L 250 100 L 300 103 L 250 180 L 150 103 L 250 100 L 100 100 Z" },
+     /* Collinear line segments */
+     { "M 100 100 L 200 100 L 250 100 L 100 200 Z",
+       "M 150 100 L 300 100 L 300 200 Z",
+       OP_UNION,
+       "M 150 100 "
+       "L 100 100 "
+       "L 100 200 "
+       "L 200 133.333328 "
+       "L 300 200 "
+       "L 300 100 "
+       "L 250 100 "
+       "L 200 100 "
+       "L 150 100 "
+       "Z" },
+     { "M 100 100 L 200 100 L 250 100 L 100 200 Z",
+       "M 150 100 L 300 100 L 300 200 Z",
+       OP_INTERSECTION,
+       "M 200 100 "
+       "L 150 100 "
+       "L 200 133.333328 "
+       "L 250 100 "
+       "L 200 100 "
+       "Z" },
+     { "M 100 100 L 200 100 L 250 100 L 100 200 Z",
+       "M 150 100 L 300 100 L 300 200 Z",
+       OP_DIFFERENCE,
+       "M 150 100 L 100 100 L 100 200 L 200 133.33332824707031 L 150 100 Z" },
+     { "M 100 100 L 200 100 L 250 100 L 100 200 Z",
+       "M 150 100 L 300 100 L 300 200 Z",
+       OP_SYMMETRIC_DIFFERENCE,
+       "M 150 100 L 100 100 L 100 200 L 200 133.33332824707031 L 150 100 Z "
+       "M 250 100 L 200 133.33332824707031 L 300 200 L 300 100 L 250 100 Z" },
+     /* a complicated union */
+     { "M 175 100 L 175 400 L 300 400 L 300 100 z",
+       "M 100 100 C 200 200 200 300 100 400 L 0 400 C 233.3333334 300 233.3333334 200 0 100 Z",
+       OP_UNION,
+       "M 175 100 "
+       "L 175 250 "
+       "L 175 400 "
+       "L 300 400 "
+       "L 300 100 "
+       "L 175 100 "
+       "Z "
+       "M 175 250 "
+       "Q 175 175, 100 100 "
+       "L 0 100 "
+       "Q 174.955811 174.981064, 174.999985 249.962112 "
+       "Z "
+       "M 100 400 "
+       "Q 175 325, 175 250 "
+       "Q 175.044189 324.981049, 0 400 "
+       "L 100 400 "
+       "Z" },
+ };
+
+  for (int i = 0; i < G_N_ELEMENTS (tests); i++)
+    {
+      GskPath *p1, *p2, *p3, *p;
+
+      if (g_test_verbose ())
+        {
+          const char *opname[] = { "union", "intersection", "difference", "symmetric-difference" };
+          g_test_message ("testcase %d op %s \"%s\" \"%s\"", i, opname[tests[i].op], tests[i].in1, tests[i].in2);
+        }
+
+      p1 = gsk_path_parse (tests[i].in1);
+      p2 = gsk_path_parse (tests[i].in2);
+      switch (tests[i].op)
+        {
+        case OP_UNION:
+          p = gsk_path_union (p1, p2, GSK_FILL_RULE_WINDING);
+          break;
+        case OP_INTERSECTION:
+          p = gsk_path_intersection (p1, p2, GSK_FILL_RULE_WINDING);
+          break;
+        case OP_DIFFERENCE:
+          p = gsk_path_difference (p1, p2, GSK_FILL_RULE_WINDING);
+          break;
+        case OP_SYMMETRIC_DIFFERENCE:
+          p = gsk_path_symmetric_difference (p1, p2, GSK_FILL_RULE_WINDING);
+          break;
+        default:
+          g_assert_not_reached ();
+        }
+
+      g_assert_nonnull (p);
+      p3 = gsk_path_parse (tests[i].out);
+      assert_path_equal_with_epsilon (p, p3, 0.0001);
+
+      gsk_path_unref (p);
+      gsk_path_unref (p1);
+      gsk_path_unref (p2);
+      gsk_path_unref (p3);
+    }
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  gtk_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/ops/simple", test_ops_simple);
+
+  return g_test_run ();
+}

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

@@ -38,6 +38,12 @@ usage (void)
              "Perform various tasks on paths.\n"
              "\n"
              "Commands:\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"
              "  reverse      Reverse the path\n"
              "  restrict     Restrict the path to a segment\n"
@@ -128,8 +134,12 @@ 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], "render") == 0)
     do_render (&argc, &argv);
   else if (strcmp (argv[0], "restrict") == 0)
@@ -138,6 +148,12 @@ main (int argc, const char *argv[])
     do_reverse (&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], "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

@@ -6,6 +6,7 @@ void do_restrict  (int *argc, const char ***argv);
 void do_reverse   (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

@@ -26,6 +26,7 @@ gtk_tools = [
   ['gtk4-path-tool', ['gtk-path-tool.c',
                       'gtk-path-tool-decompose.c',
                       'gtk-path-tool-info.c',
+                      'gtk-path-tool-pathops.c',
                       'gtk-path-tool-render.c',
                       'gtk-path-tool-restrict.c',
                       'gtk-path-tool-reverse.c',