From c9ca83443542710d247b5a4d67fa4bee2f73b31f Mon Sep 17 00:00:00 2001
From: Nicola Fontana <ntd@entidi.it>
Date: Wed, 16 Jan 2019 16:46:14 +0100
Subject: [PATCH] cpml: add and test cpml_angle_distance

---
 src/cpml/cpml-utils.c       | 19 ++++++++++++++
 src/cpml/cpml-utils.h       |  2 ++
 src/cpml/tests/.gitignore   |  1 +
 src/cpml/tests/Makefile.am  |  3 +++
 src/cpml/tests/test-utils.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 88 insertions(+)
 create mode 100644 src/cpml/tests/test-utils.c

diff --git a/src/cpml/cpml-utils.c b/src/cpml/cpml-utils.c
index 9e4db360..a99d0e46 100644
--- a/src/cpml/cpml-utils.c
+++ b/src/cpml/cpml-utils.c
@@ -57,3 +57,22 @@ cpml_angle(double angle)
 
     return angle;
 }
+
+/**
+ * cpml_angle_distance:
+ * @angle: first angle in radians
+ * @from: second angle in radians
+ *
+ * Computes the distance between the two given angles. The returned
+ * distance is always positive and is never greater than M_PI.
+ *
+ * Returns: the distance in radians
+ *
+ * Since: 1.0
+ **/
+double
+cpml_angle_distance(double angle, double from)
+{
+    double delta = cpml_angle(from - angle);
+    return fabs(delta);
+}
diff --git a/src/cpml/cpml-utils.h b/src/cpml/cpml-utils.h
index aada3c2a..3eaa94ed 100644
--- a/src/cpml/cpml-utils.h
+++ b/src/cpml/cpml-utils.h
@@ -34,6 +34,8 @@
 CAIRO_BEGIN_DECLS
 
 double          cpml_angle              (double         angle);
+double          cpml_angle_distance     (double         angle,
+                                         double         from);
 
 CAIRO_END_DECLS
 
diff --git a/src/cpml/tests/.gitignore b/src/cpml/tests/.gitignore
index 8101c527..28851b97 100644
--- a/src/cpml/tests/.gitignore
+++ b/src/cpml/tests/.gitignore
@@ -5,3 +5,4 @@
 /test-pair
 /test-primitive
 /test-segment
+/test-utils
diff --git a/src/cpml/tests/Makefile.am b/src/cpml/tests/Makefile.am
index 204834d6..7f978b24 100644
--- a/src/cpml/tests/Makefile.am
+++ b/src/cpml/tests/Makefile.am
@@ -10,6 +10,9 @@ LDADD=				$(top_builddir)/src/tests/libadgtest.la \
 				$(ADG_LIBS)
 
 
+TEST_PROGS+=			test-utils$(EXEEXT)
+test_utils_SOURCES=		test-utils.c
+
 TEST_PROGS+=			test-pair$(EXEEXT)
 test_pair_SOURCES=		test-pair.c
 
diff --git a/src/cpml/tests/test-utils.c b/src/cpml/tests/test-utils.c
new file mode 100644
index 00000000..9001c36e
--- /dev/null
+++ b/src/cpml/tests/test-utils.c
@@ -0,0 +1,63 @@
+/* ADG - Automatic Drawing Generation
+ * Copyright (C) 2007-2019  Nicola Fontana <ntd at entidi.it>
+ *
+ * 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 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, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA  02110-1301, USA.
+ */
+
+
+#include <adg-test.h>
+#include <cpml.h>
+#include <math.h>
+
+
+static void
+_cpml_behavior_angle(void)
+{
+    adg_assert_isapprox(0, cpml_angle(0));
+    adg_assert_isapprox(0, cpml_angle(2 * M_PI));
+    adg_assert_isapprox(M_PI, cpml_angle(M_PI));
+    adg_assert_isapprox(M_PI, cpml_angle(3 * M_PI));
+    adg_assert_isapprox(M_PI, cpml_angle(-M_PI));
+    adg_assert_isapprox(M_PI, cpml_angle(-3 * M_PI));
+    adg_assert_isapprox(-M_PI + 1, cpml_angle(-3 * M_PI + 1));
+}
+
+static void
+_cpml_behavior_angle_distance(void)
+{
+    adg_assert_isapprox(0, cpml_angle_distance(0, 0));
+    adg_assert_isapprox(0, cpml_angle_distance(M_PI, M_PI));
+    adg_assert_isapprox(0, cpml_angle_distance(M_PI, 3 * M_PI));
+    adg_assert_isapprox(0, cpml_angle_distance(M_PI, -M_PI));
+    adg_assert_isapprox(0, cpml_angle_distance(2 * M_PI, 0));
+    adg_assert_isapprox(0, cpml_angle_distance(-2 * M_PI, 0));
+    adg_assert_isapprox(M_PI, cpml_angle_distance(0, M_PI));
+    adg_assert_isapprox(M_PI, cpml_angle_distance(M_PI, 0));
+    adg_assert_isapprox(M_PI, cpml_angle_distance(2 * M_PI, M_PI));
+    adg_assert_isapprox(M_PI, cpml_angle_distance(0, -M_PI));
+}
+
+
+int
+main(int argc, char *argv[])
+{
+    adg_test_init(&argc, &argv);
+
+    g_test_add_func("/cpml/utils/behavior/angle", _cpml_behavior_angle);
+    g_test_add_func("/cpml/utils/behavior/angle-distance", _cpml_behavior_angle_distance);
+
+    return g_test_run();
+}
-- 
2.11.4.GIT