Add a bezier curve implementation

Needed for the wacom stylus pressure curve

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

2 files changed, 203 insertions, 1 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index 6f94abe..4c9c5f6 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -3,11 +3,14 @@ AM_CPPFLAGS = $(XORG_CFLAGS) \
 	      -I$(top_srcdir)/include \
 	      -I$(top_srcdir)/src
 
-tests = test-draglock
+tests = test-draglock test-bezier
 
 noinst_PROGRAMS = $(tests)
 
 test_draglock_SOURCES = test-draglock.c
 test_draglock_LDADD = ../src/libdraglock.la
 
+test_bezier_SOURCES = test-bezier.c
+test_bezier_LDADD = ../src/libbezier.la -lm
+
 TESTS = $(tests)
diff --git a/test/test-bezier.c b/test/test-bezier.c
new file mode 100644
index 0000000..1b290a4
--- /dev/null
+++ b/test/test-bezier.c
@@ -0,0 +1,199 @@
+/*
+ * Copyright © 2016 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "bezier.h"
+
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+
+static inline void
+print_curve(int *bezier, size_t size)
+{
+	/* look at it with gnuplot, "plot 'output-file.txt'" */
+	for (int i = 0; i < size; i++)
+		printf("%d %d\n", i, bezier[i]);
+}
+
+static void
+test_linear(void)
+{
+	const int size = 2048;
+	int bezier[size];
+
+	struct bezier_control_point controls[] = {
+		{ 0.0, 0.0 },
+		{ 0.0, 0.0 },
+		{ 1.0, 1.0 },
+		{ 1.0, 1.0 }
+	};
+
+	cubic_bezier(controls, bezier, size);
+
+	assert(bezier[0] == 0);
+	assert(bezier[size - 1] == size - 1);
+
+	for (int x = 1; x < size; x++)
+		assert(bezier[x] == x);
+}
+
+/* Center point pulled down towards X axis */
+static void
+test_flattened(void)
+{
+	const int size = 2048;
+	int bezier[size];
+
+	struct bezier_control_point controls[] = {
+		{ 0.0, 0.0 },
+		{ 0.1, 0.0 },
+		{ 1.0, 0.9 },
+		{ 1.0, 1.0 }
+	};
+
+	cubic_bezier(controls, bezier, size);
+
+	assert(bezier[0] == 0);
+	assert(bezier[size - 1] == size - 1);
+
+	for (int x = 1; x < size - 1; x++) {
+		assert(bezier[x] < x);
+	}
+}
+
+/* Center point pulled up from X axis */
+static void
+test_raised(void)
+{
+	const int size = 2048;
+	int bezier[size];
+
+	struct bezier_control_point controls[] = {
+		{ 0.0, 0.0 },
+		{ 0.1, 0.4 },
+		{ 0.4, 1.0 },
+		{ 1.0, 1.0 }
+	};
+
+	cubic_bezier(controls, bezier, size);
+
+	assert(bezier[0] == 0);
+	assert(bezier[size - 1] == size - 1);
+
+	for (int x = 1; x < size; x++)
+		assert(bezier[x] >= x);
+
+	for (int x = 10; x < size - 10; x++)
+		assert(bezier[x] > x);
+}
+
+static void
+test_windy(void)
+{
+	const int size = 2048;
+	int bezier[size];
+
+	struct bezier_control_point controls[] = {
+		{ 0.0, 0.0 },
+		{ 0.0, 0.3 },
+		{ 1.0, 0.7 },
+		{ 1.0, 1.0 }
+	};
+
+	cubic_bezier(controls, bezier, size);
+
+	assert(bezier[0] == 0);
+	assert(bezier[size - 1] == size - 1);
+
+	for (int x = 1; x < size/2 - 20; x++)
+		assert(bezier[x] > x);
+
+	for (int x = size/2 + 20; x < size - 1; x++)
+		assert(bezier[x] < x);
+}
+
+static void
+test_nonzero_x_linear(void)
+{
+	const int size = 2048;
+	int bezier[size];
+	int x;
+
+	struct bezier_control_point controls[] = {
+		{ 0.2, 0.0 },
+		{ 0.2, 0.0 },
+		{ 0.8, 1.0 },
+		{ 0.8, 1.0 }
+	};
+
+	cubic_bezier(controls, bezier, size);
+
+	x = 0;
+	do {
+		assert(bezier[x] == 0);
+	} while (++x < size * 0.2 - 1);
+
+	do {
+		assert(bezier[x] > bezier[x-1]);
+	} while (++x < size * 0.8 - 1);
+
+	do {
+		assert(bezier[x] == size - 1);
+	} while (++x < size);
+}
+
+static void
+test_nonzero_y_linear(void)
+{
+	const int size = 2048;
+	int bezier[size];
+
+	struct bezier_control_point controls[] = {
+		{ 0.0, 0.2 },
+		{ 0.0, 0.2 },
+		{ 1.0, 0.8 },
+		{ 1.0, 0.8 }
+	};
+
+	cubic_bezier(controls, bezier, size);
+
+	assert(bezier[0] == (int)(size * 0.2));
+
+	for (int x = 1; x < size; x++) {
+		assert(bezier[x - 1] <= bezier[x]);
+		assert(bezier[x] >= (int)(size * 0.2));
+	}
+}
+
+int
+main(int argc, char **argv)
+{
+	test_linear();
+	test_flattened();
+	test_raised();
+	test_windy();
+	test_nonzero_x_linear();
+	test_nonzero_y_linear();
+
+	return 0;
+}