Add spring-tool, a small utility to plot spring behavior

The weston_spring is a very flexible and powerful mecanhism for driving
animations.  However, it can be a little difficult to tame, but this
little helper can plot the response of the spring to a set of initial
parameters and makes it easy to tune and tweak the spring behavior.

src/Makefile.am

@@ -280,6 +280,17 @@ cms_colord_la_SOURCES =				\
 endif
 endif
 
+noinst_PROGRAMS = spring-tool
+
+spring_tool_CFLAGS = $(GCC_CFLAGS) $(COMPOSITOR_CFLAGS)
+spring_tool_LDADD = $(COMPOSITOR_LIBS) -lm
+spring_tool_SOURCES =				\
+	spring-tool.c				\
+	animation.c				\
+	../shared/matrix.c			\
+	../shared/matrix.h			\
+	compositor.h
+
 BUILT_SOURCES =					\
 	screenshooter-server-protocol.h		\
 	screenshooter-protocol.c		\

src/spring-tool.c

@@ -0,0 +1,64 @@
+/*
+ * Copyright © 2011 Intel Corporation
+ *
+ * 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 the copyright holders not be used in
+ * advertising or publicity pertaining to distribution of the software
+ * without specific, written prior permission.  The copyright holders make
+ * no representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS 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 "compositor.h"
+
+WL_EXPORT void
+weston_surface_geometry_dirty(struct weston_surface *surface)
+{
+}
+
+WL_EXPORT int
+weston_log(const char *fmt, ...)
+{
+	return 0;
+}
+
+WL_EXPORT void
+weston_compositor_schedule_repaint(struct weston_compositor *compositor)
+{
+}
+
+int
+main(int argc, char *argv[])
+{
+	const double k = 300.0;
+	const double current = 0.0;
+	const double target = 1.0;
+	const double friction = 1400;
+
+	struct weston_spring spring;
+	uint32_t time = 0;
+
+	weston_spring_init(&spring, k, current, target);
+	spring.friction = friction;
+	spring.previous = -0.03;
+	spring.timestamp = 0;
+
+	while (!weston_spring_done(&spring)) {
+		printf("\t%d\t%f\n", time, spring.current);
+		weston_spring_update(&spring, time);
+		time += 16;
+	}
+
+	return 0;
+}