cookbook: Looping animation examples

Added code examples for creating a looped animation with
each of the animation approaches (implicit, ClutterAnimation,
ClutterState).

doc/cookbook/examples/animations-looping-implicit.c

@@ -0,0 +1,87 @@
+#include <stdlib.h>
+#include <clutter/clutter.h>
+
+static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
+static const ClutterColor red_color = { 0xff, 0x00, 0x00, 0xff };
+
+typedef struct
+{
+  ClutterActor    *actor;
+  ClutterTimeline *timeline;
+} State;
+
+static void
+invert_timeline_cb (ClutterTimeline *timeline,
+                    gpointer         user_data)
+{
+  ClutterTimelineDirection direction = clutter_timeline_get_direction (timeline);
+
+  if (direction == CLUTTER_TIMELINE_FORWARD)
+    direction = CLUTTER_TIMELINE_BACKWARD;
+  else
+    direction = CLUTTER_TIMELINE_FORWARD;
+
+  clutter_timeline_set_direction (timeline, direction);
+}
+
+static gboolean
+key_pressed_cb (ClutterActor *actor,
+                ClutterEvent *event,
+                gpointer      user_data)
+{
+  State *state = (State *) user_data;
+
+  /* only start animating if actor isn't animating already */
+  if (clutter_actor_get_animation (state->actor) == NULL)
+    clutter_actor_animate_with_timeline (state->actor,
+                                         CLUTTER_LINEAR,
+                                         state->timeline,
+                                         "x", 50.0,
+                                         NULL);
+
+  return TRUE;
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  State *state = g_new0 (State, 1);
+
+  ClutterActor *stage;
+
+  clutter_init (&argc, &argv);
+
+  stage = clutter_stage_get_default ();
+  clutter_actor_set_size (stage, 300, 200);
+  clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
+  g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
+
+  state->actor = clutter_rectangle_new_with_color (&red_color);
+  clutter_actor_set_size (state->actor, 100, 100);
+  clutter_actor_set_position (state->actor, 150, 50);
+
+  state->timeline = clutter_timeline_new (1000);
+  clutter_timeline_set_loop (state->timeline, TRUE);
+
+  g_signal_connect (stage,
+                    "key-press-event",
+                    G_CALLBACK (key_pressed_cb),
+                    state);
+
+  g_signal_connect (state->timeline,
+                    "completed",
+                    G_CALLBACK (invert_timeline_cb),
+                    NULL);
+
+  clutter_container_add_actor (CLUTTER_CONTAINER (stage), state->actor);
+
+  clutter_actor_show (stage);
+
+  clutter_main ();
+
+  g_object_unref (state->timeline);
+  g_free (state);
+
+  return EXIT_SUCCESS;
+}