Cleaned the timeline code up nicely.

src/display/animation/timeline.c

@@ -72,6 +72,7 @@ bool timelineIsFinished(timeline_t *timeline) {
 timelineaction_t * timelineAddAction(timeline_t *timeline, float start,
   float duration
 ) {
+  if(timeline->actionCount == TIMELINE_ACTION_COUNT_MAX) return NULL;
   timelineaction_t *action = timeline->actions + (timeline->actionCount++);
   action->start = start, action->duration = duration;
   action->onStart = action->onEnd = action->onDuration = NULL;

src/display/animation/timeline.h

@@ -6,10 +6,38 @@
 #pragma once
 #include <dawn/dawn.h>
 
+/**
+ * Initializes a timeline back to its default state.
+ * 
+ * @param timeline Timeline to initialize.
+ */
 void timelineInit(timeline_t *timeline);
+
+/**
+ * Ticks the timeline. This can be done using any delta.
+ * 
+ * @param timeline Timeline to tick
+ * @param delta Delta to tick.
+ */
 void timelineUpdate(timeline_t *timeline, float delta);
+
+/**
+ * Returns true if every action in the timeline has finished.
+ * 
+ * @param timeline Timeline to check
+ * @return True if finished, otherwise false.
+ */
 bool timelineIsFinished(timeline_t *timeline);
 
+/**
+ * Adds an action to the timeline. This will initialize the action callbacks to
+ * NULL, you will need to initialize your own callbacks.
+ * 
+ * @param timeline Timeline to add to.
+ * @param start Start time.
+ * @param duration Duration time
+ * @return Pointer to the timeline action or NULL if the list is full.
+ */
 timelineaction_t * timelineAddAction(timeline_t *timeline, float start,
   float duration
 );