Animations: blending out and restart (#106)

Animations.md

@@ -88,6 +88,23 @@ the value already mixed, so nothing jumps. The blend starts only when the animat
 again every frame while it already leads, it keeps the blend it has. Winning back one that still runs
 blends again with the time given then; the tab's preview plays one animation and has no blend.
 
+**Blending out.** `Stop animation` has a *blend (s)* port as well. At 0 it ends the animation where it
+stands and the values stay; above 0 the animation fades out over that many seconds instead, back to
+what lies below it: live what an animation started earlier writes there, otherwise the value the row
+found when the animation started. A texture, a boolean, a text or a choice goes back at once. A paused
+animation fades out too. `Play animation` has *blend out (s)* for *Once (reset)*: when its frames run
+out it fades back to where it started over that many seconds instead of jumping; *On animation
+finished* fires when the frames run out, not when the fade ends. Playing an animation again while it
+fades out turns it round from where it stands, without a jump — a *Once (reset)* pass that already ran
+out starts over, blending in from the value the fade had reached.
+
+**Restart.** `Play animation` has a *restart* switch, off by default. On, an animation that is
+already running, paused or fading out starts over from its first frame and counts as started last;
+with *blend (s)* above 0 it blends in from where the property stands, otherwise it jumps. Its starting
+values stay those of its first start, so a relative row does not add up. Played with *restart* on
+every frame, an animation never gets past its first frame — use it on a single event such as a key
+press.
+
 **It runs in play only.** The Scene and Container tabs show the objects as stored; the edit mode
 has no clock. The fastest way in is right-clicking a texture → **Create animation from texture**,
 which makes a sprite of the texture and an animation over it with a `texture` row keyed frame by