The animation player

pz.AnimationPlayer plays the clips you give it, one at a time, and gives each widget its part with player["target"].

self.player = pz.AnimationPlayer(INTRO, IDLE, "ui.pzanim", autoplay="intro",
                                 on_started=..., on_finished=...)

• Sources: clips, lists of clips, libraries or paths of .pzanim files.
• Where to keep it: in an attribute of the app (or of a window). There it finds its owner, the object whose attributes and methods the tracks and calls use, and keeps itself running.
• Targets: widget.animate(self.player["card"]) gives a widget the card target. Every widget that uses the same target follows it.

Controls

Call	What it does
play(name, speed=1, backwards=False, restart=False)	Plays a clip, or goes on with the current one. A clip that is already playing goes on unless restart; a finished one starts over.
play_backwards(name)	Plays it backwards from the end.
pause(), resume(), toggle()	Stops the time and starts it again.
stop(reset=False)	Goes back to the first frame and clears the queue. With reset=True the widgets go back to their own values.
seek(seconds)	Jumps to a time. Calls between don’t run.
advance(seconds)	Moves the time by hand and runs the calls on the way (handy in tests).
queue(name), clear_queue()	Plays a clip when the current one ends.
speed	The playback speed of every clip (2 is twice as fast). play(speed=...) multiplies it.

def replay(self):
    self.player.play("intro", restart=True)
    self.player.queue("idle")            # loops after the intro

def set_speed(self, label):
    self.player.speed = float(label.rstrip("×"))

State and events

Read	Gives
current	The name of the clip playing or paused (None when stopped).
position, length	Where the playhead is and how long the clip is, in seconds.
playing, paused, finished	What the player is doing.
queued	The clips waiting to play.
names, has(name), clip(name)	The clips it knows.
value(path)	The value the current clip gives a path right now: player.value(":score").

on_started(name) and on_finished(name) are called when a clip starts and when it ends (looping clips never end). A slider bound to position and seek makes a scrubber:

ui.slider(p.position, p.seek, min=0, max=p.length, step=0.01)

It only wakes your app when needed

Widget tracks play natively and never need your code. A clip with attribute tracks updates them up to fps times a second (60 by default, pz.AnimationPlayer(..., fps=30) for less). Without them, the player only wakes up for the next call or the end of the clip.

Libraries and .pzanim files

Clips are immutable values, so you can share them between players and apps. An AnimationLibrary groups them and saves them in a .pzanim file (JSON) that you can keep in your project and load in any app:

library = pz.AnimationLibrary([INTRO, IDLE], name="ui")
library.save("ui.pzanim")

player = pz.AnimationPlayer("ui.pzanim")      # clips named "ui/intro", "ui/idle"
player.play("ui/intro")
library = pz.load_animations("ui.pzanim")

A library also has add, remove, rename and names. Forms made in Pyzed Design keep their clips inside the .pzform; see the Animation panel.

Reusing clips

Clip methods return a new clip, so the original stays as it is:

• clip.retarget({"card": "panel"}) moves the clip’s tracks to other targets.
• clip.animation("card") turns one target’s tracks into a pz.Animation. Play it with animate() without a player, or give it a name with pz.define_animation.
• clip.with_key(path, time, value), without_key, with_track and without_track edit it.
• clip.to_dict() and pz.Clip.from_dict() turn it into JSON-friendly data and back.