Merge pull request #5600 from dotCooCoo/feat/actions-playback-options

Actions: Playback Options plays actions accelerated, step by step or with a pause between steps

crates/ui-egui/src/app.rs

@@ -370,6 +370,12 @@ impl VectorcraftApp {
         }
         self.flush_clipboard_out(ctx);
         self.drain_inbox();
+        // An action playing at Step by Step or Pause For runs its next step when it is due, after
+        // the control requests and opened files above: a Stop or a document switch they bring
+        // comes first.
+        if let Some(wait) = crate::panels::actions::tick_playback(self, now) {
+            ctx.request_repaint_after(std::time::Duration::from_secs_f64(wait));
+        }
         if self.viewport_hidden(ctx) && (self.needs_hidden_paint() || (!dialog_was_open && self.ui.dialog.is_some())) {
             // A plain repaint runs only logic in a hidden window: the ui that applies injected
             // input, shows a queued dialog or issues a capture needs this command. egui-winit
@@ -494,6 +500,8 @@ impl VectorcraftApp {
             return;
         }
         crate::state::sync_zoom_stops_display_print_size(self.session.prefs.display_print_size);
+        // Whether this pass draws the last step of an action playing at Step by Step.
+        let step_held = crate::panels::actions::playback_held(self);
         let t0 = now_ms();
         widgets::set_dialog_open(&ctx, self.ui.dialog.is_some());
         // The canvas records this pass's IME caret geometry; a pass that draws no canvas has none.
@@ -558,6 +566,10 @@ impl VectorcraftApp {
         if !ctx.will_discard() {
             self.perf.frame_ms = now_ms() - t0;
             self.issue_screenshots(&ctx);
+            // A hidden window's pass shows nothing, so the step waits for a pass the user sees.
+            if step_held && !self.viewport_hidden(&ctx) {
+                crate::panels::actions::playback_drawn(self);
+            }
         }
         let _ = json!(null);
     }

crates/ui-egui/src/dialogs.rs

@@ -9,6 +9,7 @@
 mod about;
 pub mod action_batch;
 pub mod action_new;
+pub mod action_playback;
 pub mod action_set_options;
 pub mod artboard_options;
 pub mod blend_options;
@@ -365,6 +366,7 @@ registry! {
     ActionBatch: [action_batch::KIND] => action_batch::SPEC,
     ActionSetOptions: [action_set_options::KIND] => action_set_options::SPEC,
     ActionNew: [action_new::KIND] => action_new::SPEC,
+    ActionPlayback: [action_playback::KIND] => action_playback::SPEC,
     SliceOptions: [slices::OPTIONS] => slices::OPTIONS_SPEC,
     DivideSlices: [slices::DIVIDE] => slices::DIVIDE_SPEC,
     EpsOptions: [eps_options::KIND] => eps_options::SPEC,

crates/ui-egui/src/dialogs/action_playback.rs

@@ -0,0 +1,48 @@
+//! Actions panel menu › Playback Options…: the speed actions play at (`ui.action.playbackOptions`).
+//!
+//! Fields: `speed` (`accelerated`, `step` or `pause`) and `seconds`, the pause between steps with
+//! `pause`. OK sets them; an invalid value is an error, and the dialog stays open.
+
+use serde_json::{Value, json};
+
+use super::DialogSpec;
+use crate::state::Dialog;
+use crate::{VectorcraftApp, widgets};
+
+/// The dialog kind of Playback Options.
+pub const KIND: &str = "actionPlayback";
+
+pub(super) const SPEC: DialogSpec = DialogSpec { heading: |_| tl!("Playback Options").into(), body, confirm, min_width: 260.0, ..DialogSpec::FORM };
+
+/// Open Playback Options with the speed and pause actions play with now.
+pub fn open(app: &mut VectorcraftApp) {
+    let o = app.ui.action_playback;
+    app.ui.dialog = Some(Dialog::new(KIND, json!({"speed": o.speed, "seconds": o.seconds})));
+}
+
+fn body(_app: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> bool {
+    let speed = d.str("speed");
+    for (value, label) in [("accelerated", tl!("Accelerated")), ("step", tl!("Step by Step"))] {
+        if widgets::radio(ui, label, speed == value, true) {
+            d.fields.insert("speed".into(), json!(value));
+        }
+    }
+    ui.horizontal(|ui| {
+        let pause = tl!("Pause For");
+        if widgets::radio(ui, pause, speed == "pause", true) {
+            d.fields.insert("speed".into(), json!("pause"));
+        }
+        let range = f64::from(*crate::panels::actions::PAUSE_SECONDS.start())..=f64::from(*crate::panels::actions::PAUSE_SECONDS.end());
+        if let Some(n) = widgets::range_field_named(ui, "action-pause-seconds", Some(pause), d.f64("seconds", *range.start()), range, "s", 0, 50.0) {
+            d.fields.insert("seconds".into(), json!(n as u64));
+        }
+    });
+    false
+}
+
+fn confirm(app: &mut VectorcraftApp, d: &Dialog) -> Result<Value, String> {
+    let params = json!({"speed": d.str("speed"), "seconds": d.fields.get("seconds").cloned().unwrap_or(Value::Null)});
+    let r = app.run(crate::panels::actions::PLAYBACK_OPTIONS, params)?;
+    app.ui.dialog = None;
+    Ok(r)
+}

crates/ui-egui/src/i18n/bg.tsv

@@ -5502,6 +5502,10 @@ theme	Appearance	Външен вид
 	Movie Clip	Филмов клип
 @msg	name is empty	името е празно
 @msg	an action is already recording	вече се записва действие
+@msg	an action is already playing	вече се възпроизвежда действие
+@msg	the action stopped playing: its document is no longer active	действието спря: документът му вече не е активен
+@msg	speed must be accelerated, step or pause	speed трябва да е accelerated, step или pause
+@msg	seconds must be a whole number from 1 to 60	seconds трябва да е цяло число от 1 до 60
 @msg	no such function key	няма такъв функционален клавиш
 @msg	no such color	няма такъв цвят
 @msg	{_1} cannot be used on Windows	{_1} не може да се използва в Windows
@@ -5652,6 +5656,11 @@ axis	Y Axis	Y ос
 	Set Options	Опции на набора
 	Action Options…	Опции на действието…
 	Action Options	Опции на действието
+	Playback Options…	Опции за възпроизвеждане…
+	Playback Options	Опции за възпроизвеждане
+	Accelerated	Ускорено
+	Step by Step	Стъпка по стъпка
+	Pause For	Пауза за
 	Rename Action	Преименуване на действие
 	New Action…	Ново действие…
 	New Action	Ново действие

crates/ui-egui/src/i18n/bs.tsv

@@ -5506,6 +5506,10 @@ mark-style	Japanese	Japanski
 	Movie Clip	Filmski klip
 @msg	name is empty	naziv je prazan
 @msg	an action is already recording	akcija se već snima
+@msg	an action is already playing	akcija se već reproducira
+@msg	the action stopped playing: its document is no longer active	reprodukcija akcije je zaustavljena: njen dokument više nije aktivan
+@msg	speed must be accelerated, step or pause	speed mora biti accelerated, step ili pause
+@msg	seconds must be a whole number from 1 to 60	seconds mora biti cijeli broj od 1 do 60
 @msg	no such function key	nema takve funkcijske tipke
 @msg	no such color	nema takve boje
 @msg	{_1} cannot be used on Windows	{_1} se ne može koristiti na Windowsu
@@ -5675,6 +5679,11 @@ axis	Y Axis	Y osa
 	Set Options	Opcije skupa
 	Action Options…	Opcije akcije…
 	Action Options	Opcije akcije
+	Playback Options…	Opcije reprodukcije…
+	Playback Options	Opcije reprodukcije
+	Accelerated	Ubrzano
+	Step by Step	Korak po korak
+	Pause For	Pauza od
 	Rename Action	Preimenuj akciju
 	New Action…	Nova akcija…
 	New Action	Nova akcija

crates/ui-egui/src/i18n/ca.tsv

@@ -3791,6 +3791,11 @@ digits	Malayalam	Malaiàlam
 	Set Options	Defineix les opcions
 	Action Options…	Opcions de l’acció…
 	Action Options	Opcions de l’acció
+	Playback Options…	Opcions de reproducció…
+	Playback Options	Opcions de reproducció
+	Accelerated	Accelerada
+	Step by Step	Pas a pas
+	Pause For	Pausa de
 	Rename Action	Canvia el nom de l’acció
 	New Action…	Acció nova…
 	New Action	Acció nova
@@ -5187,6 +5192,10 @@ digits	Malayalam	Malaiàlam
 @msg	Multichannel PSD files can't be read: save it in RGB, CMYK or Grayscale mode	Els fitxers PSD multicanal no es poden llegir: deseu-los en mode RGB, CMYK o escala de grisos
 @msg	name is empty	el nom és buit
 @msg	an action is already recording	ja s’està enregistrant una acció
+@msg	an action is already playing	ja s’està reproduint una acció
+@msg	the action stopped playing: its document is no longer active	l’acció s’ha aturat: el seu document ja no és l’actiu
+@msg	speed must be accelerated, step or pause	speed ha de ser accelerated, step o pause
+@msg	seconds must be a whole number from 1 to 60	seconds ha de ser un nombre enter de l’1 al 60
 @msg	no such function key	no existeix aquesta tecla de funció
 @msg	no such color	no existeix aquest color
 @msg	{_1} cannot be used on Windows	{_1} no es pot fer servir al Windows

crates/ui-egui/src/i18n/cs.tsv

@@ -5592,6 +5592,10 @@ mark-style	Japanese	Japonské
 	Movie Clip	Filmový klip
 @msg	name is empty	název je prázdný
 @msg	an action is already recording	akce se už zaznamenává
+@msg	an action is already playing	akce se už přehrává
+@msg	the action stopped playing: its document is no longer active	přehrávání akce se zastavilo: její dokument už není aktivní
+@msg	speed must be accelerated, step or pause	speed musí být accelerated, step nebo pause
+@msg	seconds must be a whole number from 1 to 60	seconds musí být celé číslo od 1 do 60
 @msg	no such function key	taková funkční klávesa neexistuje
 @msg	no such color	taková barva neexistuje
 @msg	{_1} cannot be used on Windows	Zkratku {_1} nelze ve Windows použít
@@ -5766,6 +5770,11 @@ axis	Y Axis	osa Y
 	Set Options	Možnosti sady
 	Action Options…	Možnosti akce…
 	Action Options	Možnosti akce
+	Playback Options…	Možnosti přehrávání…
+	Playback Options	Možnosti přehrávání
+	Accelerated	Zrychleně
+	Step by Step	Krok za krokem
+	Pause For	Pozastavit na
 	Rename Action	Přejmenovat akci
 	New Action…	Nová akce…
 	New Action	Nová akce

crates/ui-egui/src/i18n/da.tsv

@@ -5387,6 +5387,10 @@ swatch	Bright Violet	Kraftig violet
 	Movie Clip	Filmklip
 @msg	name is empty	navnet er tomt
 @msg	an action is already recording	en handling optages allerede
+@msg	an action is already playing	en handling afspilles allerede
+@msg	the action stopped playing: its document is no longer active	handlingen stoppede: dens dokument er ikke længere aktivt
+@msg	speed must be accelerated, step or pause	speed skal være accelerated, step eller pause
+@msg	seconds must be a whole number from 1 to 60	seconds skal være et heltal fra 1 til 60
 @msg	no such function key	ingen sådan funktionstast
 @msg	no such color	ingen sådan farve
 @msg	{_1} cannot be used on Windows	{_1} kan ikke bruges i Windows
@@ -5669,6 +5673,11 @@ axis	Y Axis	Y-akse
 	Set Options	Indstillinger for sæt
 	Action Options…	Indstillinger for handling…
 	Action Options	Indstillinger for handling
+	Playback Options…	Afspilningsindstillinger…
+	Playback Options	Afspilningsindstillinger
+	Accelerated	Accelereret
+	Step by Step	Trin for trin
+	Pause For	Pause på
 	Rename Action	Omdøb handling
 	New Action…	Ny handling…
 	New Action	Ny handling

crates/ui-egui/src/i18n/de.tsv

@@ -5170,6 +5170,10 @@ effect	Soft	Weich
 	Movie Clip	Movieclip
 @msg	name is empty	Name ist leer
 @msg	an action is already recording	eine Aktion wird bereits aufgezeichnet
+@msg	an action is already playing	eine Aktion wird bereits abgespielt
+@msg	the action stopped playing: its document is no longer active	die Aktion wurde angehalten: ihr Dokument ist nicht mehr aktiv
+@msg	speed must be accelerated, step or pause	speed muss accelerated, step oder pause sein
+@msg	seconds must be a whole number from 1 to 60	seconds muss eine ganze Zahl von 1 bis 60 sein
 @msg	no such function key	keine solche Funktionstaste
 @msg	no such color	keine solche Farbe
 @msg	{_1} cannot be used on Windows	{_1} kann unter Windows nicht verwendet werden
@@ -5348,6 +5352,11 @@ axis	Y Axis	Y-Achse
 	Set Options	Satzoptionen
 	Action Options…	Aktionsoptionen…
 	Action Options	Aktionsoptionen
+	Playback Options…	Wiedergabeoptionen…
+	Playback Options	Wiedergabeoptionen
+	Accelerated	Beschleunigt
+	Step by Step	Schrittweise
+	Pause For	Pause von
 	Rename Action	Aktion umbenennen
 	New Action…	Neue Aktion…
 	New Action	Neue Aktion

crates/ui-egui/src/i18n/el.tsv

@@ -5543,6 +5543,10 @@ effect	Points	Σημεία
 	Movie Clip	Κλιπ ταινίας
 @msg	name is empty	το όνομα είναι κενό
 @msg	an action is already recording	μια ενέργεια καταγράφεται ήδη
+@msg	an action is already playing	μια ενέργεια αναπαράγεται ήδη
+@msg	the action stopped playing: its document is no longer active	η αναπαραγωγή της ενέργειας σταμάτησε: το έγγραφό της δεν είναι πλέον ενεργό
+@msg	speed must be accelerated, step or pause	το speed πρέπει να είναι accelerated, step ή pause
+@msg	seconds must be a whole number from 1 to 60	το seconds πρέπει να είναι ακέραιος από 1 έως 60
 @msg	no such function key	δεν υπάρχει τέτοιο πλήκτρο λειτουργίας
 @msg	no such color	δεν υπάρχει τέτοιο χρώμα
 @msg	{_1} cannot be used on Windows	Το {_1} δεν μπορεί να χρησιμοποιηθεί στα Windows
@@ -5717,6 +5721,11 @@ axis	Y Axis	Άξονας Y
 	Set Options	Επιλογές συνόλου
 	Action Options…	Επιλογές ενέργειας…
 	Action Options	Επιλογές ενέργειας
+	Playback Options…	Επιλογές αναπαραγωγής…
+	Playback Options	Επιλογές αναπαραγωγής
+	Accelerated	Επιταχυμένα
+	Step by Step	Βήμα προς βήμα
+	Pause For	Παύση για
 	Rename Action	Μετονομασία ενέργειας
 	New Action…	Νέα ενέργεια…
 	New Action	Νέα ενέργεια

crates/ui-egui/src/i18n/es.tsv

@@ -5533,6 +5533,10 @@ mark-style	Japanese	Japonesas
 	Movie Clip	Clip de película
 @msg	name is empty	el nombre está vacío
 @msg	an action is already recording	ya se está grabando una acción
+@msg	an action is already playing	ya se está reproduciendo una acción
+@msg	the action stopped playing: its document is no longer active	la acción se detuvo: su documento ya no es el activo
+@msg	speed must be accelerated, step or pause	speed debe ser accelerated, step o pause
+@msg	seconds must be a whole number from 1 to 60	seconds debe ser un número entero de 1 a 60
 @msg	no such function key	no existe esa tecla de función
 @msg	no such color	no existe ese color
 @msg	{_1} cannot be used on Windows	{_1} no se puede usar en Windows
@@ -5707,6 +5711,11 @@ axis	Y Axis	Eje Y
 	Set Options	Opciones de conjunto
 	Action Options…	Opciones de acción…
 	Action Options	Opciones de acción
+	Playback Options…	Opciones de reproducción…
+	Playback Options	Opciones de reproducción
+	Accelerated	Acelerada
+	Step by Step	Paso a paso
+	Pause For	Pausa de
 	Rename Action	Cambiar nombre de acción
 	New Action…	Nueva acción…
 	New Action	Nueva acción

crates/ui-egui/src/i18n/fi.tsv

@@ -5555,6 +5555,10 @@ mark-style	Japanese	Japanilainen
 	Movie Clip	Elokuvaleike
 @msg	name is empty	nimi on tyhjä
 @msg	an action is already recording	toimintoa nauhoitetaan jo
+@msg	an action is already playing	toimintoa toistetaan jo
+@msg	the action stopped playing: its document is no longer active	toiminnon toisto pysähtyi: sen asiakirja ei ole enää aktiivinen
+@msg	speed must be accelerated, step or pause	speed on oltava accelerated, step tai pause
+@msg	seconds must be a whole number from 1 to 60	seconds on oltava kokonaisluku 1:stä 60:een
 @msg	no such function key	toimintonäppäintä ei ole
 @msg	no such color	väriä ei ole
 @msg	{_1} cannot be used on Windows	{_1} ei ole käytettävissä Windowsissa
@@ -5796,6 +5800,11 @@ axis	Y Axis	Y-akseli
 	Set Options	Sarjan asetukset
 	Action Options…	Toiminnon asetukset…
 	Action Options	Toiminnon asetukset
+	Playback Options…	Toistoasetukset…
+	Playback Options	Toistoasetukset
+	Accelerated	Nopeutettu
+	Step by Step	Vaihe kerrallaan
+	Pause For	Tauko
 	Rename Action	Nimeä toiminto uudelleen
 	New Action…	Uusi toiminto…
 	New Action	Uusi toiminto

crates/ui-egui/src/i18n/fr.tsv

@@ -5587,6 +5587,10 @@ theme	Appearance	Apparence
 	Movie Clip	Clip
 @msg	name is empty	le nom est vide
 @msg	an action is already recording	un script est déjà en cours d’enregistrement
+@msg	an action is already playing	un script est déjà en cours d’exécution
+@msg	the action stopped playing: its document is no longer active	le script s’est arrêté : son document n’est plus le document actif
+@msg	speed must be accelerated, step or pause	speed doit valoir accelerated, step ou pause
+@msg	seconds must be a whole number from 1 to 60	seconds doit être un nombre entier de 1 à 60
 @msg	no such function key	touche de fonction inexistante
 @msg	no such color	couleur inexistante
 @msg	{_1} cannot be used on Windows	{_1} ne peut pas être utilisé sous Windows
@@ -5761,6 +5765,11 @@ axis	Y Axis	Axe Y
 	Set Options	Options du jeu
 	Action Options…	Options de script…
 	Action Options	Options de script
+	Playback Options…	Options d’exécution…
+	Playback Options	Options d’exécution
+	Accelerated	Accélérée
+	Step by Step	Pas à pas
+	Pause For	Pause de
 	Rename Action	Renommer le script
 	New Action…	Nouveau script…
 	New Action	Nouveau script

crates/ui-egui/src/i18n/hu.tsv

@@ -5575,6 +5575,10 @@ imageTrace	Outline	Körvonal
 	Movie Clip	Mozgóklip
 @msg	name is empty	a név üres
 @msg	an action is already recording	már folyik egy művelet felvétele
+@msg	an action is already playing	már folyik egy művelet lejátszása
+@msg	the action stopped playing: its document is no longer active	a művelet lejátszása leállt: a dokumentuma már nem az aktív
+@msg	speed must be accelerated, step or pause	a speed értéke accelerated, step vagy pause lehet
+@msg	seconds must be a whole number from 1 to 60	a seconds értéke 1 és 60 közötti egész szám lehet
 @msg	no such function key	nincs ilyen funkcióbillentyű
 @msg	no such color	nincs ilyen szín
 @msg	{_1} cannot be used on Windows	A(z) {_1} nem használható Windows rendszeren
@@ -5749,6 +5753,11 @@ axis	Y Axis	Y tengely
 	Set Options	Készlet beállításai
 	Action Options…	Művelet beállításai…
 	Action Options	Művelet beállításai
+	Playback Options…	Lejátszási beállítások…
+	Playback Options	Lejátszási beállítások
+	Accelerated	Gyorsított
+	Step by Step	Lépésenként
+	Pause For	Szünet
 	Rename Action	Művelet átnevezése
 	New Action…	Új művelet…
 	New Action	Új művelet

crates/ui-egui/src/i18n/id.tsv

@@ -5387,6 +5387,10 @@ swatch	Bright Violet	Violet cerah
 	Movie Clip	Klip film
 @msg	name is empty	nama kosong
 @msg	an action is already recording	sebuah tindakan sedang direkam
+@msg	an action is already playing	sebuah tindakan sedang diputar
+@msg	the action stopped playing: its document is no longer active	tindakan berhenti diputar: dokumennya tidak lagi aktif
+@msg	speed must be accelerated, step or pause	speed harus accelerated, step, atau pause
+@msg	seconds must be a whole number from 1 to 60	seconds harus bilangan bulat dari 1 sampai 60
 @msg	no such function key	tidak ada tombol fungsi seperti itu
 @msg	no such color	tidak ada warna seperti itu
 @msg	{_1} cannot be used on Windows	{_1} tidak dapat digunakan di Windows
@@ -5669,6 +5673,11 @@ axis	Y Axis	Sumbu Y
 	Set Options	Opsi set
 	Action Options…	Opsi tindakan…
 	Action Options	Opsi tindakan
+	Playback Options…	Opsi pemutaran…
+	Playback Options	Opsi pemutaran
+	Accelerated	Dipercepat
+	Step by Step	Langkah demi langkah
+	Pause For	Jeda selama
 	Rename Action	Ganti nama tindakan
 	New Action…	Tindakan baru…
 	New Action	Tindakan baru

crates/ui-egui/src/i18n/it.tsv

@@ -5205,6 +5205,10 @@ lighting	Light	Luce
 	Movie Clip	Clip filmato
 @msg	name is empty	il nome è vuoto
 @msg	an action is already recording	è già in corso la registrazione di un’azione
+@msg	an action is already playing	è già in corso la riproduzione di un’azione
+@msg	the action stopped playing: its document is no longer active	la riproduzione dell’azione si è interrotta: il suo documento non è più attivo
+@msg	speed must be accelerated, step or pause	speed deve essere accelerated, step o pause
+@msg	seconds must be a whole number from 1 to 60	seconds deve essere un numero intero da 1 a 60
 @msg	no such function key	tasto funzione inesistente
 @msg	no such color	colore inesistente
 @msg	{_1} cannot be used on Windows	{_1} non può essere usato su Windows
@@ -5382,6 +5386,11 @@ axis	Y Axis	Asse Y
 	Set Options	Opzioni set
 	Action Options…	Opzioni azione…
 	Action Options	Opzioni azione
+	Playback Options…	Opzioni di riproduzione…
+	Playback Options	Opzioni di riproduzione
+	Accelerated	Accelerata
+	Step by Step	Passo per passo
+	Pause For	Pausa di
 	Rename Action	Rinomina azione
 	New Action…	Nuova azione…
 	New Action	Nuova azione

crates/ui-egui/src/i18n/ja.tsv

@@ -5248,6 +5248,10 @@ lighting	Light	ライト
 	Movie Clip	ムービークリップ
 @msg	name is empty	名前が空です
 @msg	an action is already recording	すでにアクションを記録中です
+@msg	an action is already playing	すでにアクションを再生中です
+@msg	the action stopped playing: its document is no longer active	アクションの再生を停止しました: そのドキュメントはアクティブではなくなりました
+@msg	speed must be accelerated, step or pause	speed には accelerated、step または pause を指定してください
+@msg	seconds must be a whole number from 1 to 60	seconds には 1 から 60 までの整数を指定してください
 @msg	no such function key	指定されたファンクションキーが見つかりません
 @msg	no such color	指定されたカラーが見つかりません
 @msg	{_1} cannot be used on Windows	{_1} は Windows では使用できません
@@ -5447,6 +5451,11 @@ axis	Y Axis	Y 軸
 	Set Options	セットオプション
 	Action Options…	アクションオプション…
 	Action Options	アクションオプション
+	Playback Options…	再生オプション…
+	Playback Options	再生オプション
+	Accelerated	高速
+	Step by Step	ステップ実行
+	Pause For	一時停止
 	Rename Action	アクション名を変更
 	New Action…	新規アクション…
 	New Action	新規アクション

crates/ui-egui/src/i18n/ka.tsv

@@ -5300,6 +5300,10 @@ imageTrace	Outline	კონტური
 	Movie Clip	ანიმაციური კლიპი
 @msg	name is empty	სახელი ცარიელია
 @msg	an action is already recording	მოქმედება უკვე იწერება
+@msg	an action is already playing	მოქმედება უკვე სრულდება
+@msg	the action stopped playing: its document is no longer active	მოქმედება შეჩერდა: მისი დოკუმენტი აღარ არის აქტიური
+@msg	speed must be accelerated, step or pause	speed უნდა იყოს accelerated, step ან pause
+@msg	seconds must be a whole number from 1 to 60	seconds უნდა იყოს მთელი რიცხვი 1-დან 60-მდე
 @msg	no such function key	ასეთი ფუნქციური კლავიში არ არის
 @msg	no such color	ასეთი ფერი არ არის
 @msg	{_1} cannot be used on Windows	{_1} ვერ გამოიყენება Windows-ში
@@ -5688,6 +5692,11 @@ axis	Y Axis	Y ღერძი
 	Set Options	ნაკრების პარამეტრები
 	Action Options…	მოქმედების პარამეტრები…
 	Action Options	მოქმედების პარამეტრები
+	Playback Options…	შესრულების პარამეტრები…
+	Playback Options	შესრულების პარამეტრები
+	Accelerated	დაჩქარებული
+	Step by Step	ნაბიჯ-ნაბიჯ
+	Pause For	პაუზა
 	Rename Action	მოქმედების სახელის შეცვლა
 	New Action…	ახალი მოქმედება…
 	New Action	ახალი მოქმედება

crates/ui-egui/src/i18n/ko.tsv

@@ -5166,6 +5166,10 @@ lighting	Light	광원
 	Movie Clip	무비 클립
 @msg	name is empty	이름이 비어 있습니다
 @msg	an action is already recording	이미 액션을 기록하고 있습니다
+@msg	an action is already playing	이미 액션을 재생하고 있습니다
+@msg	the action stopped playing: its document is no longer active	액션 재생이 중지되었습니다: 해당 문서가 더 이상 활성 상태가 아닙니다
+@msg	speed must be accelerated, step or pause	speed는 accelerated, step 또는 pause여야 합니다
+@msg	seconds must be a whole number from 1 to 60	seconds는 1에서 60 사이의 정수여야 합니다
 @msg	no such function key	해당 기능 키가 없습니다
 @msg	no such color	해당 색상이 없습니다
 @msg	{_1} cannot be used on Windows	{_1}은(는) Windows에서 사용할 수 없습니다
@@ -5343,6 +5347,11 @@ axis	Y Axis	Y축
 	Set Options	세트 옵션
 	Action Options…	액션 옵션…
 	Action Options	액션 옵션
+	Playback Options…	재생 옵션…
+	Playback Options	재생 옵션
+	Accelerated	가속
+	Step by Step	단계별
+	Pause For	일시 정지
 	Rename Action	액션 이름 바꾸기
 	New Action…	새 액션…
 	New Action	새 액션

crates/ui-egui/src/i18n/nl.tsv

@@ -5395,6 +5395,10 @@ swatch	Bright Violet	Felviolet
 	Movie Clip	Filmclip
 @msg	name is empty	naam is leeg
 @msg	an action is already recording	er wordt al een actie opgenomen
+@msg	an action is already playing	er wordt al een actie afgespeeld
+@msg	the action stopped playing: its document is no longer active	de actie is gestopt: het document ervan is niet meer actief
+@msg	speed must be accelerated, step or pause	speed moet accelerated, step of pause zijn
+@msg	seconds must be a whole number from 1 to 60	seconds moet een geheel getal van 1 tot 60 zijn
 @msg	no such function key	functietoets bestaat niet
 @msg	no such color	kleur bestaat niet
 @msg	{_1} cannot be used on Windows	{_1} kan niet worden gebruikt in Windows
@@ -5713,6 +5717,11 @@ axis	Y Axis	Y-as
 	Set Options	Setopties
 	Action Options…	Actieopties…
 	Action Options	Actieopties
+	Playback Options…	Afspeelopties…
+	Playback Options	Afspeelopties
+	Accelerated	Versneld
+	Step by Step	Stap voor stap
+	Pause For	Pauzeren
 	Rename Action	Actie hernoemen
 	New Action…	Nieuwe actie…
 	New Action	Nieuwe actie

crates/ui-egui/src/i18n/pl.tsv

@@ -5445,6 +5445,10 @@ mark-style	Japanese	Japońskie
 	Movie Clip	Klip filmowy
 @msg	name is empty	nazwa jest pusta
 @msg	an action is already recording	operacja jest już nagrywana
+@msg	an action is already playing	operacja jest już odtwarzana
+@msg	the action stopped playing: its document is no longer active	odtwarzanie operacji zatrzymano: jej dokument nie jest już aktywny
+@msg	speed must be accelerated, step or pause	speed musi mieć wartość accelerated, step lub pause
+@msg	seconds must be a whole number from 1 to 60	seconds musi być liczbą całkowitą od 1 do 60
 @msg	no such function key	brak takiego klawisza funkcyjnego
 @msg	no such color	brak takiego koloru
 @msg	{_1} cannot be used on Windows	Skrótu {_1} nie można używać w systemie Windows
@@ -5619,6 +5623,11 @@ axis	Y Axis	Oś Y
 	Set Options	Opcje zestawu
 	Action Options…	Opcje operacji…
 	Action Options	Opcje operacji
+	Playback Options…	Opcje odtwarzania…
+	Playback Options	Opcje odtwarzania
+	Accelerated	Przyspieszone
+	Step by Step	Krok po kroku
+	Pause For	Pauza
 	Rename Action	Zmień nazwę operacji
 	New Action…	Nowa operacja…
 	New Action	Nowa operacja

crates/ui-egui/src/i18n/pt-br.tsv

@@ -5507,6 +5507,10 @@ mark-style	Japanese	Japonesas
 # Symbol Options › Export Type
 @msg	name is empty	o nome está vazio
 @msg	an action is already recording	uma ação já está sendo gravada
+@msg	an action is already playing	uma ação já está sendo reproduzida
+@msg	the action stopped playing: its document is no longer active	a ação parou: o documento dela não está mais ativo
+@msg	speed must be accelerated, step or pause	speed deve ser accelerated, step ou pause
+@msg	seconds must be a whole number from 1 to 60	seconds deve ser um número inteiro de 1 a 60
 @msg	no such function key	tecla de função inexistente
 @msg	no such color	cor inexistente
 @msg	{_1} cannot be used on Windows	{_1} não pode ser usado no Windows
@@ -5681,6 +5685,11 @@ axis	Y Axis	Eixo Y
 	Set Options	Opções do Conjunto
 	Action Options…	Opções da Ação…
 	Action Options	Opções da Ação
+	Playback Options…	Opções de Reprodução…
+	Playback Options	Opções de Reprodução
+	Accelerated	Acelerada
+	Step by Step	Passo a Passo
+	Pause For	Pausar Por
 	Rename Action	Renomear Ação
 	New Action…	Nova Ação…
 	New Action	Nova Ação

crates/ui-egui/src/i18n/ru.tsv

@@ -5200,6 +5200,10 @@ lighting	Light	Свет
 	Movie Clip	Видеоклип
 @msg	name is empty	имя пустое
 @msg	an action is already recording	действие уже записывается
+@msg	an action is already playing	действие уже воспроизводится
+@msg	the action stopped playing: its document is no longer active	воспроизведение действия остановлено: его документ больше не активен
+@msg	speed must be accelerated, step or pause	speed должен быть accelerated, step или pause
+@msg	seconds must be a whole number from 1 to 60	seconds должно быть целым числом от 1 до 60
 @msg	no such function key	такой функциональной клавиши нет
 @msg	no such color	такого цвета нет
 @msg	{_1} cannot be used on Windows	Сочетание {_1} нельзя использовать в Windows
@@ -5377,6 +5381,11 @@ axis	Y Axis	Ось Y
 	Set Options	Параметры набора
 	Action Options…	Параметры действия…
 	Action Options	Параметры действия
+	Playback Options…	Параметры воспроизведения…
+	Playback Options	Параметры воспроизведения
+	Accelerated	Ускоренно
+	Step by Step	Пошагово
+	Pause For	Пауза
 	Rename Action	Переименовать действие
 	New Action…	Новое действие…
 	New Action	Новое действие

crates/ui-egui/src/i18n/sv.tsv

@@ -5547,6 +5547,10 @@ theme	Appearance	Utseende
 	Movie Clip	Filmklipp
 @msg	name is empty	namnet är tomt
 @msg	an action is already recording	en åtgärd spelas redan in
+@msg	an action is already playing	en åtgärd spelas redan upp
+@msg	the action stopped playing: its document is no longer active	åtgärden stoppades: dess dokument är inte längre aktivt
+@msg	speed must be accelerated, step or pause	speed måste vara accelerated, step eller pause
+@msg	seconds must be a whole number from 1 to 60	seconds måste vara ett heltal från 1 till 60
 @msg	no such function key	funktionstangenten finns inte
 @msg	no such color	färgen finns inte
 @msg	{_1} cannot be used on Windows	{_1} kan inte användas i Windows
@@ -5789,6 +5793,11 @@ axis	Y Axis	Y-axel
 	Set Options	Alternativ för uppsättning
 	Action Options…	Alternativ för åtgärd…
 	Action Options	Alternativ för åtgärd
+	Playback Options…	Uppspelningsalternativ…
+	Playback Options	Uppspelningsalternativ
+	Accelerated	Accelererad
+	Step by Step	Steg för steg
+	Pause For	Paus i
 	Rename Action	Byt namn på åtgärd
 	New Action…	Ny åtgärd…
 	New Action	Ny åtgärd

crates/ui-egui/src/i18n/tr.tsv

@@ -5256,6 +5256,10 @@ theme	Appearance	Görünüm
 	Movie Clip	Film Klibi
 @msg	name is empty	isim boş
 @msg	an action is already recording	zaten bir eylem kaydediliyor
+@msg	an action is already playing	zaten bir eylem oynatılıyor
+@msg	the action stopped playing: its document is no longer active	eylemin oynatılması durdu: belgesi artık etkin değil
+@msg	speed must be accelerated, step or pause	speed accelerated, step veya pause olmalıdır
+@msg	seconds must be a whole number from 1 to 60	seconds 1 ile 60 arasında bir tam sayı olmalıdır
 @msg	no such function key	öyle bir işlev tuşu yok
 @msg	no such color	öyle bir renk yok
 @msg	{_1} cannot be used on Windows	{_1} Windows'ta kullanılamaz
@@ -5723,6 +5727,11 @@ axis	Y Axis	Y ekseni
 	Set Options	Set Seçenekleri
 	Action Options…	Eylem Seçenekleri…
 	Action Options	Eylem Seçenekleri
+	Playback Options…	Oynatma Seçenekleri…
+	Playback Options	Oynatma Seçenekleri
+	Accelerated	Hızlandırılmış
+	Step by Step	Adım Adım
+	Pause For	Duraklat
 	Rename Action	Eylemi Yeniden Adlandır
 	New Action…	Yeni Eylem…
 	New Action	Yeni Eylem

crates/ui-egui/src/i18n/uk.tsv

@@ -5185,6 +5185,10 @@ lighting	Light	Світло
 	Movie Clip	Кліп
 @msg	name is empty	ім’я порожнє
 @msg	an action is already recording	дія вже записується
+@msg	an action is already playing	дія вже відтворюється
+@msg	the action stopped playing: its document is no longer active	відтворення дії зупинено: її документ більше не активний
+@msg	speed must be accelerated, step or pause	speed має бути accelerated, step або pause
+@msg	seconds must be a whole number from 1 to 60	seconds має бути цілим числом від 1 до 60
 @msg	no such function key	такої функціональної клавіші немає
 @msg	no such color	такого кольору немає
 @msg	{_1} cannot be used on Windows	Сполучення {_1} не можна використовувати у Windows
@@ -5362,6 +5366,11 @@ axis	Y Axis	Вісь Y
 	Set Options	Параметри набору
 	Action Options…	Параметри дії…
 	Action Options	Параметри дії
+	Playback Options…	Параметри відтворення…
+	Playback Options	Параметри відтворення
+	Accelerated	Прискорено
+	Step by Step	Покроково
+	Pause For	Пауза
 	Rename Action	Перейменувати дію
 	New Action…	Нова дія…
 	New Action	Нова дія

crates/ui-egui/src/i18n/vi.tsv

@@ -5186,6 +5186,10 @@ theme	Appearance	Giao diện
 	Movie Clip	Clip phim
 @msg	name is empty	tên trống
 @msg	an action is already recording	đang ghi một hành động
+@msg	an action is already playing	đang phát một hành động
+@msg	the action stopped playing: its document is no longer active	hành động đã dừng phát: tài liệu của nó không còn hoạt động
+@msg	speed must be accelerated, step or pause	speed phải là accelerated, step hoặc pause
+@msg	seconds must be a whole number from 1 to 60	seconds phải là số nguyên từ 1 đến 60
 @msg	no such function key	không có phím chức năng như vậy
 @msg	no such color	không có màu như vậy
 @msg	{_1} cannot be used on Windows	không thể dùng {_1} trên Windows
@@ -5363,6 +5367,11 @@ axis	Y Axis	Trục Y
 	Set Options	Tùy chọn bộ
 	Action Options…	Tùy chọn hành động…
 	Action Options	Tùy chọn hành động
+	Playback Options…	Tùy chọn phát lại…
+	Playback Options	Tùy chọn phát lại
+	Accelerated	Tăng tốc
+	Step by Step	Từng bước
+	Pause For	Tạm dừng
 	Rename Action	Đổi tên hành động
 	New Action…	Hành động mới…
 	New Action	Hành động mới

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -5425,6 +5425,10 @@ lighting	Light	光源
 	Movie Clip	影片剪辑
 @msg	name is empty	名称为空
 @msg	an action is already recording	已在记录动作
+@msg	an action is already playing	已在播放动作
+@msg	the action stopped playing: its document is no longer active	动作已停止播放：其文档不再是现用文档
+@msg	speed must be accelerated, step or pause	speed 必须为 accelerated、step 或 pause
+@msg	seconds must be a whole number from 1 to 60	seconds 必须为 1 到 60 之间的整数
 @msg	no such function key	没有此功能键
 @msg	no such color	没有此颜色
 @msg	{_1} cannot be used on Windows	{_1} 在 Windows 上不能使用
@@ -5604,6 +5608,11 @@ axis	Y Axis	Y 轴
 	Set Options	组选项
 	Action Options…	动作选项…
 	Action Options	动作选项
+	Playback Options…	播放选项…
+	Playback Options	播放选项
+	Accelerated	加速
+	Step by Step	逐步
+	Pause For	暂停
 	Rename Action	重命名动作
 	New Action…	新建动作…
 	New Action	新建动作

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -5243,6 +5243,10 @@ lighting	Light	光源
 	Movie Clip	影片片段
 @msg	name is empty	名稱為空
 @msg	an action is already recording	已在錄製動作
+@msg	an action is already playing	已在播放動作
+@msg	the action stopped playing: its document is no longer active	動作已停止播放：其文件不再是作用中文件
+@msg	speed must be accelerated, step or pause	speed 必須為 accelerated、step 或 pause
+@msg	seconds must be a whole number from 1 to 60	seconds 必須為 1 到 60 之間的整數
 @msg	no such function key	沒有這個功能鍵
 @msg	no such color	沒有這個顏色
 @msg	{_1} cannot be used on Windows	{_1} 無法在 Windows 上使用
@@ -5400,6 +5404,11 @@ axis	Y Axis	Y 軸
 	Set Options	組選項
 	Action Options…	動作選項…
 	Action Options	動作選項
+	Playback Options…	播放選項…
+	Playback Options	播放選項
+	Accelerated	加速
+	Step by Step	逐步
+	Pause For	暫停
 	Rename Action	重新命名動作
 	New Action…	新增動作…
 	New Action	新增動作

crates/ui-egui/src/menus/run.rs

@@ -826,6 +826,7 @@ fn run_ui_part11(app: &mut VectorcraftApp, id: &str, p: &Value) -> Option<Result
         crate::panels::actions::NEW_ACTION => crate::panels::actions::new_action(app, p),
         crate::panels::actions::ACTION_OPTIONS => crate::panels::actions::action_options(app, p),
         crate::panels::actions::PLAY_ACTION => crate::panels::actions::play_action(app, p),
+        crate::panels::actions::PLAYBACK_OPTIONS => crate::panels::actions::playback_options(app, p),
         crate::panels::actions::START_RECORDING => crate::panels::actions::record(app, p),
         crate::panels::actions::STOP_RECORDING => crate::panels::actions::stop(app, p),
         "ui.batchDialog" => {

crates/ui-egui/src/menus/ui_commands.rs

@@ -1239,7 +1239,13 @@ pub const UI_COMMANDS: &[(&str, &str, &str, &str)] = &[
         crate::panels::actions::PLAY_ACTION,
         "Play Action",
         "",
-        "{action: name, set?: name} play the Actions panel's action named action as one undoable batch; set names the set to look in (default: every set). A name no action has, or one that more than one action in the sets looked in has, is an error and nothing plays → what command.batch returns",
+        "{action: name, set?: name} play the Actions panel's action named action at the speed ui.action.playbackOptions sets; set names the set to look in (default: every set). Accelerated plays it as one undoable batch → what command.batch returns. Step by Step and Pause For play its first step now and the others one at a time, each its own undo step, until the last, ui.action.stop, or a step that comes due while a different document is active than after the step before → {results: [the first step's result], pending: the steps left}. A name no action has, or one that more than one action in the sets looked in has, or an action played while another is still playing step by step or with pauses, is an error and nothing plays",
+    ),
+    (
+        crate::panels::actions::PLAYBACK_OPTIONS,
+        "Playback Options",
+        "",
+        "{speed?: accelerated|step|pause, seconds?: 1-60} set how the Actions panel plays actions: accelerated (the default) plays every step at once, step plays one step at a time and draws the window after each, and pause waits seconds (a whole number, 1 to 60, VectorCraft's own range) between steps. A param left out keeps its value; the setting is kept with the UI preferences. Any other speed or seconds is an error and changes nothing. The panel menu's Playback Options… (dialog `actionPlayback` with speed and seconds) runs this on OK → {speed, seconds}",
     ),
     (
         crate::panels::actions::START_RECORDING,
@@ -1251,7 +1257,7 @@ pub const UI_COMMANDS: &[(&str, &str, &str, &str)] = &[
         crate::panels::actions::STOP_RECORDING,
         "Stop Playing/Recording",
         "",
-        "{} end the Actions panel's recording and keep its steps, in the action ui.action.new made for it, else in a new action after the last action of its set, as the panel's Stop Playing/Recording button does. With nothing recording it changes nothing → {stopped}",
+        "{} end the Actions panel's recording and keep its steps, in the action ui.action.new made for it, else in a new action after the last action of its set, as the panel's Stop Playing/Recording button does. It also ends an action playing step by step or with pauses: the steps played stay and the rest do not run. With nothing recording or playing it changes nothing → {stopped}",
     ),
     (
         "ui.batchDialog",

crates/ui-egui/src/panels/actions.rs

@@ -61,12 +61,18 @@ impl Action {
         }
     }
 
+    /// The included steps as `command.batch` takes them. A recorded `command.batch` step (an action
+    /// played, or a panel operation that runs as one batch, while recording) gives its own steps,
+    /// since batches do not nest.
     pub(crate) fn included_commands(&self) -> Vec<Value> {
         self.steps
             .iter()
             .enumerate()
             .filter(|(i, _)| !self.excluded_steps.contains(i))
-            .map(|(_, (command, params))| json!({"command": command, "params": params}))
+            .flat_map(|(_, (command, params))| match params.get("commands").and_then(Value::as_array) {
+                Some(steps) if command == "command.batch" => steps.clone(),
+                _ => vec![json!({"command": command, "params": params})],
+            })
             .collect()
     }
 }
@@ -203,14 +209,212 @@ pub fn default_sets() -> Vec<ActionSet> {
     )]
 }
 
-/// Run an action as a single undoable batch.
+/// Plays an action at the speed [`UiState::action_playback`](crate::UiState::action_playback) sets.
+/// Accelerated runs every included step at once as a single undoable batch → what `command.batch`
+/// returns. Step by Step and Pause For run the first step now, each as its own undo step, and leave
+/// the rest to [`tick_playback`] → {results: [the first step's result], pending: the steps left}.
+/// While a paced playback is in progress, another action does not play.
 pub fn play(app: &mut VectorcraftApp, set: usize, idx: usize) -> Result<Value, String> {
     let Some(a) = app.ui.action_sets.get(set).and_then(|s| s.actions.get(idx)).cloned() else { return Err("no such action".into()) };
     let commands = a.included_commands();
     if commands.is_empty() {
         return Err("the action has no included steps".into());
     }
-    app.run("command.batch", json!({"label": a.name, "commands": commands}))
+    if app.ui.action_playing.is_some() {
+        return Err("an action is already playing".into());
+    }
+    let options = app.ui.action_playback;
+    if options.speed == PlaybackSpeed::Accelerated {
+        return app.run("command.batch", json!({"label": a.name, "commands": commands}));
+    }
+    let mut steps: std::collections::VecDeque<Value> = commands.into();
+    let Some(first) = steps.pop_front() else { return Err("the action has no included steps".into()) };
+    let result = play_step(app, &a.name, first)?;
+    let pending = steps.len();
+    if pending > 0 {
+        let hold = options.speed == PlaybackSpeed::Step;
+        let doc = active_doc(app);
+        let played_in = app.tick_iteration.filter(|&t| t == app.host_iteration);
+        app.ui.action_playing = Some(Playing { label: a.name, steps, options, next_at: None, hold, doc, played_in });
+        if let Some(ctx) = &app.ui_ctx {
+            ctx.request_repaint();
+        }
+    }
+    Ok(json!({"results": [result], "pending": pending}))
+}
+
+/// Runs one step of a paced playback as its own undo step, named `label` → the step's result.
+fn play_step(app: &mut VectorcraftApp, label: &str, step: Value) -> Result<Value, String> {
+    let r = app.run("command.batch", json!({"label": label, "commands": [step]}))?;
+    Ok(r.get("results").and_then(|r| r.get(0)).cloned().unwrap_or(Value::Null))
+}
+
+/// The speed actions play at (Actions panel menu › Playback Options…).
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum PlaybackSpeed {
+    /// Every included step at once.
+    #[default]
+    Accelerated,
+    /// One step at a time, with the window drawn after each step before the next step runs.
+    Step,
+    /// [`PlaybackOptions::seconds`] between steps.
+    Pause,
+}
+
+/// The pause between steps that Pause For takes, in whole seconds: VectorCraft's own range.
+pub const PAUSE_SECONDS: std::ops::RangeInclusive<u32> = 1..=60;
+
+/// How actions play, kept with the UI preferences.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct PlaybackOptions {
+    pub speed: PlaybackSpeed,
+    /// The pause between steps with [`PlaybackSpeed::Pause`], within [`PAUSE_SECONDS`]. It is kept
+    /// while another speed is chosen.
+    pub seconds: u32,
+}
+
+impl Default for PlaybackOptions {
+    fn default() -> Self {
+        Self { speed: PlaybackSpeed::Accelerated, seconds: *PAUSE_SECONDS.start() }
+    }
+}
+
+/// Reads saved [`PlaybackOptions`]: a value that is not a valid one loads as the default.
+pub fn deserialize_playback<'de, D: serde::Deserializer<'de>>(d: D) -> Result<PlaybackOptions, D::Error> {
+    let v = <Value as serde::Deserialize>::deserialize(d)?;
+    Ok(serde_json::from_value::<PlaybackOptions>(v).ok().filter(|o| PAUSE_SECONDS.contains(&o.seconds)).unwrap_or_default())
+}
+
+/// A paced playback in progress: the steps still to run.
+#[derive(Clone, Debug)]
+pub struct Playing {
+    /// The action's name, which names each step's undo step.
+    label: String,
+    steps: std::collections::VecDeque<Value>,
+    /// The options the action started playing with.
+    options: PlaybackOptions,
+    /// With Pause For, when the next step runs (seconds on the app's clock); none until the frame
+    /// after each step, which starts the pause before the next one.
+    next_at: Option<f64>,
+    /// With Step by Step, set after each step until the window shows a frame drawn after it
+    /// ([`playback_drawn`]): no step runs while it is set, so the window shows each step's result
+    /// before the next one runs, also when Play in the panel ran after the canvas drew and while the
+    /// window is minimized or covered.
+    hold: bool,
+    /// The [`uid`](vectorcraft_engine::DocState::uid) of the document that was active after the
+    /// last step played, if any.
+    doc: Option<u64>,
+    /// The host iteration in which Play ran the first step, when that iteration's [`tick`] had
+    /// already begun (a control request, or the UI pass after it): the pause before the second step
+    /// starts in a later iteration.
+    ///
+    /// [`tick`]: VectorcraftApp::tick
+    played_in: Option<u64>,
+}
+
+fn active_doc(app: &VectorcraftApp) -> Option<u64> {
+    app.session.active().map(|d| d.uid)
+}
+
+/// Runs the next step of the paced playback in progress when it is due at `now` (seconds on the
+/// app's clock): with Step by Step once the window has shown a frame drawn after the step before
+/// ([`playback_drawn`]), so it shows each step before the next one runs; with Pause For once
+/// the pause has passed, which starts in the frame after the step before, so a slow step or a late
+/// frame does not shorten it. A step that fails ends the playback and shows its error. When a step
+/// is due and the active document is not the one that was active after the last step (another
+/// document was made active, or that one was closed), the playback ends with a status and the rest
+/// do not run. → the seconds until the window should draw again while playback goes on (none while
+/// Step by Step waits for a UI pass, which asks for the next frame itself)
+pub fn tick_playback(app: &mut VectorcraftApp, now: f64) -> Option<f64> {
+    let doc = active_doc(app);
+    let playing = app.ui.action_playing.as_mut()?;
+    if playing.hold {
+        return None;
+    }
+    let pause = f64::from(playing.options.seconds);
+    if playing.options.speed == PlaybackSpeed::Pause {
+        if playing.next_at.is_none() && playing.played_in == Some(app.host_iteration) {
+            return Some(0.0);
+        }
+        let due = *playing.next_at.get_or_insert(now + pause);
+        if now < due {
+            return Some(due - now);
+        }
+    }
+    if playing.doc != doc {
+        app.ui.action_playing = None;
+        app.status("the action stopped playing: its document is no longer active");
+        return None;
+    }
+    let Some(step) = playing.steps.pop_front() else {
+        app.ui.action_playing = None;
+        return None;
+    };
+    let label = playing.label.clone();
+    if playing.steps.is_empty() {
+        app.ui.action_playing = None;
+    }
+    if let Err(e) = play_step(app, &label, step) {
+        app.ui.action_playing = None;
+        app.status(e);
+        return None;
+    }
+    let doc = active_doc(app);
+    let playing = app.ui.action_playing.as_mut()?;
+    // A step of the action may open, close or switch documents itself.
+    playing.doc = doc;
+    // With Pause For, the next frame starts the next pause.
+    playing.next_at = None;
+    playing.hold = playing.options.speed == PlaybackSpeed::Step;
+    Some(0.0)
+}
+
+/// Whether a Step by Step playback waits for a frame that shows its last step ([`playback_drawn`]).
+pub fn playback_held(app: &VectorcraftApp) -> bool {
+    app.ui.action_playing.as_ref().is_some_and(|p| p.hold)
+}
+
+/// Called after a UI pass that the window shows, when [`playback_held`] was true as the pass began:
+/// the Step by Step playback runs its next step in the frame after this one, which it asks for.
+pub fn playback_drawn(app: &mut VectorcraftApp) {
+    if let Some(playing) = app.ui.action_playing.as_mut().filter(|p| p.hold) {
+        playing.hold = false;
+        if let Some(ctx) = &app.ui_ctx {
+            ctx.request_repaint();
+        }
+    }
+}
+
+/// The command behind Playback Options… ([`playback_options`]).
+pub const PLAYBACK_OPTIONS: &str = "ui.action.playbackOptions";
+
+/// `ui.action.playbackOptions {speed?, seconds?}`: sets how actions play. `speed` is
+/// `accelerated` (every step at once, the default), `step` (one step at a time, the window drawn
+/// after each) or `pause` (`seconds` between steps); `seconds` is a whole number in
+/// [`PAUSE_SECONDS`]. A param left out keeps its value. Any other value is an error, and then
+/// nothing changes. An action already playing keeps its speed. → {speed, seconds}
+pub fn playback_options(app: &mut VectorcraftApp, p: &Value) -> Result<Value, String> {
+    let current = app.ui.action_playback;
+    let speed = match p.get("speed") {
+        None => current.speed,
+        Some(v) => match v.as_str() {
+            Some("accelerated") => PlaybackSpeed::Accelerated,
+            Some("step") => PlaybackSpeed::Step,
+            Some("pause") => PlaybackSpeed::Pause,
+            _ => return Err("speed must be accelerated, step or pause".into()),
+        },
+    };
+    let seconds = match p.get("seconds") {
+        None => current.seconds,
+        Some(v) => v
+            .as_u64()
+            .and_then(|s| u32::try_from(s).ok())
+            .filter(|s| PAUSE_SECONDS.contains(s))
+            .ok_or("seconds must be a whole number from 1 to 60")?,
+    };
+    app.ui.action_playback = PlaybackOptions { speed, seconds };
+    Ok(json!({"speed": speed, "seconds": seconds}))
 }
 
 /// The command behind the Actions panel's set, action and step checkmarks.
@@ -380,10 +584,11 @@ pub fn action_options(app: &mut VectorcraftApp, p: &Value) -> Result<Value, Stri
 /// The command that plays an action by its name ([`play_action`]).
 pub const PLAY_ACTION: &str = "ui.action.play";
 
-/// `ui.action.play {action, set?}`: plays the action named `action` as one undoable batch, as
-/// Play Current Selection does. `set` names the set to look in (default: every set); a `set` that
-/// is not a string is an error. A name that no action has is an error, and so is a name that more
-/// than one action in the sets looked in has: then nothing plays. → what `command.batch` returns
+/// `ui.action.play {action, set?}`: plays the action named `action` at the Playback Options speed,
+/// as Play Current Selection does ([`play`]). `set` names the set to look in (default: every set); a
+/// `set` that is not a string is an error. A name that no action has is an error, and so is a name
+/// that more than one action in the sets looked in has: then nothing plays. → what [`play`] returns:
+/// at Accelerated, what `command.batch` returns; at Step by Step and Pause For, {results, pending}
 pub fn play_action(app: &mut VectorcraftApp, p: &Value) -> Result<Value, String> {
     let name = p.get("action").and_then(Value::as_str).ok_or("no such action")?;
     let in_set = match p.get("set") {
@@ -444,11 +649,14 @@ pub fn record(app: &mut VectorcraftApp, p: &Value) -> Result<Value, String> {
 
 /// `ui.action.stop {}`: ends the recording in progress and keeps its steps, in the action New
 /// Action made for it, else in a new action after the last action of its set, as the bottom bar's
-/// Stop Playing/Recording does. With nothing recording it changes nothing. → {stopped}
+/// Stop Playing/Recording does. It also ends a playback at Step by Step or Pause For: the steps
+/// already played stay, and the rest do not run. With nothing recording or playing it changes
+/// nothing. → {stopped}
 pub fn stop(app: &mut VectorcraftApp, _: &Value) -> Result<Value, String> {
-    let stopped = app.ui.recording.is_some();
+    let playing = app.ui.action_playing.take().is_some();
+    let recording = app.ui.recording.is_some();
     stop_recording(app);
-    Ok(json!({ "stopped": stopped }))
+    Ok(json!({ "stopped": recording || playing }))
 }
 
 /// The command that `chord` runs under `km`, pressed once or pressed twice.
@@ -801,6 +1009,9 @@ pub fn menu(app: &mut VectorcraftApp, ui: &mut egui::Ui) {
     {
         crate::dialogs::action_set_options::open_action(app, s, a);
     }
+    if widgets::menu_item(ui, tl!("Playback Options…"), true, false) {
+        crate::dialogs::action_playback::open(app);
+    }
     ui.separator();
     // As commands, so a file dialog shown off the UI thread saves or loads when it answers.
     // Save Actions… names the current set by its id, so a file dialog that answers later saves that set.
@@ -2662,4 +2873,402 @@ mod tests {
             "the command keeps its shortcut"
         );
     }
+
+    /// A document with one rectangle selected and the set "Moves" with one action that moves it
+    /// right three times, by 1, 2 and 4 pt → (the app, the rectangle's left edge as it moves).
+    fn app_with_three_moves() -> (VectorcraftApp, impl Fn(&VectorcraftApp) -> f64) {
+        let mut app = VectorcraftApp::new(Session::new(), Default::default());
+        app.run("file.new", json!({"width": 200, "height": 100})).unwrap();
+        let id = vectorcraft_doc::NodeId(
+            app.run("shape.rectangle", json!({"x": 10, "y": 10, "width": 20, "height": 20})).unwrap()["id"].as_u64().unwrap(),
+        );
+        app.run("select.set", json!({"ids": [id.0]})).unwrap();
+        let step = |dx: u32| ("object.move".to_string(), json!({"dx": dx, "dy": 0}));
+        app.ui.action_sets = vec![ActionSet::new("Moves", vec![Action::new("Three Moves", vec![step(1), step(2), step(4)])])];
+        let x = move |app: &VectorcraftApp| app.session.active().unwrap().doc.node(id).unwrap().geometric_bounds().unwrap().x0 - 10.0;
+        (app, x)
+    }
+
+    fn undo_steps(app: &VectorcraftApp) -> usize {
+        app.session.active().unwrap().history.undo.len()
+    }
+
+    /// One frame of a shown window at `now`: the logic pass, then a UI pass that draws → what the
+    /// logic pass's [`tick_playback`] returns.
+    fn frame(app: &mut VectorcraftApp, now: f64) -> Option<f64> {
+        let wait = tick_playback(app, now);
+        playback_drawn(app);
+        wait
+    }
+
+    /// Draws frames until the playback in progress ends (at most 20).
+    fn play_out(app: &mut VectorcraftApp) {
+        for _ in 0..20 {
+            if app.ui.action_playing.is_none() {
+                return;
+            }
+            frame(app, 0.0);
+        }
+        panic!("the playback did not end");
+    }
+
+    #[test]
+    fn playback_options_sets_each_speed_and_refuses_bad_values() {
+        let mut app = VectorcraftApp::new(Session::new(), Default::default());
+        assert_eq!(app.ui.action_playback, PlaybackOptions { speed: PlaybackSpeed::Accelerated, seconds: 1 }, "Accelerated is the default");
+        assert_eq!(app.run(PLAYBACK_OPTIONS, json!({"speed": "step"})).unwrap(), json!({"speed": "step", "seconds": 1}));
+        assert_eq!(app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 2})).unwrap(), json!({"speed": "pause", "seconds": 2}));
+        assert_eq!(
+            app.run(PLAYBACK_OPTIONS, json!({"speed": "accelerated"})).unwrap(),
+            json!({"speed": "accelerated", "seconds": 2}),
+            "seconds kept"
+        );
+        assert_eq!(app.run(PLAYBACK_OPTIONS, json!({"seconds": 60})).unwrap(), json!({"speed": "accelerated", "seconds": 60}), "speed kept");
+        let kept = app.ui.action_playback;
+        for bad in [json!({"speed": "fast"}), json!({"speed": null}), json!({"speed": 1})] {
+            assert_eq!(app.run(PLAYBACK_OPTIONS, bad.clone()).unwrap_err(), "speed must be accelerated, step or pause", "{bad}");
+        }
+        for bad in [json!(0), json!(61), json!(2.5), json!(-1), json!("2"), json!(null)] {
+            let p = json!({"speed": "pause", "seconds": bad});
+            assert_eq!(app.run(PLAYBACK_OPTIONS, p).unwrap_err(), "seconds must be a whole number from 1 to 60", "{bad}");
+        }
+        assert_eq!(app.ui.action_playback, kept, "a refused value changes nothing");
+        // Kept with the UI preferences; a saved value that is not valid loads as the default.
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 5})).unwrap();
+        let mut saved = serde_json::to_value(&app.ui).unwrap();
+        let ui = serde_json::from_value::<crate::UiState>(saved.clone()).unwrap();
+        assert_eq!(ui.action_playback, PlaybackOptions { speed: PlaybackSpeed::Pause, seconds: 5 });
+        for bad in [json!({"speed": "pause", "seconds": 0}), json!({"speed": "slow", "seconds": 5}), json!("step")] {
+            saved["action_playback"] = bad;
+            assert_eq!(serde_json::from_value::<crate::UiState>(saved.clone()).unwrap().action_playback, PlaybackOptions::default());
+        }
+    }
+
+    #[test]
+    fn the_playback_options_dialog_sets_the_speed_and_pause() {
+        let mut app = VectorcraftApp::new(Session::new(), Default::default());
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "step", "seconds": 3})).unwrap();
+        crate::dialogs::action_playback::open(&mut app);
+        let d = app.ui.dialog.as_mut().unwrap();
+        assert_eq!((d.kind.as_str(), d.str("speed"), d.fields["seconds"].clone()), ("actionPlayback", "step".to_string(), json!(3)));
+        d.fields.insert("speed".into(), json!("pause"));
+        d.fields.insert("seconds".into(), json!(4));
+        crate::dialogs::confirm(&mut app).unwrap();
+        assert!(app.ui.dialog.is_none());
+        assert_eq!(app.ui.action_playback, PlaybackOptions { speed: PlaybackSpeed::Pause, seconds: 4 });
+    }
+
+    #[test]
+    fn accelerated_playback_plays_every_step_as_one_undo_step() {
+        let (mut app, x) = app_with_three_moves();
+        let before = undo_steps(&app);
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(x(&app), 7.0);
+        assert_eq!(undo_steps(&app), before + 1);
+        assert!(app.ui.action_playing.is_none());
+        assert_eq!(tick_playback(&mut app, 0.0), None, "nothing waits for a frame");
+    }
+
+    #[test]
+    fn step_by_step_plays_one_step_per_frame_and_redraws_between_steps() {
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "step"})).unwrap();
+        let before = undo_steps(&app);
+        assert_eq!(play(&mut app, 0, 0).unwrap()["pending"], json!(2));
+        assert_eq!(x(&app), 1.0, "the first step runs at once");
+        assert_eq!(frame(&mut app, 0.0), None, "the frame after Play draws the first step");
+        assert_eq!(x(&app), 1.0, "and runs no step, even when Play ran after the canvas drew");
+        assert_eq!(frame(&mut app, 0.0), Some(0.0), "the window draws again before the next step");
+        assert_eq!(x(&app), 3.0, "one more step in this frame");
+        assert_eq!(frame(&mut app, 0.0), None, "the last step ends the playback");
+        assert_eq!(x(&app), 7.0);
+        assert!(app.ui.action_playing.is_none());
+        assert_eq!(frame(&mut app, 0.0), None);
+        assert_eq!(x(&app), 7.0);
+        assert_eq!(undo_steps(&app), before + 3, "each step is its own undo step");
+        assert_eq!(app.session.active().unwrap().history.undo.last().unwrap().label, "Three Moves");
+    }
+
+    #[test]
+    fn step_by_step_runs_no_step_until_the_window_draws_the_one_before() {
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "step"})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        // A hidden window runs logic passes only, which draw nothing.
+        for _ in 0..3 {
+            assert_eq!(tick_playback(&mut app, 0.0), None, "no step runs and no frame is asked for");
+        }
+        assert_eq!(x(&app), 1.0);
+        playback_drawn(&mut app);
+        assert_eq!(tick_playback(&mut app, 0.0), Some(0.0));
+        assert_eq!(x(&app), 3.0, "the step after a drawn frame runs");
+        for _ in 0..3 {
+            assert_eq!(tick_playback(&mut app, 0.0), None);
+        }
+        assert_eq!(x(&app), 3.0, "the next step waits until the window draws this one");
+        playback_drawn(&mut app);
+        assert_eq!(tick_playback(&mut app, 0.0), None, "the last step ends the playback");
+        assert_eq!(x(&app), 7.0);
+    }
+
+    #[test]
+    fn step_by_step_waits_while_the_window_is_hidden() {
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "step"})).unwrap();
+        let ctx = egui::Context::default();
+        // One host iteration: `tick`, then a UI pass, in a shown or an occluded window.
+        let frame = |app: &mut VectorcraftApp, hidden: bool| {
+            let mut raw =
+                egui::RawInput { screen_rect: Some(egui::Rect::from_min_size(egui::Pos2::ZERO, egui::vec2(1200.0, 800.0))), ..Default::default() };
+            if hidden {
+                raw.viewports.entry(egui::ViewportId::ROOT).or_default().occluded = Some(true);
+            }
+            app.begin_host_iteration();
+            let mut out = ctx.run_ui(raw, |ui| {
+                app.tick(ui.ctx());
+                app.ui(ui);
+            });
+            out.textures_delta.clear();
+        };
+        // Fonts install on the first pass and are ready on the second.
+        frame(&mut app, false);
+        frame(&mut app, false);
+        play(&mut app, 0, 0).unwrap();
+        for _ in 0..3 {
+            frame(&mut app, true);
+        }
+        assert_eq!(x(&app), 1.0, "no step runs while the window is hidden, even in a UI pass");
+        frame(&mut app, false);
+        assert_eq!(x(&app), 1.0, "the shown frame draws the first step");
+        frame(&mut app, true);
+        assert_eq!(x(&app), 3.0, "the first step was shown, so the second runs");
+        for _ in 0..3 {
+            frame(&mut app, true);
+        }
+        assert_eq!(x(&app), 3.0, "the third step waits until the window shows the second");
+        frame(&mut app, false);
+        assert_eq!(x(&app), 3.0, "the shown frame draws the second step");
+        frame(&mut app, false);
+        assert_eq!(x(&app), 7.0);
+        assert!(app.ui.action_playing.is_none());
+    }
+
+    #[test]
+    fn pause_for_waits_the_seconds_between_steps() {
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 2})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(x(&app), 1.0);
+        assert_eq!(tick_playback(&mut app, 10.0), Some(2.0), "the pause starts in the frame after the first step");
+        assert_eq!(tick_playback(&mut app, 11.5), Some(0.5));
+        assert_eq!(x(&app), 1.0, "nothing runs before the pause has passed");
+        assert_eq!(tick_playback(&mut app, 12.0), Some(0.0), "the next frame comes promptly");
+        assert_eq!(x(&app), 3.0, "the second step runs after 2 s");
+        assert_eq!(tick_playback(&mut app, 12.0), Some(2.0), "and starts the next pause");
+        assert!(tick_playback(&mut app, 13.9).is_some_and(|wait| (wait - 0.1).abs() < 1e-9));
+        assert_eq!(x(&app), 3.0);
+        assert_eq!(tick_playback(&mut app, 14.0), None);
+        assert_eq!(x(&app), 7.0, "the third step runs 2 s after the second");
+        assert!(app.ui.action_playing.is_none());
+    }
+
+    #[test]
+    fn pause_for_starts_each_pause_in_the_frame_after_the_step() {
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 2})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(tick_playback(&mut app, 0.0), Some(2.0));
+        assert!(tick_playback(&mut app, 2.0).is_some());
+        assert_eq!(x(&app), 3.0, "the second step runs");
+        // The next frame comes later than the pause, for example after a slow step.
+        assert_eq!(tick_playback(&mut app, 9.0), Some(2.0), "the pause starts in this frame");
+        assert_eq!(x(&app), 3.0, "no step runs without a pause before it");
+        assert_eq!(tick_playback(&mut app, 11.0), None);
+        assert_eq!(x(&app), 7.0, "the third step runs 2 s after the frame that started the pause");
+    }
+
+    #[test]
+    fn stop_ends_a_paced_playback_and_another_action_waits_for_it() {
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 1})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(play(&mut app, 0, 0).unwrap_err(), "an action is already playing");
+        assert_eq!(app.run(PLAY_ACTION, json!({"action": "Three Moves"})).unwrap_err(), "an action is already playing");
+        assert_eq!(x(&app), 1.0);
+        assert_eq!(app.run(STOP_RECORDING, json!({})).unwrap(), json!({"stopped": true}));
+        assert_eq!(tick_playback(&mut app, 100.0), None);
+        assert_eq!(x(&app), 1.0, "the steps after Stop do not run; the one played stays");
+        assert_eq!(app.run(STOP_RECORDING, json!({})).unwrap(), json!({"stopped": false}));
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(x(&app), 2.0, "an action plays again after Stop");
+    }
+
+    #[test]
+    fn control_requests_come_before_the_step_that_is_due() {
+        let ctx = egui::Context::default();
+        // One host iteration's `tick` at `now`.
+        let tick = |app: &mut VectorcraftApp, now: f64| {
+            app.now_override = Some(now);
+            app.begin_host_iteration();
+            let mut out = ctx.run_ui(egui::RawInput::default(), |ui| app.tick(ui.ctx()));
+            out.textures_delta.clear();
+        };
+        // The same, with `method` and `params` queued on the control channel → its reply.
+        let iteration =
+            |app: &mut VectorcraftApp, tx: &std::sync::mpsc::Sender<crate::control::ControlRequest>, now: f64, method: &str, params: Value| {
+                let (req, reply) = crate::control::ControlRequest::new(method, params);
+                tx.send(req).unwrap();
+                tick(app, now);
+                reply.try_recv().unwrap()
+            };
+        // Stop: the step that is due does not run.
+        let (app, x) = app_with_three_moves();
+        let (tx, rx) = std::sync::mpsc::channel();
+        let mut app = app.with_control(rx);
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 1})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(tick_playback(&mut app, 0.0), Some(1.0));
+        let r = iteration(&mut app, &tx, 5.0, "engine.execute", json!({"command": STOP_RECORDING}));
+        assert_eq!(r["result"], json!({"stopped": true}), "{r}");
+        assert!(app.ui.action_playing.is_none());
+        assert_eq!(x(&app), 1.0, "the step that was due did not run");
+        // A switch to another document: the playback ends, and the step does not run in the first one.
+        let (app, x) = app_with_three_moves();
+        let (tx, rx) = std::sync::mpsc::channel();
+        let mut app = app.with_control(rx);
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 1})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(tick_playback(&mut app, 0.0), Some(1.0));
+        let r = iteration(&mut app, &tx, 5.0, "engine.execute", json!({"command": "file.new", "params": {"width": 50, "height": 50}}));
+        assert_eq!(r["ok"], true, "{r}");
+        assert!(app.ui.action_playing.is_none(), "the playback ends in the same iteration");
+        assert_eq!(app.ui.status, "the action stopped playing: its document is no longer active");
+        app.run("document.activate", json!({"index": 0})).unwrap();
+        assert_eq!(x(&app), 1.0, "the step that was due did not run in the first document");
+        // Play: the pause after the first step starts in the next iteration.
+        let (app, x) = app_with_three_moves();
+        let (tx, rx) = std::sync::mpsc::channel();
+        let mut app = app.with_control(rx);
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 1})).unwrap();
+        let r = iteration(&mut app, &tx, 0.0, "engine.execute", json!({"command": PLAY_ACTION, "params": {"action": "Three Moves"}}));
+        assert_eq!(r["result"]["pending"], json!(2), "{r}");
+        assert_eq!(x(&app), 1.0);
+        tick(&mut app, 0.5);
+        tick(&mut app, 1.0);
+        assert_eq!(x(&app), 1.0, "the pause started at 0.5");
+        tick(&mut app, 1.5);
+        assert_eq!(x(&app), 3.0);
+    }
+
+    #[test]
+    fn an_action_recorded_while_another_plays_plays_its_steps() {
+        let (mut app, x) = app_with_three_moves();
+        // Accelerated: the recording gets the played action as one batch step.
+        app.run(START_RECORDING, json!({"set": 0})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        app.run(STOP_RECORDING, json!({})).unwrap();
+        assert_eq!(app.ui.action_sets[0].actions[1].steps.iter().map(|s| s.0.as_str()).collect::<Vec<_>>(), ["command.batch"]);
+        assert_eq!(x(&app), 7.0);
+        play(&mut app, 0, 1).unwrap();
+        assert_eq!(x(&app), 14.0, "the batch step plays its moves");
+        // Step by Step: recording begins after the first step, and gets each later step as a batch.
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "step"})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        app.run(START_RECORDING, json!({"set": 0})).unwrap();
+        play_out(&mut app);
+        app.run(STOP_RECORDING, json!({})).unwrap();
+        assert_eq!(x(&app), 21.0);
+        assert_eq!(app.ui.action_sets[0].actions[2].steps.len(), 2);
+        play(&mut app, 0, 2).unwrap();
+        play_out(&mut app);
+        assert_eq!(x(&app), 27.0, "paced: the recorded batches play the second and third moves");
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "accelerated"})).unwrap();
+        play(&mut app, 0, 2).unwrap();
+        assert_eq!(x(&app), 33.0, "accelerated: the recorded batches play inside the action's batch");
+    }
+
+    #[test]
+    fn a_paced_playback_ends_when_another_document_becomes_active() {
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 1})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(tick_playback(&mut app, 0.0), Some(1.0));
+        app.run("file.new", json!({"width": 50, "height": 50})).unwrap();
+        assert_eq!(tick_playback(&mut app, 0.5), Some(0.5), "nothing ends before the next step is due");
+        app.run("document.activate", json!({"index": 0})).unwrap();
+        assert_eq!(tick_playback(&mut app, 1.0), Some(0.0));
+        assert_eq!(x(&app), 3.0, "the document is active again when the step is due, so it runs");
+        app.run("document.activate", json!({"index": 1})).unwrap();
+        let other = app.session.active().unwrap().doc.clone();
+        assert_eq!(tick_playback(&mut app, 5.0), Some(1.0), "the next pause starts");
+        assert_eq!(tick_playback(&mut app, 6.0), None, "the playback ends");
+        assert!(app.ui.action_playing.is_none());
+        assert_eq!(app.ui.status, "the action stopped playing: its document is no longer active");
+        assert!(std::sync::Arc::ptr_eq(&app.session.active().unwrap().doc, &other), "no step ran in the other document");
+        app.run("document.activate", json!({"index": 0})).unwrap();
+        assert_eq!(tick_playback(&mut app, 10.0), None);
+        assert_eq!(x(&app), 3.0, "the rest of the steps do not run in the first document either");
+        // A step that makes another document active itself does not end the playback.
+        app.ui.action_sets[0].actions[0].steps.insert(0, ("document.activate".into(), json!({"index": 0})));
+        app.run("document.activate", json!({"index": 1})).unwrap();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "step"})).unwrap();
+        app.ui.status.clear();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(frame(&mut app, 0.0), None);
+        play_out(&mut app);
+        assert_ne!(app.ui.status, "the action stopped playing: its document is no longer active");
+        assert_eq!(x(&app), 10.0, "the moves after the step ran in the document it made active");
+    }
+
+    #[test]
+    fn closing_the_playing_document_ends_a_paced_playback() {
+        let stopped = "the action stopped playing: its document is no longer active";
+        // File › Close with `p`, answering Don't Save for the modified document.
+        let close = |app: &mut VectorcraftApp, p: Value| {
+            assert_eq!(app.run("file.close", p).unwrap(), json!({"pending": crate::unsaved::KIND}));
+            app.ui.dialog.as_mut().unwrap().fields.insert("discard".into(), json!(true));
+            crate::unsaved::confirm(app).unwrap();
+        };
+        // Step by Step, the only document closed: no document is active when the next step is due.
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "step"})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(x(&app), 1.0);
+        close(&mut app, json!({}));
+        assert!(app.session.active().is_none());
+        assert_eq!(frame(&mut app, 0.0), None, "the frame after Play draws");
+        assert_eq!(frame(&mut app, 0.0), None, "the next step is due, and the playback ends");
+        assert!(app.ui.action_playing.is_none());
+        assert_eq!(app.ui.status, stopped);
+        // Pause For, another document left active: no later step runs in it.
+        let (mut app, x) = app_with_three_moves();
+        app.run("file.new", json!({"width": 50, "height": 50})).unwrap();
+        let other = app.session.active().unwrap().doc.clone();
+        app.run("document.activate", json!({"index": 0})).unwrap();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "pause", "seconds": 1})).unwrap();
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(x(&app), 1.0);
+        assert_eq!(tick_playback(&mut app, 0.0), Some(1.0));
+        close(&mut app, json!({"index": 0}));
+        assert!(std::sync::Arc::ptr_eq(&app.session.active().unwrap().doc, &other));
+        assert_eq!(tick_playback(&mut app, 1.0), None, "the playback ends when the next step is due");
+        assert!(app.ui.action_playing.is_none());
+        assert_eq!(app.ui.status, stopped);
+        assert_eq!(tick_playback(&mut app, 10.0), None);
+        assert!(std::sync::Arc::ptr_eq(&app.session.active().unwrap().doc, &other), "no step ran in the document left open");
+    }
+
+    #[test]
+    fn a_failing_step_ends_a_paced_playback_with_its_error() {
+        let (mut app, x) = app_with_three_moves();
+        app.run(PLAYBACK_OPTIONS, json!({"speed": "step"})).unwrap();
+        app.ui.action_sets[0].actions[0].steps[1] = ("no.such.command".into(), json!({}));
+        play(&mut app, 0, 0).unwrap();
+        assert_eq!(frame(&mut app, 0.0), None, "the frame after Play draws the first step");
+        assert_eq!(frame(&mut app, 0.0), None);
+        assert!(app.ui.action_playing.is_none());
+        assert!(!app.ui.status.is_empty(), "the step's error shows");
+        assert_eq!(frame(&mut app, 0.0), None);
+        assert_eq!(x(&app), 1.0, "the step after the failing one does not run");
+    }
 }

crates/ui-egui/src/state.rs

@@ -496,6 +496,12 @@ pub struct UiState {
     /// adds a new action, as after Begin Recording.
     #[serde(skip)]
     pub recording_into: Option<u64>,
+    /// How actions play (Actions panel menu › Playback Options…), kept with the UI preferences.
+    #[serde(default, deserialize_with = "crate::panels::actions::deserialize_playback")]
+    pub action_playback: crate::panels::actions::PlaybackOptions,
+    /// The playback at Step by Step or Pause For in progress, if any. Not saved.
+    #[serde(skip)]
+    pub action_playing: Option<crate::panels::actions::Playing>,
     /// Keyboard shortcut overrides: command id, `tool:<id>` or `panel:<id>` → chord ("" = none),
     /// stored in the form every earlier version reads.
     #[serde(default, with = "crate::keymap::stored")]
@@ -970,6 +976,8 @@ impl Default for UiState {
             action_sets_selected: vec![],
             recording: None,
             recording_into: None,
+            action_playback: Default::default(),
+            action_playing: None,
             shortcut_overrides: Default::default(),
             shortcut_set: default_shortcut_set(),
             workspace: default_workspace(),

docs/mcp.md

@@ -1848,12 +1848,29 @@ already walks Image Trace. Short agent entry points:
   a text field has the keyboard, or while a tool is busy. Editing command shortcuts (`shortcuts.set`, Keyboard Shortcuts), loading preferences and
   `ui.actionSet.load` preserve action function keys. When several actions have the same key, the first in panel order
   plays. A stored key reserved on the current platform does not play an action.
-- Actions: `ui.action.play {action, set?}` plays the action named `action` as one undoable batch; `set` names the set
-  to look in (default: every set), and a `set` that is not a string is an error. A name that no action has, or that
-  more than one action in the sets looked in has, or whose every step is excluded, is an error, and then nothing plays.
+- Actions: `ui.action.play {action, set?}` plays the action named `action` at the speed `ui.action.playbackOptions`
+  sets; `set` names the set to look in (default: every set), and a `set` that is not a string is an error. At
+  Accelerated it plays the action as one undoable batch and returns what `command.batch` returns. At Step by Step and
+  Pause For it plays the first step at once and returns `{results: [the first step's result], pending}`, where
+  `pending` counts the steps still to play; the app plays them one at a time, each as its own undo step. When the next
+  step is due and the active document is not the one that was active after the step before (another document was
+  made active, or that document was closed), the playback ends with a status and the rest do not play; a step that
+  makes another document active itself does not end it. A name that no
+  action has, or that more than one action in the sets looked in has, or whose every step is excluded, is an error, and
+  then nothing plays. So is an action played while another is still playing at Step by Step or Pause For. A
+  `command.batch` step, which an action played or a panel operation run as one batch records, plays as its own steps,
+  here and in Batch….
+- Actions: `ui.action.playbackOptions {speed?, seconds?}` sets how the Actions panel plays actions and returns
+  `{speed, seconds}`. `speed` is `accelerated` (the default: every step at once), `step` (one step at a time, with the
+  window drawn after each step before the next runs) or `pause` (a pause of `seconds` between steps). `seconds` is a
+  whole number from 1 to 60, VectorCraft's own range, and stays set while another speed is chosen. A param left out
+  keeps its value. Any other `speed` or `seconds` is an error, and then nothing changes. The setting is kept with the UI
+  preferences. The panel menu's Playback Options… opens the `actionPlayback` dialog (`speed`, `seconds`), whose OK runs
+  this. Batch… (`action.batch`) plays every step at once whatever the setting.
 - Actions: `ui.action.stop {}` ends the recording in progress and keeps its steps, in the action `ui.action.new` made
-  for it, else in a new action after the last action of its set, and returns `{stopped}`. With nothing recording it
-  changes nothing. The panel's Stop Playing/Recording button runs this.
+  for it, else in a new action after the last action of its set, and returns `{stopped}`. It also ends an action
+  playing at Step by Step or Pause For: the steps already played stay, and the rest do not play. With nothing
+  recording or playing it changes nothing. The panel's Stop Playing/Recording button runs this.
 - Action sets: `ui.actionSet.delete {sets?: [index], ids?: [id]}` deletes the Actions panel's sets at these indexes
   (0 is the top set) with their actions, by default the current set, and returns `{deleted}`. An index past the last
   set is an error, and then no set is deleted. `ids` holds the panel's own set ids, which its question passes: the

docs/target-app-parity.md

@@ -581,6 +581,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   - Actions panel (record/playback, persisted), generic parameter dialogs for every "…" command.
   - Actions panel: the current set is kept with the UI preferences, so after a restart a recording goes into the set that was current, not into the first set. With no set current, Begin Recording records into the first set and makes it current.
   - Actions panel: expand an action to show its recorded steps, then clear a step's checkmark to keep it in the action but skip it during playback. The action and set checkmarks include or exclude all their steps; a mixed checkmark includes all. Alt/Option-clicking a step checkmark keeps that step as it was and applies the opposite inclusion state to the other steps in its action. This follows the public [Exclude commands from an action](https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/automate-actions/exclude-commands-from-actions.html) guide; the scope of the mixed-state and Alt-click behavior is VectorCraft's design. The exclusion survives UI restart, action duplication, and `.vcactions` save/load. Existing version 1 action set files load with every step included.
+  - Actions panel: the panel menu's Playback Options… sets how actions play: Accelerated (the default) plays every step at once, Step by Step plays one step at a time with the canvas drawn after each, and Pause For waits the given number of seconds between steps ([Specify playback speed](https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/automate-actions/specify-playback-speed.html); `ui.action.playbackOptions`). VectorCraft's own rules, which the page does not cover: the pause is a whole number of seconds from 1 to 60, the setting is kept with the UI preferences, a paced playback ends at Stop Playing/Recording or when a step comes due while another document is active, each step of a paced playback is its own undo step, and Batch… plays at full speed.
   - Actions panel: Delete Selection deletes the selected action set with its actions and keeps the other sets ([Actions panel overview](https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/automate-actions/actions-panel-overview.html); `ui.actionSet.delete`). VectorCraft's own rules, which the overview does not cover: deleting a set asks first, Shift-click on a set's name selects a range of sets to delete together, the panel menu's Delete does the same, and Default Actions and the last set can be deleted. Undo does not bring a deleted set back.
   - Actions panel: the panel menu's Duplicate copies the selected action, else the current action set with all its actions ([Actions panel overview](https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/automate-actions/actions-panel-overview.html); `ui.actionSet.duplicate`). VectorCraft's own rules, which the overview does not cover: the copy goes right after the original, is named after it with " copy" added and is selected.
   - Batch… over data sets names each file after the document and the data set (`action.batch`). It writes `/`, `\`, `:`, `<`, `>`, `"`, `|`, `?`, `*` and control characters in the data set's name as `-`, and adds `-2`, `-3`… to a name an earlier data set used.

docs/ui-parity.md

@@ -320,6 +320,7 @@ next unit in the order a right-click on a ruler lists them, from Feet back to Po
 | Toolbar without group labels by default, one or two columns; All Tools drawer by flyout group with shortcuts, its menu (Reset, Basic, Advanced) and Show section | done | #1751; a preference brings the labels back; `toolbar.show` sets the Fill/Stroke, Coloring, Draw Mode and Screen Mode controls |
 | Actions panel: ≡ › Save Actions… saves the current set with all its actions to a file and ≡ › Load Actions… adds a saved set ([Manage a set of actions](https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/automate-actions/manage-a-set-of-actions.html)) | partial | `ui.actionSet.save`, `ui.actionSet.load`; `panels/actions.rs` tests. The file is VectorCraft's own `.vcactions` JSON; the reference app's `.aia` files and Reset, Clear and Replace Actions remain |
 | Actions panel: ≡ › Action Options… renames the selected action and sets its function key and color ([Actions panel overview](https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/automate-actions/actions-panel-overview.html)) | partial | `ui.action.options`; `panels/actions.rs` tests (part of #1629). The color shows nowhere until Button Mode exists |
+| Actions panel: ≡ › Playback Options… plays actions Accelerated, Step by Step or with a pause between steps ([Specify playback speed](https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/automate-actions/specify-playback-speed.html)) | done | `ui.action.playbackOptions`; `panels/actions.rs` tests. The pause is a whole number of seconds from 1 to 60 (VectorCraft's own range); Batch… plays at full speed |
 | Actions panel: a clicked action stays selected for Play Current Selection and Delete Selection | partial | #1853 (part of #1629); editing actions and action shortcuts remain |
 | Actions panel: Create New Set (bottom bar, ≡ › New Set…) names a new set and Set Options… renames the current one; a click on a set's name makes it current and a recording goes into the current set ([helpx: Automation with actions](https://helpx.adobe.com/illustrator/using/automation-actions.html)); the current set is kept with the UI preferences, and with no set current a recording goes into the first set, which becomes current | partial | #3712; dragging actions between sets remains |
 | Actions panel: Create New Action (bottom bar, ≡ › New Action…) asks for the name, set, function key and color, and Record adds the action and records into it ([Create new actions](https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/automate-actions/record-actions.html)) | partial | `ui.action.new`, `ui.action.play`; `panels/actions.rs` tests. A function key plays its action, even when a command has the same shortcut, and the command keeps it. Button Mode, which shows the color, remains |