LRC-SS-PLAYBACK: slideshow playback: fades, random order, repeat, previews prepared in advance, playback controls

crates/engine/src/cmd/mod.rs

@@ -32,6 +32,7 @@ mod prefs;
 mod preset_files;
 pub mod previews;
 mod query;
+mod slideshow;
 mod sync;
 mod xmp;
 
@@ -144,6 +145,7 @@ pub fn command_specs() -> &'static [CommandSpec] {
         v.extend(xmp::specs());
         v.extend(preset_files::specs());
         v.extend(prefs::specs());
+        v.extend(slideshow::specs());
         v.extend(export::specs());
         v.extend(before::specs());
         v.extend(browse::specs());

crates/engine/src/cmd/slideshow.rs

@@ -0,0 +1,32 @@
+//! `slideshow.playback`: the slideshow's Playback settings (slide and fade durations, fade colour,
+//! random order, repeat, preparing previews in advance). A library preference, saved in the
+//! library's `prefs.json`; the app's slideshow (View ▸ Slideshow) plays with them.
+
+use serde_json::Value;
+
+use super::{CommandSpec, always, bad, cmd};
+use crate::{Result, Session};
+
+fn playback(s: &mut Session, p: &Value) -> Result<Value> {
+    let changes = p.as_object().is_some_and(|o| !o.is_empty());
+    if changes {
+        let next = s.slideshow.merged(p).map_err(|e| bad("slideshow.playback", e))?;
+        if next != s.slideshow {
+            s.slideshow = next;
+            s.save_prefs()?;
+        }
+    }
+    Ok(s.slideshow.to_json())
+}
+
+pub fn specs() -> Vec<CommandSpec> {
+    vec![cmd!(
+        "slideshow.playback",
+        "Slideshow Playback Settings",
+        [],
+        None,
+        "{slideDuration?: seconds (0.5–120), fadeDuration?: seconds (0 = cut; at most 10 and the slide duration), fadeColor?: \"#rrggbb\"|[r,g,b]|null (fade through a colour instead of crossfading), randomOrder?: bool, repeat?: bool, preparePreviews?: bool (render the next slides before they are due)} — omitted keys keep their value, {} reads them; saved with the library → {slideDuration, fadeDuration, fadeColor, randomOrder, repeat, preparePreviews}",
+        always,
+        playback
+    )]
+}