Launcher: the accent a drag leaves off the strip, and the CLI's hue

Review fixes on top of the hue strip:

- A drag released outside the strip now writes settings.json too. on_mouse_up
  only fires while the element is hovered, so the accent stayed in memory and
  was lost on restart; on_mouse_up_out covers the release off it, and
  hue_dragging keeps a click elsewhere on the page from saving.
- The contrast test sweeps every half degree from 0 to 359.5 on both bases
  instead of two hand-picked hues, so the guarantee is tested where it is
  claimed.
- `settings accent <value>` names the degrees a value may be, not only the
  seven names.

Co-Authored-By: Hermes Agent (Nous Research) <[email protected]>

launcher/src/cli.rs

@@ -994,7 +994,10 @@ fn set_setting(s: &mut backend::Settings, key: &str, value: &str) -> Result<(),
             use horizon_launcher::themes::Accent;
             s.accent = Accent::parse(value).ok_or_else(|| {
                 let names: Vec<_> = Accent::ALL.iter().map(|a| a.name()).collect();
-                format!("{value}: say {}", names.join(", "))
+                format!(
+                    "{value}: say {} or a hue in degrees (0 to 360)",
+                    names.join(", ")
+                )
             })?
         }
         "background" => {

launcher/src/main.rs

@@ -218,6 +218,8 @@ struct Launcher {
     /// Where the accent picker's hue strip is on screen (`themes_page.rs`), to map a click to a
     /// hue.
     hue_area: std::rc::Rc<std::cell::Cell<Option<Bounds<gpui::Pixels>>>>,
+    /// A drag on that strip is in flight, so a release anywhere writes the accent down.
+    hue_dragging: bool,
     /// Settings > Language's dropdown (`language_page.rs`).
     language_menu: bool,
     /// The top bar's quick switch of who plays (`switch_page.rs`).
@@ -468,6 +470,7 @@ impl Launcher {
             confirm_remove: None,
             picker_open: false,
             hue_area: std::rc::Rc::new(std::cell::Cell::new(None)),
+            hue_dragging: false,
             language_menu: false,
             account_menu: false,
             menu_closed_at: None,

launcher/src/themes/tests.rs

@@ -14,7 +14,7 @@ fn every_accent_reads_as_well_as_the_violet() {
     for base in [NIGHT.blocks(), DAWN.blocks()] {
         for accent in Accent::ALL
             .into_iter()
-            .chain([Accent::custom(96.), Accent::custom(300.)])
+            .chain((0..720).map(|i| Accent::custom(i as f32 * 0.5)))
         {
             let p = accent.apply(base);
             let what = format!(

launcher/src/themes_page.rs

@@ -154,10 +154,22 @@ impl Launcher {
             }))
             .on_mouse_up(
                 MouseButton::Left,
-                cx.listener(|this, _: &MouseUpEvent, _, _| {
-                    this.settings.save();
-                }),
+                cx.listener(|this, _: &MouseUpEvent, _, _| this.finish_hue()),
             )
+            // `on_mouse_up` fires only while the strip is hovered, so a drag released off it would
+            // keep its accent in memory and never write it.
+            .on_mouse_up_out(
+                MouseButton::Left,
+                cx.listener(|this, _: &MouseUpEvent, _, _| this.finish_hue()),
+            )
+    }
+
+    /// A release ends the drag and writes `settings.json` once.
+    fn finish_hue(&mut self) {
+        if self.hue_dragging {
+            self.hue_dragging = false;
+            self.settings.save();
+        }
     }
 
     /// The hue under the pointer, as the accent. Saving waits until the mouse comes up, so a drag
@@ -172,6 +184,7 @@ impl Launcher {
         }
         let across: f32 = (at.x - area.origin.x).into();
         self.settings.accent = Accent::custom((across / width).clamp(0., 1.) * 360.);
+        self.hue_dragging = true;
         self.theme = self.settings_theme(window);
         cx.notify();
     }