Merge pull request #672 from vangel76/fix-457-ui-scale

#457: Settings > Appearance > UI Scale

crates/engine/src/settings.rs

@@ -104,6 +104,9 @@ pub struct AppearancePrefs {
     pub accessible_contrast: bool,
     /// Highlight (accent) colour of selections, focus and primary buttons (`#rrggbb`).
     pub highlight_color: String,
+    /// "UI Scale": `auto` (default: the scale the operating system reports) or a fixed
+    /// percentage of [`UI_SCALES`] (`100` = one point per physical pixel).
+    pub ui_scale: String,
 }
 
 impl Default for AppearancePrefs {
@@ -115,11 +118,19 @@ impl Default for AppearancePrefs {
             light_theme: "light".into(),
             accessible_contrast: false,
             highlight_color: DEFAULT_HIGHLIGHT.into(),
+            ui_scale: "auto".into(),
         }
     }
 }
 
 impl AppearancePrefs {
+    /// The fixed UI scale (physical pixels per point) "UI Scale" asks for, or `None` for `auto`
+    /// (and for a value outside [`UI_SCALES`]), which keeps the operating system's scale.
+    pub fn ui_scale_factor(&self) -> Option<f32> {
+        // `auto` doesn't parse; every other listed value is a positive whole percentage
+        UI_SCALES.iter().any(|(k, _)| *k == self.ui_scale).then(|| self.ui_scale.parse::<f32>().ok()).flatten().map(|pct| pct / 100.0)
+    }
+
     /// The theme to show (`darkest` | `dark` | `light`): the light or dark theme of the mode. Auto
     /// follows `system_light` (the operating system's appearance) and is dark without an answer.
     pub fn shown_theme(&self, system_light: Option<bool>) -> &str {
@@ -669,6 +680,17 @@ const BIN_OPEN: &[(&str, &str)] = &[("openInPlace", "Open in place"), ("openNewT
 const PROJECT_OPEN: &[(&str, &str)] = &[("openNewTab", "Open new tab"), ("openNewWindow", "Open in new window")];
 const THEMES: &[(&str, &str)] = &[("darkest", "Darkest"), ("dark", "Dark"), ("light", "Light")];
 pub const APPEARANCE_MODES: &[(&str, &str)] = &[("auto", "Sync with system"), ("dark", "Dark"), ("light", "Light")];
+pub const UI_SCALES: &[(&str, &str)] = &[
+    ("auto", "Auto (system)"),
+    ("75", "75%"),
+    ("100", "100%"),
+    ("125", "125%"),
+    ("150", "150%"),
+    ("175", "175%"),
+    ("200", "200%"),
+    ("250", "250%"),
+    ("300", "300%"),
+];
 pub const DARK_THEMES: &[(&str, &str)] = &[("darkest", "Darkest"), ("dark", "Dark")];
 pub const LIGHT_THEMES: &[(&str, &str)] = &[("light", "Light")];
 const MIXDOWN: &[(&str, &str)] = &[("front", "Front Only"), ("frontRear", "Front + Rear"), ("frontLfe", "Front + LFE"), ("frontRearLfe", "Front + Rear + LFE")];
@@ -795,6 +817,7 @@ static CATEGORIES: &[Category] = &[
             f("appearance.colorTheme", "Color Theme", Kind::Choice(THEMES), true),
             b("appearance.accessibleContrast", "Accessible color contrast", true),
             f("appearance.highlightColor", "Highlight Color", Kind::Color, true),
+            f("appearance.uiScale", "UI Scale", Kind::Choice(UI_SCALES), true),
         ],
     },
     Category {

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

@@ -3504,6 +3504,8 @@
 	Light Theme	Tema claro
 	Next Appearance Mode	Siguiente modo de apariencia
 	Sync with system	Sincronizar con el sistema
+	UI Scale	Escala de la interfaz
+	Auto (system)	Automática (sistema)
 	In	Entrada
 	Out	Salida
 	Export Markers as CSV…	Exportar marcadores como CSV…

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

@@ -3448,6 +3448,8 @@
 	Light Theme	ライトテーマ
 	Next Appearance Mode	次の外観モード
 	Sync with system	システムと同期
+	UI Scale	UI のスケール
+	Auto (system)	自動 (システム)
 	Go to previous keyframe	前のキーフレームへ移動
 	Go to next keyframe	次のキーフレームへ移動
 	Add keyframe	キーフレームを追加

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

@@ -3490,6 +3490,8 @@
 	Appearance Mode	外观模式
 	Next Appearance Mode	下一个外观模式
 	Sync with system	跟随系统
+	UI Scale	界面缩放
+	Auto (system)	自动（系统）
 	GPU Rendering	GPU 渲染
 	Composite on the GPU when available	可用时在 GPU 上合成
 	Text to Speech	文字转语音

crates/ui-egui/src/lib.rs

@@ -321,6 +321,8 @@ pub struct FilmcraftApp {
     watched_render: Option<(u64, Tick)>,
     /// Settings last applied to the UI (theme, tooltips, frame cache, audio device).
     applied_prefs: Option<filmcraft_engine::autosave::Preferences>,
+    /// Settings ▸ Appearance ▸ UI Scale last applied, with the system scale it was applied for.
+    applied_ui_scale: Option<(Option<f32>, f32)>,
     workspace_restored: bool,
     /// Window ▸ Workspaces: saved layouts ([`dock::WORKSPACES_FILE`] in the data directory).
     pub workspaces: dock::WorkspacePrefs,
@@ -528,6 +530,7 @@ impl FilmcraftApp {
             gpu: None,
             watched_render: None,
             applied_prefs: None,
+            applied_ui_scale: None,
             workspace_restored: false,
             workspaces,
             menu_workspaces: Default::default(),
@@ -587,9 +590,28 @@ impl FilmcraftApp {
         ctx.global_style_mut(|s| s.interaction.tooltip_delay = delay);
     }
 
+    /// Settings ▸ Appearance ▸ UI Scale: a fixed scale makes a point that many physical pixels,
+    /// whatever scale the system reports. It is applied only when the setting or the system scale
+    /// changes, so Ctrl+- / Ctrl++ still zoom the interface for the session; going back to Auto
+    /// restores the system's scale.
+    fn apply_ui_scale(&mut self, ctx: &egui::Context) {
+        let want = self.session.prefs.appearance.ui_scale_factor();
+        let native = ctx.native_pixels_per_point().filter(|v| v.is_finite() && *v > 0.0).unwrap_or(1.0);
+        if self.applied_ui_scale == Some((want, native)) {
+            return;
+        }
+        let prev = self.applied_ui_scale.replace((want, native));
+        match want {
+            Some(scale) => ctx.set_zoom_factor(scale / native),
+            None if prev.is_some_and(|(p, _)| p.is_some()) => ctx.set_zoom_factor(1.0),
+            None => {}
+        }
+    }
+
     /// Make the UI follow the settings after they change (theme, tooltips, frame cache budget,
     /// play after rendering, audio device).
     pub fn apply_prefs(&mut self, ctx: &egui::Context) {
+        self.apply_ui_scale(ctx);
         // Appearance Mode ▸ Sync with system: follow the system while running. The host reports
         // changes as they happen (no polling) and wakes the UI only when the value changes.
         if self.applied_prefs.is_some() {

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

@@ -785,6 +785,30 @@ mod tests {
     use super::*;
     use crate::theme::ThemeKind;
 
+    /// #457: on a desktop that reports 150%, UI Scale 100% makes a point one physical pixel. It is
+    /// applied once, so Ctrl+- still zooms for the session, and Auto gives the system's scale back.
+    #[test]
+    fn ui_scale_overrides_the_system_scale_and_auto_restores_it() {
+        let ctx = egui::Context::default();
+        let mut app = FilmcraftApp::new(filmcraft_engine::Session::default());
+        // a frame applying the settings, then the next one, where a new zoom takes effect
+        let pass = |app: &mut FilmcraftApp| {
+            let mut input = egui::RawInput::default();
+            input.viewports.entry(egui::ViewportId::ROOT).or_default().native_pixels_per_point = Some(1.5);
+            ctx.run_ui(input.clone(), |ui| app.apply_prefs(ui.ctx())).textures_delta.clear();
+            ctx.run_ui(input, |_| {}).textures_delta.clear();
+            ctx.zoom_factor()
+        };
+        assert_eq!(pass(&mut app), 1.0, "Auto keeps the system's scale");
+        app.session.execute("prefs.set", json!({"key": "appearance.uiScale", "value": "100"})).unwrap();
+        assert_eq!(pass(&mut app), 1.0 / 1.5, "100% is one physical pixel per point");
+        ctx.set_zoom_factor(0.9 / 1.5); // Ctrl+-
+        assert_eq!(pass(&mut app), 0.9 / 1.5, "a session zoom isn't undone every frame");
+        assert!(app.session.execute("prefs.set", json!({"key": "appearance.uiScale", "value": "130"})).is_err());
+        app.session.execute("prefs.set", json!({"key": "appearance.uiScale", "value": "auto"})).unwrap();
+        assert_eq!(pass(&mut app), 1.0);
+    }
+
     #[test]
     fn appearance_button_cycles_modes_without_losing_theme_choices() {
         let ctx = egui::Context::default();