feat(options): interface scale for the whole window

On a non-Retina screen macOS draws the interface at 1x, which reads small
on a Full HD monitor, and there was no way to enlarge it. Options >
Display now offers an interface scale of 75–200 % in 25 % steps, applied
through the window's scale factor on top of the display's own and kept
with the user settings. It is a list rather than a slider because the
dialog rescales under the pointer as the value changes.

Fixes #1655

Co-Authored-By: Claude Opus 5.5 <[email protected]>

locales/ar-SA/opencadstudio.ftl

@@ -1451,6 +1451,7 @@ common =
     .zoom = التكبير
     .reverse-mouse-wheel-zoom-zoomwheel = عكس التكبير بعجلة الفأرة (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = لوحة اللمس: التمرير يحرك العرض، Ctrl+تمرير أو القرص يكبّر
+    .interface-scale = مقياس الواجهة
     .zoom-factor = معامل التكبير
     .how-far-one-wheel-notch-zooms-zoomfactor = مقدار التكبير لكل درجة من العجلة (ZOOMFACTOR).
     .text-and-dimensions = النص والأبعاد

locales/bg-BG/opencadstudio.ftl

@@ -1438,6 +1438,7 @@ common =
     .zoom = Мащабиране
     .reverse-mouse-wheel-zoom-zoomwheel = Обръщане на мащабирането с колелцето (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Тъчпад: превъртането мести изгледа, Ctrl+превъртане или щипване мащабира
+    .interface-scale = Мащаб на интерфейса
     .zoom-factor = Коефициент на мащабиране
     .how-far-one-wheel-notch-zooms-zoomfactor = Колко мащабира едно щракване на колелцето (ZOOMFACTOR).
     .text-and-dimensions = Текст и размери

locales/cs-CZ/opencadstudio.ftl

@@ -1438,6 +1438,7 @@ common =
     .zoom = Zoom
     .reverse-mouse-wheel-zoom-zoomwheel = Obrátit zoom kolečkem myši (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Touchpad: posun posouvá pohled, Ctrl+posun nebo sevření zvětšuje
+    .interface-scale = Měřítko rozhraní
     .zoom-factor = Faktor zoomu
     .how-far-one-wheel-notch-zooms-zoomfactor = O kolik přiblíží jeden zub kolečka (ZOOMFACTOR).
     .text-and-dimensions = Text a kóty

locales/de-DE/opencadstudio.ftl

@@ -1439,6 +1439,7 @@ common =
     .zoom = Zoom
     .reverse-mouse-wheel-zoom-zoomwheel = Mausradzoom umkehren (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Touchpad: Scrollen verschiebt, Strg+Scrollen oder Zusammenziehen zoomt
+    .interface-scale = Oberflächenskalierung
     .zoom-factor = Zoomfaktor
     .how-far-one-wheel-notch-zooms-zoomfactor = Wie weit eine Radrastung zoomt (ZOOMFACTOR).
     .text-and-dimensions = Text und Bemaßung

locales/el-GR/opencadstudio.ftl

@@ -1440,6 +1440,7 @@ common =
     .zoom = Ζουμ
     .reverse-mouse-wheel-zoom-zoomwheel = Αντιστροφή ζουμ με τον τροχό (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Επιφάνεια αφής: η κύλιση μετακινεί, Ctrl+κύλιση ή τσίμπημα κάνει ζουμ
+    .interface-scale = Κλίμακα διεπαφής
     .zoom-factor = Συντελεστής ζουμ
     .how-far-one-wheel-notch-zooms-zoomfactor = Πόσο ζουμάρει ένα σκαλί του τροχού (ZOOMFACTOR).
     .text-and-dimensions = Κείμενο και διαστάσεις

locales/en-US/opencadstudio.ftl

@@ -1440,6 +1440,7 @@ common =
     .zoom = Zoom
     .reverse-mouse-wheel-zoom-zoomwheel = Reverse mouse wheel zoom (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Touchpad: scroll pans, Ctrl+scroll or pinch zooms
+    .interface-scale = Interface scale
     .zoom-factor = Zoom factor
     .how-far-one-wheel-notch-zooms-zoomfactor = How far one wheel notch zooms (ZOOMFACTOR).
     .text-and-dimensions = Text and Dimensions

locales/es-ES/opencadstudio.ftl

@@ -1439,6 +1439,7 @@ common =
     .zoom = Zoom
     .reverse-mouse-wheel-zoom-zoomwheel = Invertir el zoom de la rueda del ratón (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Panel táctil: el desplazamiento encuadra, Ctrl+desplazamiento o pellizco hace zoom
+    .interface-scale = Escala de la interfaz
     .zoom-factor = Factor de zoom
     .how-far-one-wheel-notch-zooms-zoomfactor = Cuánto amplía un paso de la rueda (ZOOMFACTOR).
     .text-and-dimensions = Texto y acotación

locales/fi-FI/opencadstudio.ftl

@@ -1438,6 +1438,7 @@ common =
     .zoom = Zoomaus
     .reverse-mouse-wheel-zoom-zoomwheel = Käännä hiiren rullan zoomaus (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Kosketuslevy: vieritys panoroi, Ctrl+vieritys tai nipistys zoomaa
+    .interface-scale = Käyttöliittymän skaalaus
     .zoom-factor = Zoomauskerroin
     .how-far-one-wheel-notch-zooms-zoomfactor = Kuinka paljon yksi rullan pykälä zoomaa (ZOOMFACTOR).
     .text-and-dimensions = Teksti ja mitoitus

locales/fr-FR/opencadstudio.ftl

@@ -1439,6 +1439,7 @@ common =
     .zoom = Zoom
     .reverse-mouse-wheel-zoom-zoomwheel = Inverser le zoom à la molette (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Pavé tactile : le défilement déplace, Ctrl+défilement ou pincement zoome
+    .interface-scale = Échelle de l'interface
     .zoom-factor = Facteur de zoom
     .how-far-one-wheel-notch-zooms-zoomfactor = De combien zoome un cran de molette (ZOOMFACTOR).
     .text-and-dimensions = Texte et cotation

locales/hi-IN/opencadstudio.ftl

@@ -1427,6 +1427,7 @@ common =
     .zoom = ज़ूम
     .reverse-mouse-wheel-zoom-zoomwheel = माउस व्हील ज़ूम उलटें (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = टचपैड: स्क्रॉल पैन करता है, Ctrl+स्क्रॉल या पिंच ज़ूम करता है
+    .interface-scale = इंटरफ़ेस स्केल
     .zoom-factor = ज़ूम गुणक
     .how-far-one-wheel-notch-zooms-zoomfactor = व्हील का एक पायदान कितना ज़ूम करता है (ZOOMFACTOR)।
     .text-and-dimensions = पाठ और आयाम

locales/hu-HU/opencadstudio.ftl

@@ -1438,6 +1438,7 @@ common =
     .zoom = Nagyítás
     .reverse-mouse-wheel-zoom-zoomwheel = Egérgörgős nagyítás megfordítása (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Érintőpad: a görgetés mozgat, a Ctrl+görgetés vagy csippentés nagyít
+    .interface-scale = Felület mérete
     .zoom-factor = Nagyítási tényező
     .how-far-one-wheel-notch-zooms-zoomfactor = Mennyit nagyít egy görgőkattanás (ZOOMFACTOR).
     .text-and-dimensions = Szöveg és méretezés

locales/it-IT/opencadstudio.ftl

@@ -1438,6 +1438,7 @@ common =
     .zoom = Zoom
     .reverse-mouse-wheel-zoom-zoomwheel = Inverti lo zoom con la rotellina (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Touchpad: lo scorrimento sposta la vista, Ctrl+scorrimento o pizzico esegue lo zoom
+    .interface-scale = Scala dell'interfaccia
     .zoom-factor = Fattore di zoom
     .how-far-one-wheel-notch-zooms-zoomfactor = Di quanto ingrandisce uno scatto della rotellina (ZOOMFACTOR).
     .text-and-dimensions = Testo e quote

locales/ja-JP/opencadstudio.ftl

@@ -1429,6 +1429,7 @@ common =
     .zoom = ズーム
     .reverse-mouse-wheel-zoom-zoomwheel = マウス ホイールのズーム方向を反転 (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = タッチパッド: スクロールで画面移動、Ctrl+スクロールまたはピンチでズーム
+    .interface-scale = インターフェースの拡大率
     .zoom-factor = ズーム倍率
     .how-far-one-wheel-notch-zooms-zoomfactor = ホイール 1 ノッチのズーム量 (ZOOMFACTOR)。
     .text-and-dimensions = 文字と寸法

locales/ko-KR/opencadstudio.ftl

@@ -1438,6 +1438,7 @@ common =
     .zoom = 줌
     .reverse-mouse-wheel-zoom-zoomwheel = 마우스 휠 줌 방향 반전 (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = 터치패드: 스크롤은 화면 이동, Ctrl+스크롤 또는 핀치는 확대/축소
+    .interface-scale = 인터페이스 배율
     .zoom-factor = 줌 배율
     .how-far-one-wheel-notch-zooms-zoomfactor = 휠 한 칸이 확대하는 정도 (ZOOMFACTOR).
     .text-and-dimensions = 문자 및 치수

locales/lo-LA/opencadstudio.ftl

@@ -1440,6 +1440,7 @@ common =
     .zoom = ຊູມ
     .reverse-mouse-wheel-zoom-zoomwheel = ສະຫຼັບທິດທາງການໝຸນລໍ້ເມົາສ໌ຊູມ (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = ທັດແພດ: ເລື່ອນເພື່ອຍ້າຍມຸມມອງ, Ctrl+ເລື່ອນ ຫຼື ບີບເພື່ອຊູມ
+    .interface-scale = ຂະໜາດສ່ວນຕິດຕໍ່
     .zoom-factor = ຕົວຄູນການຊູມ
     .how-far-one-wheel-notch-zooms-zoomfactor = ໄລຍະຊູມຕໍ່ການໝຸນລໍ້ເມົາສ໌ໜຶ່ງຄລິກ (ZOOMFACTOR).
     .text-and-dimensions = ຂໍ້ຄວາມ ແລະ ຂະໜາດ

locales/nl-NL/opencadstudio.ftl

@@ -1437,6 +1437,7 @@ common =
     .zoom = Zoomen
     .reverse-mouse-wheel-zoom-zoomwheel = Muiswielzoom omkeren (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Touchpad: scrollen verschuift, Ctrl+scrollen of knijpen zoomt
+    .interface-scale = Interfaceschaal
     .zoom-factor = Zoomfactor
     .how-far-one-wheel-notch-zooms-zoomfactor = Hoeveel één wielklik zoomt (ZOOMFACTOR).
     .text-and-dimensions = Tekst en maatvoering

locales/pl-PL/opencadstudio.ftl

@@ -1438,6 +1438,7 @@ common =
     .zoom = Powiększenie
     .reverse-mouse-wheel-zoom-zoomwheel = Odwróć powiększanie kółkiem myszy (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Touchpad: przewijanie przesuwa widok, Ctrl+przewijanie lub szczypanie powiększa
+    .interface-scale = Skala interfejsu
     .zoom-factor = Współczynnik powiększenia
     .how-far-one-wheel-notch-zooms-zoomfactor = O ile powiększa jedno kliknięcie kółka (ZOOMFACTOR).
     .text-and-dimensions = Tekst i wymiary

locales/pt-BR/opencadstudio.ftl

@@ -1439,6 +1439,7 @@ common =
     .zoom = Zoom
     .reverse-mouse-wheel-zoom-zoomwheel = Inverter o zoom da roda do mouse (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Touchpad: rolar move a vista, Ctrl+rolar ou pinçar aplica zoom
+    .interface-scale = Escala da interface
     .zoom-factor = Fator de zoom
     .how-far-one-wheel-notch-zooms-zoomfactor = Quanto um passo da roda amplia (ZOOMFACTOR).
     .text-and-dimensions = Texto e cotas

locales/ru-RU/opencadstudio.ftl

@@ -1442,6 +1442,7 @@ common =
     .zoom = Зумирование
     .reverse-mouse-wheel-zoom-zoomwheel = Обратить зумирование колесом мыши (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Тачпад: прокрутка панорамирует, Ctrl+прокрутка или щипок масштабирует
+    .interface-scale = Масштаб интерфейса
     .zoom-factor = Коэффициент зумирования
     .how-far-one-wheel-notch-zooms-zoomfactor = Насколько приближает один щелчок колеса (ZOOMFACTOR).
     .text-and-dimensions = Текст и размеры

locales/tr-TR/opencadstudio.ftl

@@ -1425,6 +1425,7 @@ common =
     .zoom = Yakınlaştırma
     .reverse-mouse-wheel-zoom-zoomwheel = Fare tekerleği yakınlaştırmasını ters çevir (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = Dokunmatik yüzey: kaydırma kaydırır, Ctrl+kaydırma veya sıkıştırma yakınlaştırır
+    .interface-scale = Arayüz ölçeği
     .zoom-factor = Yakınlaştırma çarpanı
     .how-far-one-wheel-notch-zooms-zoomfactor = Bir tekerlek adımının ne kadar yakınlaştıracağı (ZOOMFACTOR).
     .text-and-dimensions = Metin ve ölçülendirme

locales/zh-CN/opencadstudio.ftl

@@ -1426,6 +1426,7 @@ common =
     .zoom = 缩放
     .reverse-mouse-wheel-zoom-zoomwheel = 反转鼠标滚轮缩放方向 (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = 触控板：滚动平移，Ctrl+滚动或捏合缩放
+    .interface-scale = 界面缩放
     .zoom-factor = 缩放系数
     .how-far-one-wheel-notch-zooms-zoomfactor = 滚轮每格的缩放幅度 (ZOOMFACTOR)。
     .text-and-dimensions = 文字和标注

locales/zh-TW/opencadstudio.ftl

@@ -1438,6 +1438,7 @@ common =
     .zoom = 縮放
     .reverse-mouse-wheel-zoom-zoomwheel = 反轉滑鼠滾輪縮放方向 (ZOOMWHEEL)
     .touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms = 觸控板：捲動平移，Ctrl+捲動或捏合縮放
+    .interface-scale = 介面縮放
     .zoom-factor = 縮放係數
     .how-far-one-wheel-notch-zooms-zoomfactor = 滾輪每一格的縮放幅度 (ZOOMFACTOR)。
     .text-and-dimensions = 文字與標註

src/app/mod.rs

@@ -561,6 +561,8 @@ pub(super) struct OpenCADStudio {
     zoom_wheel_reversed: bool,
     /// Scroll pans and Ctrl+scroll zooms (touchpads); see `scroll_intent`.
     touchpad_pan: bool,
+    /// Interface scale in percent, applied through the window scale factor.
+    ui_scale_percent: u16,
     /// Mouse-wheel zoom sensitivity (ZOOMFACTOR), held inside
     /// `settings::ZOOM_FACTOR_MIN..=settings::ZOOM_FACTOR_MAX`. `SETVAR`
     /// only sets the range the system variable itself has; the Options
@@ -2378,6 +2380,8 @@ pub enum Message {
     /// Toggle reversing the mouse-wheel zoom direction (ZOOMWHEEL).
     ZoomWheelReversedChanged(bool),
     TouchpadPanChanged(bool),
+    /// Interface scale in percent (Options > Display).
+    UiScaleChanged(u16),
     /// Change how far one wheel notch zooms, from the Options slider
     /// (ZOOMFACTOR).
     ZoomFactorChanged(i32),
@@ -4161,6 +4165,7 @@ impl OpenCADStudio {
             polar_increment_deg: 45.0,
             zoom_wheel_reversed: false,
             touchpad_pan: false,
+            ui_scale_percent: 100,
             zoom_factor: 60,
             zoom_factor_input: 60.to_string(),
             cursor_size: 5,
@@ -4904,6 +4909,7 @@ pub fn run() -> iced::Result {
         ..iced::Settings::default()
     })
     .subscription(OpenCADStudio::subscription)
+    .scale_factor(|state: &OpenCADStudio, _| f32::from(state.ui_scale_percent) / 100.0)
     .title(|state: &OpenCADStudio, window_id: window::Id| {
         let _ = window_id; // all dialogs are in-canvas modals now
         if let Some(tab) = state.tabs.get(state.active_tab) {

src/app/settings.rs

@@ -183,6 +183,11 @@ pub const ZOOM_FACTOR_MAX: i32 = 500;
 /// Hold a ZOOMFACTOR inside the range the application can store, wherever it
 /// arrives from — the slider, the Options field, or a configuration file
 /// written by hand or by an older build.
+/// Interface scale in percent, kept to the range the Options slider offers.
+pub fn clamp_ui_scale(percent: u16) -> u16 {
+    percent.clamp(75, 200)
+}
+
 pub fn clamp_zoom_factor(v: i32) -> i32 {
     v.clamp(ZOOM_FACTOR_MIN, ZOOM_FACTOR_MAX)
 }
@@ -391,6 +396,8 @@ pub struct UserSettings {
     /// Scrolling pans and Ctrl+scroll (a touchpad pinch) zooms, for a
     /// touchpad that reports two-finger drags as wheel scrolls.
     pub touchpad_pan: bool,
+    /// Interface scale in percent, on top of the display's own scale.
+    pub ui_scale_percent: u16,
     pub zoom_factor: i32,
     /// CURSORSIZE: normalized crosshair reach; 5 retains the original 60 px arms.
     pub cursor_size: i32,
@@ -811,6 +818,7 @@ impl Default for UserSettings {
             polar_increment_deg: 45.0,
             zoom_wheel_reversed: false,
             touchpad_pan: false,
+            ui_scale_percent: 100,
             zoom_factor: 60,
             cursor_size: 5,
             pick_box: 3,

src/app/update/file.rs

@@ -663,6 +663,7 @@ impl OpenCADStudio {
             polar_increment_deg: self.polar_increment_deg,
             zoom_wheel_reversed: self.zoom_wheel_reversed,
             touchpad_pan: self.touchpad_pan,
+            ui_scale_percent: self.ui_scale_percent,
             zoom_factor: self.zoom_factor,
             cursor_size: self.cursor_size,
             pick_box: self.pick_box,
@@ -764,6 +765,7 @@ impl OpenCADStudio {
         self.polar_increment_deg = s.polar_increment_deg;
         self.zoom_wheel_reversed = s.zoom_wheel_reversed;
         self.touchpad_pan = s.touchpad_pan;
+        self.ui_scale_percent = crate::app::settings::clamp_ui_scale(s.ui_scale_percent);
         self.zoom_factor = crate::app::settings::clamp_zoom_factor(s.zoom_factor);
         // Like the drafting-rotation field below, the Options field edits a
         // buffer rather than the value, so it is reseeded whenever the value

src/app/update/mod.rs

@@ -8391,6 +8391,12 @@ impl OpenCADStudio {
                 Task::none()
             }
 
+            Message::UiScaleChanged(percent) => {
+                self.ui_scale_percent = crate::app::settings::clamp_ui_scale(percent);
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
             Message::ZoomFactorChanged(factor) => {
                 self.zoom_factor = crate::app::settings::clamp_zoom_factor(factor);
                 // The field beside the slider reads the same value, so the

src/app/view/modal.rs

@@ -317,6 +317,7 @@ impl OpenCADStudio {
                             commandline_fade_ms: self.commandline_fade_ms,
                             zoom_wheel_reversed: self.zoom_wheel_reversed,
                             touchpad_pan: self.touchpad_pan,
+                            ui_scale_percent: self.ui_scale_percent,
                             zoom_factor: self.zoom_factor,
                             texteditmode: self.texteditmode,
                             dimension_continue_mode: self.dimension_continue_mode,

src/locale_catalog.rs

@@ -4798,6 +4798,7 @@ pub(super) fn message_attribute(source: &str) -> Option<(&'static str, &'static
         "Zoom" => Some(("common", "zoom")),
         "Reverse mouse wheel zoom (ZOOMWHEEL)" => Some(("common", "reverse-mouse-wheel-zoom-zoomwheel")),
         "Touchpad: scroll pans, Ctrl+scroll or pinch zooms" => Some(("common", "touchpad-scroll-pans-ctrl-scroll-or-pinch-zooms")),
+        "Interface scale" => Some(("common", "interface-scale")),
         "Zoom factor" => Some(("common", "zoom-factor")),
         "How far one wheel notch zooms (ZOOMFACTOR)." => Some(("common", "how-far-one-wheel-notch-zooms-zoomfactor")),
         "Text and Dimensions" => Some(("common", "text-and-dimensions")),

src/ui/window/options.rs

@@ -61,6 +61,8 @@ pub struct AppPrefs {
     pub zoom_wheel_reversed: bool,
     /// Scroll pans and Ctrl+scroll zooms (touchpads).
     pub touchpad_pan: bool,
+    /// Interface scale in percent.
+    pub ui_scale_percent: u16,
     /// ZOOMFACTOR. The slider sets the range the system variable has; the
     /// field beside it reaches `settings::ZOOM_FACTOR_MAX`.
     pub zoom_factor: i32,
@@ -679,6 +681,23 @@ pub fn view_window<'a>(
         .width(sizing.width),
         Space::new().height(12),
         color_controls,
+        Space::new().height(16),
+        // A list, not a slider: the dialog rescales under the cursor as the
+        // value changes, which would drag a slider along with it.
+        row![
+            text(crate::t!("Interface scale")).size(12).width(150),
+            iced::widget::pick_list(
+                Some(format!("{}%", prefs.ui_scale_percent)),
+                [75u16, 100, 125, 150, 175, 200].map(|p| format!("{p}%")).to_vec(),
+                |label: &String| label.clone(),
+            )
+            .on_select(|label: String| {
+                Message::UiScaleChanged(label.trim_end_matches('%').parse().unwrap_or(100))
+            })
+            .width(sizing.width),
+        ]
+        .spacing(12)
+        .align_y(iced::Center),
         Space::new().height(24),
         row![
             text(crate::t!("Model Space Appearance")).size(15),