Add helper module egui::gui_zoom for zooming an app

crates/egui/src/data/input.rs

@@ -522,7 +522,7 @@ impl ModifierNames<'static> {
         alt: "Alt",
         ctrl: "Ctrl",
         shift: "Shift",
-        mac_cmd: "Command",
+        mac_cmd: "Cmd",
         concat: "+",
     };
 }

crates/egui/src/gui_zoom.rs

@@ -0,0 +1,102 @@
+//! Helpers for zooming the whole GUI (changing [`Context::pixels_per_point`].
+use crate::*;
+
+/// The suggested keyboard shortcuts for global gui zooming.
+pub mod kb_shortcuts {
+    use super::*;
+
+    // Using winit on Mac the key with the Plus sign on it is reported as the Equals key
+    // (with both English and Swedish keyboard).
+    pub const ZOOM_IN: KeyboardShortcut = KeyboardShortcut::new(Modifiers::COMMAND, Key::Equals);
+    pub const ZOOM_OUT: KeyboardShortcut = KeyboardShortcut::new(Modifiers::COMMAND, Key::Minus);
+    pub const ZOOM_RESET: KeyboardShortcut = KeyboardShortcut::new(Modifiers::COMMAND, Key::Num0);
+}
+
+/// Let the user scale the GUI (change `Context::pixels_per_point`) by pressing
+/// Cmd+Plus, Cmd+Minus or Cmd+0, just like in a browser.
+///
+/// When using [`eframe`](https://github.com/emilk/egui/tree/master/crates/eframe), you want to call this as:
+/// ```ignore
+/// // On web, the browser controls `pixels_per_point`.
+/// if !frame.is_web() {
+///     egui::gui_zoom::scale_ui_with_keyboard_shortcuts(
+///         ctx,
+///         frame.info().native_pixels_per_point,
+///     );
+/// }
+/// ```
+pub fn scale_ui_with_keyboard_shortcuts(ctx: &Context, native_pixels_per_point: Option<f32>) {
+    if ctx.input_mut().consume_shortcut(&kb_shortcuts::ZOOM_RESET) {
+        if let Some(native_pixels_per_point) = native_pixels_per_point {
+            ctx.set_pixels_per_point(native_pixels_per_point);
+        }
+    } else {
+        if ctx.input_mut().consume_shortcut(&kb_shortcuts::ZOOM_IN) {
+            zoom_in(ctx);
+        }
+        if ctx.input_mut().consume_shortcut(&kb_shortcuts::ZOOM_OUT) {
+            zoom_out(ctx);
+        }
+    }
+}
+
+const MIN_PIXELS_PER_POINT: f32 = 0.2;
+const MAX_PIXELS_PER_POINT: f32 = 4.0;
+
+/// Make everything larger.
+pub fn zoom_in(ctx: &Context) {
+    let mut pixels_per_point = ctx.pixels_per_point();
+    pixels_per_point += 0.1;
+    pixels_per_point = pixels_per_point.clamp(MIN_PIXELS_PER_POINT, MAX_PIXELS_PER_POINT);
+    pixels_per_point = (pixels_per_point * 10.).round() / 10.;
+    ctx.set_pixels_per_point(pixels_per_point);
+}
+
+/// Make everything smaller.
+pub fn zoom_out(ctx: &Context) {
+    let mut pixels_per_point = ctx.pixels_per_point();
+    pixels_per_point -= 0.1;
+    pixels_per_point = pixels_per_point.clamp(MIN_PIXELS_PER_POINT, MAX_PIXELS_PER_POINT);
+    pixels_per_point = (pixels_per_point * 10.).round() / 10.;
+    ctx.set_pixels_per_point(pixels_per_point);
+}
+
+/// Show buttons for zooming the ui.
+pub fn zoom_menu_buttons(ui: &mut Ui, native_pixels_per_point: Option<f32>) {
+    if ui
+        .add_enabled(
+            ui.ctx().pixels_per_point() < MAX_PIXELS_PER_POINT,
+            Button::new("Zoom In").shortcut_text(ui.ctx().format_shortcut(&kb_shortcuts::ZOOM_IN)),
+        )
+        .clicked()
+    {
+        zoom_in(ui.ctx());
+        ui.close_menu();
+    }
+
+    if ui
+        .add_enabled(
+            ui.ctx().pixels_per_point() > MIN_PIXELS_PER_POINT,
+            Button::new("Zoom Out")
+                .shortcut_text(ui.ctx().format_shortcut(&kb_shortcuts::ZOOM_OUT)),
+        )
+        .clicked()
+    {
+        zoom_out(ui.ctx());
+        ui.close_menu();
+    }
+
+    if let Some(native_pixels_per_point) = native_pixels_per_point {
+        if ui
+            .add_enabled(
+                ui.ctx().pixels_per_point() != native_pixels_per_point,
+                Button::new("Reset Zoom")
+                    .shortcut_text(ui.ctx().format_shortcut(&kb_shortcuts::ZOOM_RESET)),
+            )
+            .clicked()
+        {
+            ui.ctx().set_pixels_per_point(native_pixels_per_point);
+            ui.close_menu();
+        }
+    }
+}

crates/egui/src/lib.rs

@@ -305,6 +305,7 @@ mod context;
 mod data;
 mod frame_state;
 pub(crate) mod grid;
+pub mod gui_zoom;
 mod id;
 mod input_state;
 pub mod introspection;

crates/egui_demo_app/src/wrap_app.rs

@@ -212,7 +212,10 @@ impl eframe::App for WrapApp {
 
         // On web, the browser controls `pixels_per_point`.
         if !frame.is_web() {
-            scale_ui_with_keyboard_shortcuts(ctx, frame.info().native_pixels_per_point);
+            egui::gui_zoom::scale_ui_with_keyboard_shortcuts(
+                ctx,
+                frame.info().native_pixels_per_point,
+            );
         }
     }
 
@@ -404,38 +407,3 @@ fn clock_button(ui: &mut egui::Ui, seconds_since_midnight: f64) -> egui::Respons
 
     ui.button(egui::RichText::new(time).monospace())
 }
-
-/// Let the user scale the GUI (change `pixels_per_point`) by pressing
-/// Cmd+Plus, Cmd+Minus or Cmd+0, just like in a browser.
-fn scale_ui_with_keyboard_shortcuts(ctx: &egui::Context, native_pixels_per_point: Option<f32>) {
-    // Using winit on Mac the key with the Plus sign on it is reported as the Equals key
-    // (with both English and Swedish keyboard).
-    let zoom_in = egui::KeyboardShortcut::new(egui::Modifiers::COMMAND, egui::Key::Equals);
-    let zoom_out = egui::KeyboardShortcut::new(egui::Modifiers::COMMAND, egui::Key::Minus);
-    let reset = egui::KeyboardShortcut::new(egui::Modifiers::COMMAND, egui::Key::Num0);
-
-    let zoom_in = ctx.input_mut().consume_shortcut(&zoom_in);
-    let zoom_out = ctx.input_mut().consume_shortcut(&zoom_out);
-    let reset = ctx.input_mut().consume_shortcut(&reset);
-
-    let mut pixels_per_point = ctx.pixels_per_point();
-
-    if zoom_in {
-        pixels_per_point += 0.1;
-    }
-    if zoom_out {
-        pixels_per_point -= 0.1;
-    }
-    pixels_per_point = pixels_per_point.clamp(0.2, 5.);
-    pixels_per_point = (pixels_per_point * 10.).round() / 10.;
-    if reset {
-        if let Some(native_pixels_per_point) = native_pixels_per_point {
-            pixels_per_point = native_pixels_per_point;
-        }
-    }
-
-    if pixels_per_point != ctx.pixels_per_point() {
-        tracing::debug!("Changed GUI scale to {}", pixels_per_point);
-        ctx.set_pixels_per_point(pixels_per_point);
-    }
-}

crates/egui_demo_lib/src/demo/demo_app_windows.rs

@@ -321,6 +321,13 @@ fn file_menu_button(ui: &mut Ui) {
         ui.set_min_width(220.0);
         ui.style_mut().wrap = Some(false);
 
+        // On the web the browser controls the zoom
+        #[cfg(not(target_arch = "wasm32"))]
+        {
+            egui::gui_zoom::zoom_menu_buttons(ui, None);
+            ui.separator();
+        }
+
         if ui
             .add(
                 egui::Button::new("Organize Windows")