eframe: add set_minimized and set_maximized (#2292)

* add actions for window controls

* add maximized to WindowInfo
update button text
fix clippy

* add overlap icon when maximized

* remove argument `app`

* remove WindowInfo { maximized }

* Update minimum window size

* Double-click titlebar to toggle maximized state

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

crates/eframe/src/epi.rs

@@ -718,6 +718,18 @@ impl Frame {
         self.output.close = true;
     }
 
+    /// Minimize or unminimize window. (native only)
+    #[cfg(not(target_arch = "wasm32"))]
+    pub fn set_minimized(&mut self, minimized: bool) {
+        self.output.minimized = Some(minimized);
+    }
+
+    /// Maximize or unmaximize window. (native only)
+    #[cfg(not(target_arch = "wasm32"))]
+    pub fn set_maximized(&mut self, maximized: bool) {
+        self.output.maximized = Some(maximized);
+    }
+
     /// Tell `eframe` to close the desktop window.
     #[cfg(not(target_arch = "wasm32"))]
     #[deprecated = "Renamed `close`"]
@@ -1011,5 +1023,13 @@ pub(crate) mod backend {
         /// Set to some bool to tell the window always on top.
         #[cfg(not(target_arch = "wasm32"))]
         pub always_on_top: Option<bool>,
+
+        /// Set to some bool to minimize or unminimize window.
+        #[cfg(not(target_arch = "wasm32"))]
+        pub minimized: Option<bool>,
+
+        /// Set to some bool to maximize or unmaximize window.
+        #[cfg(not(target_arch = "wasm32"))]
+        pub maximized: Option<bool>,
     }
 }

crates/eframe/src/native/epi_integration.rs

@@ -207,6 +207,8 @@ pub fn handle_app_output(
         window_pos,
         visible: _, // handled in post_present
         always_on_top,
+        minimized,
+        maximized,
     } = app_output;
 
     if let Some(decorated) = decorated {
@@ -250,6 +252,14 @@ pub fn handle_app_output(
             WindowLevel::Normal
         });
     }
+
+    if let Some(minimized) = minimized {
+        window.set_minimized(minimized);
+    }
+
+    if let Some(maximized) = maximized {
+        window.set_maximized(maximized);
+    }
 }
 
 // ----------------------------------------------------------------------------

examples/custom_window_frame/src/main.rs

@@ -10,8 +10,8 @@ fn main() -> Result<(), eframe::Error> {
         decorated: false,
         // To have rounded corners we need transparency:
         transparent: true,
-        min_window_size: Some(egui::vec2(320.0, 100.0)),
-        initial_window_size: Some(egui::vec2(320.0, 240.0)),
+        min_window_size: Some(egui::vec2(400.0, 100.0)),
+        initial_window_size: Some(egui::vec2(400.0, 240.0)),
         ..Default::default()
     };
     eframe::run_native(
@@ -22,15 +22,17 @@ fn main() -> Result<(), eframe::Error> {
 }
 
 #[derive(Default)]
-struct MyApp {}
+struct MyApp {
+    maximized: bool,
+}
 
 impl eframe::App for MyApp {
     fn clear_color(&self, _visuals: &egui::Visuals) -> [f32; 4] {
         egui::Rgba::TRANSPARENT.to_array() // Make sure we don't paint anything behind the rounded corners
     }
 
     fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
-        custom_window_frame(ctx, frame, "egui with custom frame", |ui| {
+        custom_window_frame(self, ctx, frame, "egui with custom frame", |ui| {
             ui.label("This is just the contents of the window");
             ui.horizontal(|ui| {
                 ui.label("egui theme:");
@@ -41,6 +43,7 @@ impl eframe::App for MyApp {
 }
 
 fn custom_window_frame(
+    app: &mut MyApp,
     ctx: &egui::Context,
     frame: &mut eframe::Frame,
     title: &str,
@@ -92,7 +95,11 @@ fn custom_window_frame(
             };
             let title_bar_response =
                 ui.interact(title_bar_rect, Id::new("title_bar"), Sense::click());
-            if title_bar_response.is_pointer_button_down_on() {
+
+            if title_bar_response.double_clicked() {
+                app.maximized = !app.maximized;
+                frame.set_maximized(app.maximized);
+            } else if title_bar_response.is_pointer_button_down_on() {
                 frame.drag_window();
             }
 
@@ -105,6 +112,32 @@ fn custom_window_frame(
                 frame.close();
             }
 
+            let minimized_response = ui.put(
+                Rect::from_min_size(
+                    rect.left_top() + vec2((height - 4.0) * 1.0, 0.0),
+                    Vec2::splat(height),
+                ),
+                Button::new(RichText::new("🗕").size(height - 4.0)).frame(false),
+            );
+            if minimized_response.clicked() {
+                frame.set_minimized(true);
+            }
+
+            let maximized_response = ui.put(
+                Rect::from_min_size(
+                    rect.left_top() + vec2((height - 4.0) * 2.0, 0.0),
+                    Vec2::splat(height),
+                ),
+                Button::new(
+                    RichText::new(if app.maximized { "🗗" } else { "🗖" }).size(height - 4.0),
+                )
+                .frame(false),
+            );
+            if maximized_response.clicked() {
+                app.maximized = !app.maximized;
+                frame.set_maximized(app.maximized);
+            }
+
             // Add the contents:
             let content_rect = {
                 let mut rect = rect;