Add examples/window_pump_events_rfd

The way that the `rfd` crate and Winit interact is poorly defined
and fragile.

Applications are even more likely to break assumptions if they
have an external event loop based on `pump_events`.

This example can be used to smoke test how the use of the `rfd` crate
currently interacts with applications based on an external event loop.

Author: rib

Cargo.toml

@@ -63,6 +63,9 @@ smol_str = "0.2.0"
 image = { version = "0.24.0", default-features = false, features = ["png"] }
 simple_logger = { version = "2.1.0", default_features = false }
 
+[target.'cfg(any(target_os = "windows", target_os = "macos", target_os = "linux"))'.dev-dependencies]
+rfd = { version = "0.11.0" }
+
 [target.'cfg(target_os = "android")'.dependencies]
 # Coordinate the next winit release with android-ndk-rs: https://github.com/rust-windowing/winit/issues/1995
 android-activity = "0.4.0"

examples/window_pump_events.rs

@@ -48,8 +48,11 @@ fn main() -> std::process::ExitCode {
             break 'main ExitCode::from(exit_code as u8);
         }
 
-        // Sleep for 1/60 second to simulate rendering
-        println!("rendering");
+        // Sleep for 1/60 second to simulate application work
+        //
+        // Since `pump_events` doesn't block it will be important to
+        // throttle the loop in the app somehow.
+        println!("Update()");
         sleep(Duration::from_millis(16));
     }
 }

examples/window_pump_events_rfd.rs

@@ -0,0 +1,61 @@
+#![allow(clippy::single_match)]
+
+// Limit this example to only compatible platforms.
+#[cfg(any(windows_platform, macos_platform, x11_platform, wayland_platform,))]
+fn main() -> std::process::ExitCode {
+    use std::{process::ExitCode, thread::sleep, time::Duration};
+
+    use simple_logger::SimpleLogger;
+    use winit::{
+        event::{Event, PumpStatus, WindowEvent},
+        event_loop::EventLoop,
+        platform::pump_events::EventLoopExtPumpEvents,
+        window::WindowBuilder,
+    };
+    let mut event_loop = EventLoop::new();
+
+    SimpleLogger::new().init().unwrap();
+    let window = WindowBuilder::new()
+        .with_title("A fantastic window!")
+        .build(&event_loop)
+        .unwrap();
+
+    'main: loop {
+        let status = event_loop.pump_events(|event, _, control_flow| {
+            if let Event::WindowEvent { event, .. } = &event {
+                // Print only Window events to reduce noise
+                println!("{:?}", event);
+            }
+
+            match event {
+                Event::WindowEvent {
+                    event: WindowEvent::CloseRequested,
+                    window_id,
+                } if window_id == window.id() => control_flow.set_exit(),
+                Event::MainEventsCleared => {
+                    window.request_redraw();
+                }
+                _ => (),
+            }
+        });
+        if let PumpStatus::Exit(exit_code) = status {
+            break 'main ExitCode::from(exit_code as u8);
+        }
+
+        // Sleep for 1/60 second to simulate rendering
+        println!("rendering");
+
+        let _dialog = rfd::MessageDialog::new()
+            .set_title("Msg!")
+            .set_description("Description!")
+            .set_buttons(rfd::MessageButtons::YesNo)
+            .show();
+
+        sleep(Duration::from_millis(33));
+    }
+}
+
+#[cfg(any(target_os = "ios", target_arch = "wasm32"))]
+fn main() {
+    println!("This platform doesn't support pump_events.");
+}