Add basic drag and drop support

Cargo.toml

@@ -165,6 +165,10 @@ path = "examples/app/return_after_run.rs"
 name = "thread_pool_resources"
 path = "examples/app/thread_pool_resources.rs"
 
+[[example]]
+name = "draganddrop"
+path = "examples/app/draganddrop.rs"
+
 [[example]]
 name = "hot_asset_reloading"
 path = "examples/asset/hot_asset_reloading.rs"

crates/bevy_window/src/event.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use super::{WindowDescriptor, WindowId};
 use bevy_math::Vec2;
 
@@ -64,3 +66,20 @@ pub struct WindowFocused {
     pub id: WindowId,
     pub focused: bool,
 }
+
+#[derive(Debug, Clone)]
+pub struct DroppedFile {
+    pub id: WindowId,
+    pub path_buf: PathBuf,
+}
+
+#[derive(Debug, Clone)]
+pub struct HoveredFile {
+    pub id: WindowId,
+    pub path_buf: PathBuf,
+}
+
+#[derive(Debug, Clone)]
+pub struct HoveredFileCancelled {
+    pub id: WindowId,
+}

crates/bevy_window/src/lib.rs

@@ -11,8 +11,8 @@ pub use windows::*;
 
 pub mod prelude {
     pub use crate::{
-        CursorEntered, CursorLeft, CursorMoved, ReceivedCharacter, Window, WindowDescriptor,
-        Windows,
+        CursorEntered, CursorLeft, CursorMoved, DroppedFile, HoveredFile, HoveredFileCancelled,
+        ReceivedCharacter, Window, WindowDescriptor, Windows,
     };
 }
 
@@ -44,6 +44,9 @@ impl Plugin for WindowPlugin {
             .add_event::<CursorLeft>()
             .add_event::<ReceivedCharacter>()
             .add_event::<WindowFocused>()
+            .add_event::<DroppedFile>()
+            .add_event::<HoveredFile>()
+            .add_event::<HoveredFileCancelled>()
             .init_resource::<Windows>();
 
         if self.add_primary_window {

crates/bevy_winit/src/lib.rs

@@ -14,8 +14,9 @@ use bevy_ecs::{IntoSystem, Resources, World};
 use bevy_math::Vec2;
 use bevy_utils::tracing::{error, trace};
 use bevy_window::{
-    CreateWindow, CursorEntered, CursorLeft, CursorMoved, ReceivedCharacter, WindowCloseRequested,
-    WindowCreated, WindowFocused, WindowResized, Windows,
+    CreateWindow, CursorEntered, CursorLeft, CursorMoved, DroppedFile, HoveredFile,
+    HoveredFileCancelled, ReceivedCharacter, WindowCloseRequested, WindowCreated, WindowFocused,
+    WindowResized, Windows,
 };
 use winit::{
     event::{self, DeviceEvent, Event, WindowEvent},
@@ -350,6 +351,35 @@ pub fn winit_runner(mut app: App) {
                         ),
                     }
                 }
+                WindowEvent::DroppedFile(path_buf) => {
+                    let mut cursor_left_events =
+                        app.resources.get_mut::<Events<DroppedFile>>().unwrap();
+                    let winit_windows = app.resources.get_mut::<WinitWindows>().unwrap();
+                    let window_id = winit_windows.get_window_id(winit_window_id).unwrap();
+                    cursor_left_events.send(DroppedFile {
+                        id: window_id,
+                        path_buf,
+                    });
+                }
+                WindowEvent::HoveredFile(path_buf) => {
+                    let mut cursor_left_events =
+                        app.resources.get_mut::<Events<HoveredFile>>().unwrap();
+                    let winit_windows = app.resources.get_mut::<WinitWindows>().unwrap();
+                    let window_id = winit_windows.get_window_id(winit_window_id).unwrap();
+                    cursor_left_events.send(HoveredFile {
+                        id: window_id,
+                        path_buf,
+                    });
+                }
+                WindowEvent::HoveredFileCancelled => {
+                    let mut cursor_left_events = app
+                        .resources
+                        .get_mut::<Events<HoveredFileCancelled>>()
+                        .unwrap();
+                    let winit_windows = app.resources.get_mut::<WinitWindows>().unwrap();
+                    let window_id = winit_windows.get_window_id(winit_window_id).unwrap();
+                    cursor_left_events.send(HoveredFileCancelled { id: window_id });
+                }
                 _ => {}
             },
             event::Event::DeviceEvent {
@@ -370,6 +400,7 @@ pub fn winit_runner(mut app: App) {
                 );
                 app.update();
             }
+
             _ => (),
         }
     };

examples/README.md

@@ -80,6 +80,7 @@ Example | File | Description
 Example | File | Description
 --- | --- | ---
 `custom_loop` | [`app/custom_loop.rs`](./app/custom_loop.rs) | Demonstrates how to create a custom runner (to update an app manually).
+`draganddrop` | [`app/empty_defaults.rs`](./app/draganddrop.rs) | An example that shows how to handle drag and drop in an app.
 `empty_defaults` | [`app/empty_defaults.rs`](./app/empty_defaults.rs) | An empty application with default plugins
 `empty` | [`app/empty.rs`](./app/empty.rs) | An empty application (does nothing)
 `headless` | [`app/headless.rs`](./app/headless.rs) | An application that runs without default plugins

examples/app/draganddrop.rs

@@ -0,0 +1,37 @@
+use bevy::prelude::*;
+
+#[derive(Default)]
+struct DroppedFileSystemState {
+    dropped_filed_event_reader: EventReader<DroppedFile>,
+    hovered_file_event_reader: EventReader<HoveredFile>,
+    hovered_file_canceled_event_reader: EventReader<HoveredFileCancelled>,
+}
+
+fn main() {
+    App::build()
+        .add_plugins(DefaultPlugins)
+        .add_system(dropped_file_system.system())
+        .run();
+}
+
+fn dropped_file_system(
+    mut state: Local<DroppedFileSystemState>,
+    dropped_file_events: Res<Events<DroppedFile>>,
+    hovered_file_events: Res<Events<HoveredFile>>,
+    hovered_file_canceled_events: Res<Events<HoveredFileCancelled>>,
+) {
+    for event in state.dropped_filed_event_reader.iter(&dropped_file_events) {
+        println!("Dropped file{:?}", event);
+    }
+
+    for event in state.hovered_file_event_reader.iter(&hovered_file_events) {
+        println!("Hovered file{:?}", event);
+    }
+
+    for event in state
+        .hovered_file_canceled_event_reader
+        .iter(&hovered_file_canceled_events)
+    {
+        println!("Dropped file{:?}", event);
+    }
+}