Implement ModifiersChanged on Windows, and fix bugs discovered in implementation process

CHANGELOG.md

@@ -16,7 +16,11 @@
   - `RedrawEventsCleared` is issued after each set of `RedrawRequested` events.
 - Implement synthetic window focus key events on Windows.
 - **Breaking**: Change `ModifiersState` to a `bitflags` struct.
+- On Windows, implement `VirtualKeyCode` translation for `LWin` and `RWin`.
+- On Windows, fix closing the last opened window causing `DeviceEvent`s to stop getting emitted.
 - On Windows, fix `Window::set_visible` not setting internal flags correctly. This resulted in some weird behavior.
+- Add `DeviceEvent::ModifiersChanged`.
+  - Deprecate `modifiers` fields in other events in favor of `ModifiersChanged`.
 
 # 0.20.0 Alpha 5 (2019-12-09)
 

examples/cursor_grab.rs

@@ -1,5 +1,5 @@
 use winit::{
-    event::{DeviceEvent, ElementState, Event, KeyboardInput, WindowEvent},
+    event::{DeviceEvent, ElementState, Event, KeyboardInput, ModifiersState, WindowEvent},
     event_loop::{ControlFlow, EventLoop},
     window::WindowBuilder,
 };
@@ -12,6 +12,8 @@ fn main() {
         .build(&event_loop)
         .unwrap();
 
+    let mut modifiers = ModifiersState::default();
+
     event_loop.run(move |event, _, control_flow| {
         *control_flow = ControlFlow::Wait;
         match event {
@@ -22,7 +24,6 @@ fn main() {
                         KeyboardInput {
                             state: ElementState::Released,
                             virtual_keycode: Some(key),
-                            modifiers,
                             ..
                         },
                     ..
@@ -43,6 +44,7 @@ fn main() {
                     ElementState::Pressed => println!("mouse button {} pressed", button),
                     ElementState::Released => println!("mouse button {} released", button),
                 },
+                DeviceEvent::ModifiersChanged(m) => modifiers = m,
                 _ => (),
             },
             _ => (),

src/event.rs

@@ -167,6 +167,7 @@ pub enum WindowEvent {
         /// limited by the display area and it may have been transformed by the OS to implement effects such as cursor
         /// acceleration, it should not be used to implement non-cursor-like interactions such as 3D camera control.
         position: LogicalPosition,
+        #[deprecated = "Deprecated in favor of DeviceEvent::ModifiersChanged"]
         modifiers: ModifiersState,
     },
 
@@ -181,6 +182,7 @@ pub enum WindowEvent {
         device_id: DeviceId,
         delta: MouseScrollDelta,
         phase: TouchPhase,
+        #[deprecated = "Deprecated in favor of DeviceEvent::ModifiersChanged"]
         modifiers: ModifiersState,
     },
 
@@ -189,6 +191,7 @@ pub enum WindowEvent {
         device_id: DeviceId,
         state: ElementState,
         button: MouseButton,
+        #[deprecated = "Deprecated in favor of DeviceEvent::ModifiersChanged"]
         modifiers: ModifiersState,
     },
 
@@ -295,11 +298,15 @@ pub enum DeviceEvent {
 
     Key(KeyboardInput),
 
-    /// Keyboard modifiers have changed
-    #[doc(hidden)]
-    ModifiersChanged {
-        modifiers: ModifiersState,
-    },
+    /// The keyboard modifiers have changed.
+    ///
+    /// This is tracked internally to avoid tracking errors arising from modifier key state changes when events from
+    /// this device are not being delivered to the application, e.g. due to keyboard focus being elsewhere.
+    ///
+    /// Platform-specific behavior:
+    /// - **Web**: This API is currently unimplemented on the web. This isn't by design - it's an
+    ///   issue, and it should get fixed - but it's the current state of the API.
+    ModifiersChanged(ModifiersState),
 
     Text {
         codepoint: char,
@@ -329,6 +336,7 @@ pub struct KeyboardInput {
     ///
     /// This is tracked internally to avoid tracking errors arising from modifier key state changes when events from
     /// this device are not being delivered to the application, e.g. due to keyboard focus being elsewhere.
+    #[deprecated = "Deprecated in favor of DeviceEvent::ModifiersChanged"]
     pub modifiers: ModifiersState,
 }
 

src/platform_impl/linux/wayland/keyboard.rs

@@ -105,7 +105,7 @@ pub fn init_keyboard(
                     my_sink
                         .send(Event::DeviceEvent {
                             device_id: device_id(),
-                            event: DeviceEvent::ModifiersChanged { modifiers },
+                            event: DeviceEvent::ModifiersChanged(modifiers),
                         })
                         .unwrap();
                 }

src/platform_impl/linux/x11/event_processor.rs

@@ -137,7 +137,7 @@ impl<T: 'static> EventProcessor<T> {
                             let device_id = mkdid(util::VIRTUAL_CORE_KEYBOARD);
                             callback(Event::DeviceEvent {
                                 device_id,
-                                event: DeviceEvent::ModifiersChanged { modifiers },
+                                event: DeviceEvent::ModifiersChanged(modifiers),
                             });
                         }
                     }
@@ -1114,9 +1114,7 @@ impl<T: 'static> EventProcessor<T> {
                             if modifiers != new_modifiers {
                                 callback(Event::DeviceEvent {
                                     device_id,
-                                    event: DeviceEvent::ModifiersChanged {
-                                        modifiers: new_modifiers,
-                                    },
+                                    event: DeviceEvent::ModifiersChanged(new_modifiers),
                                 });
                             }
                         }

src/platform_impl/macos/view.rs

@@ -688,9 +688,7 @@ extern "C" fn flags_changed(this: &Object, _sel: Sel, event: id) {
 
         AppState::queue_event(Event::DeviceEvent {
             device_id: DEVICE_ID,
-            event: DeviceEvent::ModifiersChanged {
-                modifiers: state.modifiers,
-            },
+            event: DeviceEvent::ModifiersChanged(state.modifiers),
         });
     }
     trace!("Completed `flagsChanged`");

src/platform_impl/windows/event.rs

@@ -36,6 +36,55 @@ pub fn get_key_mods() -> ModifiersState {
     mods
 }
 
+bitflags! {
+    #[derive(Default)]
+    pub struct ModifiersStateSide: u32 {
+        const LSHIFT = 0b010 << 0;
+        const RSHIFT = 0b001 << 0;
+
+        const LCTRL = 0b010 << 3;
+        const RCTRL = 0b001 << 3;
+
+        const LALT = 0b010 << 6;
+        const RALT = 0b001 << 6;
+
+        const LLOGO = 0b010 << 9;
+        const RLOGO = 0b001 << 9;
+    }
+}
+
+impl ModifiersStateSide {
+    pub fn filter_out_altgr(&self) -> ModifiersStateSide {
+        match layout_uses_altgr() && self.contains(Self::RALT) {
+            false => *self,
+            true => *self & !(Self::LCTRL | Self::RCTRL | Self::LALT | Self::RALT),
+        }
+    }
+}
+
+impl From<ModifiersStateSide> for ModifiersState {
+    fn from(side: ModifiersStateSide) -> Self {
+        let mut state = ModifiersState::default();
+        state.set(
+            Self::SHIFT,
+            side.intersects(ModifiersStateSide::LSHIFT | ModifiersStateSide::RSHIFT),
+        );
+        state.set(
+            Self::CTRL,
+            side.intersects(ModifiersStateSide::LCTRL | ModifiersStateSide::RCTRL),
+        );
+        state.set(
+            Self::ALT,
+            side.intersects(ModifiersStateSide::LALT | ModifiersStateSide::RALT),
+        );
+        state.set(
+            Self::LOGO,
+            side.intersects(ModifiersStateSide::LLOGO | ModifiersStateSide::RLOGO),
+        );
+        state
+    }
+}
+
 pub fn get_pressed_keys() -> impl Iterator<Item = c_int> {
     let mut keyboard_state = vec![0u8; 256];
     unsafe { winuser::GetKeyboardState(keyboard_state.as_mut_ptr()) };
@@ -196,8 +245,8 @@ pub fn vkey_to_winit_vkey(vkey: c_int) -> Option<VirtualKeyCode> {
         0x58 => Some(VirtualKeyCode::X),
         0x59 => Some(VirtualKeyCode::Y),
         0x5A => Some(VirtualKeyCode::Z),
-        //winuser::VK_LWIN => Some(VirtualKeyCode::Lwin),
-        //winuser::VK_RWIN => Some(VirtualKeyCode::Rwin),
+        winuser::VK_LWIN => Some(VirtualKeyCode::LWin),
+        winuser::VK_RWIN => Some(VirtualKeyCode::RWin),
         winuser::VK_APPS => Some(VirtualKeyCode::Apps),
         winuser::VK_SLEEP => Some(VirtualKeyCode::Sleep),
         winuser::VK_NUMPAD0 => Some(VirtualKeyCode::Numpad0),