3 files changed, 34 insertions, 2 deletions

diff --git a/src/lib.rs b/src/lib.rs
index acf8287..1da2e91 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,7 +5,7 @@ mod window_program;
 mod phosphor;
 
 pub use events::{Request, Event, Action, Axis, MouseButton, SizeBounds};
-pub(crate) use window::PhosphorWindow;
+pub(crate) use window::{PhosphorWindow, PointerState};
 pub use window_builder::WindowBuilder;
 pub use window_program::WindowProgram;
 
diff --git a/src/phosphor.rs b/src/phosphor.rs
index ab13cb0..08c71da 100644
--- a/src/phosphor.rs
+++ b/src/phosphor.rs
@@ -134,10 +134,16 @@ impl PhosphorApplication {
                 }
             }
             WindowEvent::CursorEntered { .. } => {
+                window.pointer_state = PointerState::In;
                 handle!(Event::CursorEnter);
             }
             WindowEvent::CursorLeft { .. } => {
-                handle!(Event::CursorExit);
+                if window.mouse_buttons.iter().all(|b| !b) {
+                    window.pointer_state = PointerState::Out;
+                    handle!(Event::CursorExit);
+                } else {
+                    window.pointer_state = PointerState::PendingOut;
+                }
             }
             WindowEvent::MouseWheel { delta, .. } => match delta {
                 MouseScrollDelta::LineDelta(x, y) => {
@@ -159,6 +165,20 @@ impl PhosphorApplication {
                     WinitMouseButton::Forward => handle!(Event::MouseButton { button: MouseButton::Forward, action }),
                     _ => (),
                 }
+                // Keep track of mouse button hold states, and mark cursor as out when all are released.
+                let button_index = match button {
+                    WinitMouseButton::Left    => 0,
+                    WinitMouseButton::Middle  => 1,
+                    WinitMouseButton::Right   => 2,
+                    WinitMouseButton::Back    => 3,
+                    WinitMouseButton::Forward => 4,
+                    _ => return,
+                };
+                window.mouse_buttons[button_index] = action.is_pressed();
+                if window.pointer_state == PointerState::PendingOut && window.mouse_buttons.iter().all(|b| !b) {
+                    window.pointer_state = PointerState::Out;
+                    handle!(Event::CursorExit);
+                }
             }
             WindowEvent::RedrawRequested => {
                 window.redraw();
diff --git a/src/window.rs b/src/window.rs
index 70c9c02..f031af5 100644
--- a/src/window.rs
+++ b/src/window.rs
@@ -18,11 +18,21 @@ fn to_physical_size(dimensions: Dimensions, scale: u32) -> PhysicalSize<u32> {
 }
 
 
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum PointerState {
+    In,
+    Out,
+    PendingOut,
+}
+
+
 pub(crate) struct PhosphorWindow {
     pub winit: Rc<Window>,
     pub program: Box<dyn WindowProgram>,
     pub requests: EventQueue<Request>,
     pub pointer: Option<Position>,
+    pub pointer_state: PointerState,
+    pub mouse_buttons: [bool; 5],
     pub marked_for_destruction: bool,
     pub size_bounds: SizeBounds,  // logical dimensions
 
@@ -79,6 +89,8 @@ impl PhosphorWindow {
             program: builder.program,
             requests: EventQueue::new(),
             pointer: None,
+            pointer_state: PointerState::Out,
+            mouse_buttons: [false; 5],
             marked_for_destruction: false,
             size_bounds,