Add mouse move events to `MouseArea`

1 files changed, 73 insertions, 2 deletions

diff --git a/widget/src/mouse_area.rs b/widget/src/mouse_area.rs
index 88f7d126..1487aaa5 100644
--- a/widget/src/mouse_area.rs
+++ b/widget/src/mouse_area.rs
@@ -1,5 +1,7 @@
 //! A container for capturing mouse events.
 
+use iced_renderer::core::Point;
+
 use crate::core::event::{self, Event};
 use crate::core::layout;
 use crate::core::mouse;
@@ -26,6 +28,9 @@ pub struct MouseArea<
     on_right_release: Option<Message>,
     on_middle_press: Option<Message>,
     on_middle_release: Option<Message>,
+    on_mouse_enter: Option<Message>,
+    on_mouse_move: Option<Box<dyn FnMut(Point) -> Message>>,
+    on_mouse_exit: Option<Message>,
 }
 
 impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
@@ -70,12 +75,36 @@ impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
         self.on_middle_release = Some(message);
         self
     }
+
+    /// The message to emit when the mouse enters the area.
+    #[must_use]
+    pub fn on_mouse_enter(mut self, message: Message) -> Self {
+        self.on_mouse_enter = Some(message);
+        self
+    }
+
+    /// The message to emit when the mouse moves in the area.
+    #[must_use]
+    pub fn on_mouse_move<F>(mut self, build_message: F) -> Self
+    where
+        F: FnMut(Point) -> Message + 'static,
+    {
+        self.on_mouse_move = Some(Box::new(build_message));
+        self
+    }
+
+    /// The message to emit when the mouse exits the area.
+    #[must_use]
+    pub fn on_mouse_exit(mut self, message: Message) -> Self {
+        self.on_mouse_exit = Some(message);
+        self
+    }
 }
 
 /// Local state of the [`MouseArea`].
 #[derive(Default)]
 struct State {
-    // TODO: Support on_mouse_enter and on_mouse_exit
+    mouse_in_area: bool,
 }
 
 impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
@@ -91,6 +120,9 @@ impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
             on_right_release: None,
             on_middle_press: None,
             on_middle_release: None,
+            on_mouse_enter: None,
+            on_mouse_move: None,
+            on_mouse_exit: None,
         }
     }
 }
@@ -171,7 +203,7 @@ where
             return event::Status::Captured;
         }
 
-        update(self, &event, layout, cursor, shell)
+        update(self, tree, &event, layout, cursor, shell)
     }
 
     fn mouse_interaction(
@@ -246,11 +278,19 @@ where
 /// accordingly.
 fn update<Message: Clone, Theme, Renderer>(
     widget: &mut MouseArea<'_, Message, Theme, Renderer>,
+    tree: &mut Tree,
     event: &Event,
     layout: Layout<'_>,
     cursor: mouse::Cursor,
     shell: &mut Shell<'_, Message>,
 ) -> event::Status {
+    if let Event::Mouse(mouse::Event::CursorMoved { position })
+    | Event::Touch(touch::Event::FingerMoved { id: _, position }) = event
+    {
+        let state: &mut State = tree.state.downcast_mut();
+        handle_mouse_move(widget, state, shell, *position, layout.bounds())
+    }
+
     if !cursor.is_over(layout.bounds()) {
         return event::Status::Ignored;
     }
@@ -320,3 +360,34 @@ fn update<Message: Clone, Theme, Renderer>(
 
     event::Status::Ignored
 }
+
+fn handle_mouse_move<Message: Clone, Theme, Renderer>(
+    widget: &mut MouseArea<'_, Message, Theme, Renderer>,
+    state: &mut State,
+    shell: &mut Shell<'_, Message>,
+    position: Point,
+    area_bounds: Rectangle,
+) {
+    let mouse_in_area = area_bounds.contains(position);
+
+    match (
+        widget.on_mouse_enter.as_mut(),
+        widget.on_mouse_move.as_mut(),
+        widget.on_mouse_exit.as_mut(),
+    ) {
+        (Some(enter_msg), _, _) if mouse_in_area && !state.mouse_in_area => {
+            shell.publish(enter_msg.clone())
+        }
+        (_, Some(build_move_msg), _)
+            if mouse_in_area && state.mouse_in_area =>
+        {
+            shell.publish(build_move_msg(position))
+        }
+        (_, _, Some(exit_msg)) if !mouse_in_area && state.mouse_in_area => {
+            shell.publish(exit_msg.clone())
+        }
+        _ => {}
+    }
+
+    state.mouse_in_area = mouse_in_area;
+}