Add RawMouseEvent which allows negative positions (fixes a bug)

Since the mouse position is relative to the origin of a widget,
mouse positions can be negative, previously they were clamped to 0,
which led to "always hovering" situations even if the mouse was above,
or left to a widget. This should fix the issue.

src/app.rs

@@ -177,7 +177,7 @@ impl<T: Send + 'static, V: View<T> + 'static> App<T, V> {
                             code: KeyCode::Esc, ..
                         })) => Event::Quit,
                         Ok(CxEvent::Key(key_event)) => Event::Key(key_event),
-                        Ok(CxEvent::Mouse(mouse_event)) => Event::Mouse(mouse_event),
+                        Ok(CxEvent::Mouse(mouse_event)) => Event::Mouse(mouse_event.into()),
                         Ok(CxEvent::FocusGained) => Event::FocusGained,
                         Ok(CxEvent::FocusLost) => Event::FocusLost,
                         // CxEvent::Paste(_) => todo!(),

src/widget.rs

@@ -15,8 +15,7 @@ mod text;
 mod weighted_linear_layout;
 
 pub use self::core::{
-    AnyWidget, ChangeFlags, CxState, Event, EventCx, LayoutCx, LifeCycleCx, Message, PaintCx, Pod,
-    Widget,
+    AnyWidget, ChangeFlags, CxState, EventCx, LayoutCx, LifeCycleCx, Message, PaintCx, Pod, Widget,
 };
 pub(crate) use self::core::{PodFlags, WidgetState};
 pub(crate) use border::Border;

src/widget/core.rs

@@ -1,8 +1,7 @@
-use super::{BoxConstraints, LifeCycle};
+use super::{BoxConstraints, Event, LifeCycle};
 use crate::geometry::{Point, Rect, Size};
 use bitflags::bitflags;
-pub use crossterm::event::MouseEvent;
-use crossterm::event::{KeyEvent, MouseEventKind};
+use crossterm::event::MouseEventKind;
 use ratatui::Terminal;
 use std::{any::Any, ops::DerefMut};
 use xilem_core::{message, Id};
@@ -18,24 +17,6 @@ use std::io::Stdout;
 
 message!(Send);
 
-#[derive(Debug, Clone)]
-pub enum Event {
-    /// Only sent once at the start of the application
-    Start,
-    Quit,
-    /// Sent e.g. when a future requests waking up the application
-    Wake,
-    FocusLost,
-    FocusGained,
-    Resize {
-        width: u16,
-        height: u16,
-    },
-    // TODO create a custom type...
-    Mouse(MouseEvent),
-    Key(KeyEvent),
-}
-
 /// Static state that is shared between most contexts.
 pub struct CxState<'a> {
     messages: &'a mut Vec<Message>,
@@ -471,8 +452,8 @@ impl Pod {
                 {
                     let mut mouse_event = *mouse_event;
                     let (x, y) = (
-                        self.state.origin.x.round() as u16,
-                        self.state.origin.y.round() as u16,
+                        self.state.origin.x.round() as i16,
+                        self.state.origin.y.round() as i16,
                     );
                     mouse_event.column = mouse_event.column.saturating_sub(x);
                     mouse_event.row = mouse_event.row.saturating_sub(y);

src/widget/events.rs

@@ -7,9 +7,26 @@ use ratatui::style::Style;
 
 use super::{
     core::{IdPath, PaintCx},
-    Event, EventCx, LayoutCx, Message, Pod, Widget,
+    EventCx, LayoutCx, Message, Pod, Widget,
 };
 
+#[derive(Debug, Clone)]
+pub enum Event {
+    /// Only sent once at the start of the application
+    Start,
+    Quit,
+    /// Sent e.g. when a future requests waking up the application
+    Wake,
+    FocusLost,
+    FocusGained,
+    Resize {
+        width: u16,
+        height: u16,
+    },
+    Mouse(RawMouseEvent),
+    Key(crossterm::event::KeyEvent),
+}
+
 #[derive(Debug)]
 pub enum LifeCycle {
     HotChanged(bool),
@@ -24,6 +41,25 @@ pub struct ViewContext {
     pub mouse_position: Option<Point>,
 }
 
+#[derive(Debug, PartialOrd, PartialEq, Eq, Clone, Copy, Hash)]
+pub struct RawMouseEvent {
+    pub kind: MouseEventKind,
+    pub column: i16,
+    pub row: i16,
+    pub modifiers: crossterm::event::KeyModifiers,
+}
+
+impl From<crossterm::event::MouseEvent> for RawMouseEvent {
+    fn from(event: crossterm::event::MouseEvent) -> Self {
+        RawMouseEvent {
+            kind: event.kind,
+            column: event.column as i16,
+            row: event.row as i16,
+            modifiers: event.modifiers,
+        }
+    }
+}
+
 impl ViewContext {
     pub fn translate_to(&self, new_origin: Point) -> ViewContext {
         // TODO I think the clip calculation is buggy in xilem (width/height?)
@@ -42,19 +78,21 @@ impl ViewContext {
     }
 }
 
+// TODO separate the widgets etc. into its own module?
+
 #[derive(Debug)]
 /// A message representing a mouse event.
 pub struct MouseEvent {
     pub over_element: bool,
     pub is_active: bool,
     pub kind: MouseEventKind,
-    pub column: u16,
-    pub row: u16,
+    pub column: i16,
+    pub row: i16,
     pub modifiers: crossterm::event::KeyModifiers,
 }
 
 impl MouseEvent {
-    fn new(event: crossterm::event::MouseEvent, over_element: bool, is_active: bool) -> Self {
+    fn new(event: RawMouseEvent, over_element: bool, is_active: bool) -> Self {
         MouseEvent {
             over_element,
             is_active,
@@ -108,7 +146,7 @@ impl<E: Widget> Widget for OnMouse<E> {
 
         match event {
             Event::Mouse(
-                event @ crossterm::event::MouseEvent {
+                event @ RawMouseEvent {
                     kind: MouseEventKind::Down(button),
                     ..
                 },
@@ -128,7 +166,7 @@ impl<E: Widget> Widget for OnMouse<E> {
                     ));
                 }
             }
-            Event::Mouse(event @ crossterm::event::MouseEvent { kind, .. }) => {
+            Event::Mouse(event @ RawMouseEvent { kind, .. }) => {
                 let is_active = cx.is_active();
                 if matches!(kind, MouseEventKind::Up(_)) {
                     cx.set_active(false);
@@ -188,7 +226,7 @@ impl<E: Widget> Widget for OnClick<E> {
     fn event(&mut self, cx: &mut EventCx, event: &Event) {
         self.element.event(cx, event);
 
-        if let Event::Mouse(crossterm::event::MouseEvent {
+        if let Event::Mouse(RawMouseEvent {
             kind: MouseEventKind::Down(MouseButton::Left),
             ..
         }) = event
@@ -197,7 +235,7 @@ impl<E: Widget> Widget for OnClick<E> {
         }
 
         // TODO handle other events like e.g. FocusLost
-        if let Event::Mouse(crossterm::event::MouseEvent {
+        if let Event::Mouse(RawMouseEvent {
             kind: MouseEventKind::Up(MouseButton::Left),
             ..
         }) = event
@@ -374,14 +412,14 @@ impl Widget for StyleOnPressed {
         self.element.event(cx, event);
 
         match event {
-            Event::Mouse(crossterm::event::MouseEvent {
+            Event::Mouse(RawMouseEvent {
                 kind: MouseEventKind::Down(MouseButton::Left),
                 ..
             }) => {
                 cx.request_paint();
                 cx.set_active(cx.is_hot());
             }
-            Event::Mouse(crossterm::event::MouseEvent {
+            Event::Mouse(RawMouseEvent {
                 kind: MouseEventKind::Up(MouseButton::Left) | MouseEventKind::Moved,
                 ..
             })