Implement basic cursor availability

8 files changed, 105 insertions, 104 deletions

diff --git a/core/src/element.rs b/core/src/element.rs
index 98c53737..3268f14b 100644
--- a/core/src/element.rs
+++ b/core/src/element.rs
@@ -5,9 +5,7 @@ use crate::overlay;
 use crate::renderer;
 use crate::widget;
 use crate::widget::tree::{self, Tree};
-use crate::{
-    Clipboard, Color, Layout, Length, Point, Rectangle, Shell, Widget,
-};
+use crate::{Clipboard, Color, Layout, Length, Rectangle, Shell, Widget};
 
 use std::any::Any;
 use std::borrow::Borrow;
@@ -378,7 +376,7 @@ where
         tree: &mut Tree,
         event: Event,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         renderer: &Renderer,
         clipboard: &mut dyn Clipboard,
         shell: &mut Shell<'_, B>,
@@ -390,7 +388,7 @@ where
             tree,
             event,
             layout,
-            cursor_position,
+            cursor,
             renderer,
             clipboard,
             &mut local_shell,
@@ -408,35 +406,23 @@ where
         theme: &Renderer::Theme,
         style: &renderer::Style,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         viewport: &Rectangle,
     ) {
-        self.widget.draw(
-            tree,
-            renderer,
-            theme,
-            style,
-            layout,
-            cursor_position,
-            viewport,
-        )
+        self.widget
+            .draw(tree, renderer, theme, style, layout, cursor, viewport)
     }
 
     fn mouse_interaction(
         &self,
         tree: &Tree,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         viewport: &Rectangle,
         renderer: &Renderer,
     ) -> mouse::Interaction {
-        self.widget.mouse_interaction(
-            tree,
-            layout,
-            cursor_position,
-            viewport,
-            renderer,
-        )
+        self.widget
+            .mouse_interaction(tree, layout, cursor, viewport, renderer)
     }
 
     fn overlay<'b>(
@@ -521,20 +507,14 @@ where
         state: &mut Tree,
         event: Event,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         renderer: &Renderer,
         clipboard: &mut dyn Clipboard,
         shell: &mut Shell<'_, Message>,
     ) -> event::Status {
-        self.element.widget.on_event(
-            state,
-            event,
-            layout,
-            cursor_position,
-            renderer,
-            clipboard,
-            shell,
-        )
+        self.element
+            .widget
+            .on_event(state, event, layout, cursor, renderer, clipboard, shell)
     }
 
     fn draw(
@@ -544,7 +524,7 @@ where
         theme: &Renderer::Theme,
         style: &renderer::Style,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         viewport: &Rectangle,
     ) {
         fn explain_layout<Renderer: crate::Renderer>(
@@ -567,15 +547,9 @@ where
             }
         }
 
-        self.element.widget.draw(
-            state,
-            renderer,
-            theme,
-            style,
-            layout,
-            cursor_position,
-            viewport,
-        );
+        self.element
+            .widget
+            .draw(state, renderer, theme, style, layout, cursor, viewport);
 
         explain_layout(renderer, self.color, layout);
     }
@@ -584,17 +558,13 @@ where
         &self,
         state: &Tree,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         viewport: &Rectangle,
         renderer: &Renderer,
     ) -> mouse::Interaction {
-        self.element.widget.mouse_interaction(
-            state,
-            layout,
-            cursor_position,
-            viewport,
-            renderer,
-        )
+        self.element
+            .widget
+            .mouse_interaction(state, layout, cursor, viewport, renderer)
     }
 
     fn overlay<'b>(
diff --git a/core/src/mouse.rs b/core/src/mouse.rs
index 0c405ce6..d13a60fb 100644
--- a/core/src/mouse.rs
+++ b/core/src/mouse.rs
@@ -2,10 +2,12 @@
 pub mod click;
 
 mod button;
+mod cursor;
 mod event;
 mod interaction;
 
 pub use button::Button;
 pub use click::Click;
+pub use cursor::Cursor;
 pub use event::{Event, ScrollDelta};
 pub use interaction::Interaction;
diff --git a/core/src/mouse/cursor.rs b/core/src/mouse/cursor.rs
new file mode 100644
index 00000000..d4cb415d
--- /dev/null
+++ b/core/src/mouse/cursor.rs
@@ -0,0 +1,51 @@
+use crate::{Point, Rectangle, Vector};
+
+/// The mouse cursor state.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Cursor {
+    /// The cursor has a defined position.
+    Available(Point),
+
+    /// The cursor is currently unavailable (i.e. out of bounds or busy).
+    Unavailable,
+}
+
+impl Cursor {
+    /// Returns the absolute position of the [`Cursor`], if available.
+    pub fn position(self) -> Option<Point> {
+        match self {
+            Cursor::Available(position) => Some(position),
+            Cursor::Unavailable => None,
+        }
+    }
+
+    /// Returns the absolute position of the [`Cursor`], if available and inside
+    /// the given bounds.
+    ///
+    /// If the [`Cursor`] is not over the provided bounds, this method will
+    /// return `None`.
+    pub fn position_over(self, bounds: &Rectangle) -> Option<Point> {
+        self.position().filter(|p| bounds.contains(*p))
+    }
+
+    /// Returns the relative position of the [`Cursor`] inside the given bounds,
+    /// if available.
+    ///
+    /// If the [`Cursor`] is not over the provided bounds, this method will
+    /// return `None`.
+    pub fn position_in(self, bounds: &Rectangle) -> Option<Point> {
+        self.position_over(bounds)
+            .map(|p| p - Vector::new(bounds.x, bounds.y))
+    }
+
+    /// Returns the relative position of the [`Cursor`] from the given origin,
+    /// if available.
+    pub fn position_from(self, origin: Point) -> Option<Point> {
+        self.position().map(|p| p - Vector::new(origin.x, origin.y))
+    }
+
+    /// Returns true if the [`Cursor`] is over the given `bounds`.
+    pub fn is_over(self, bounds: &Rectangle) -> bool {
+        self.position_over(bounds).is_some()
+    }
+}
diff --git a/core/src/overlay.rs b/core/src/overlay.rs
index b9f3c735..1fa994e4 100644
--- a/core/src/overlay.rs
+++ b/core/src/overlay.rs
@@ -38,7 +38,7 @@ where
         theme: &Renderer::Theme,
         style: &renderer::Style,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
     );
 
     /// Applies a [`widget::Operation`] to the [`Overlay`].
@@ -66,7 +66,7 @@ where
         &mut self,
         _event: Event,
         _layout: Layout<'_>,
-        _cursor_position: Point,
+        _cursor: mouse::Cursor,
         _renderer: &Renderer,
         _clipboard: &mut dyn Clipboard,
         _shell: &mut Shell<'_, Message>,
@@ -80,7 +80,7 @@ where
     fn mouse_interaction(
         &self,
         _layout: Layout<'_>,
-        _cursor_position: Point,
+        _cursor: mouse::Cursor,
         _viewport: &Rectangle,
         _renderer: &Renderer,
     ) -> mouse::Interaction {
diff --git a/core/src/overlay/element.rs b/core/src/overlay/element.rs
index 237d25d1..be67fc76 100644
--- a/core/src/overlay/element.rs
+++ b/core/src/overlay/element.rs
@@ -68,35 +68,25 @@ where
         &mut self,
         event: Event,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         renderer: &Renderer,
         clipboard: &mut dyn Clipboard,
         shell: &mut Shell<'_, Message>,
     ) -> event::Status {
-        self.overlay.on_event(
-            event,
-            layout,
-            cursor_position,
-            renderer,
-            clipboard,
-            shell,
-        )
+        self.overlay
+            .on_event(event, layout, cursor, renderer, clipboard, shell)
     }
 
     /// Returns the current [`mouse::Interaction`] of the [`Element`].
     pub fn mouse_interaction(
         &self,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         viewport: &Rectangle,
         renderer: &Renderer,
     ) -> mouse::Interaction {
-        self.overlay.mouse_interaction(
-            layout,
-            cursor_position,
-            viewport,
-            renderer,
-        )
+        self.overlay
+            .mouse_interaction(layout, cursor, viewport, renderer)
     }
 
     /// Draws the [`Element`] and its children using the given [`Layout`].
@@ -106,10 +96,9 @@ where
         theme: &Renderer::Theme,
         style: &renderer::Style,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
     ) {
-        self.overlay
-            .draw(renderer, theme, style, layout, cursor_position)
+        self.overlay.draw(renderer, theme, style, layout, cursor)
     }
 
     /// Applies a [`widget::Operation`] to the [`Element`].
@@ -215,7 +204,7 @@ where
         &mut self,
         event: Event,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         renderer: &Renderer,
         clipboard: &mut dyn Clipboard,
         shell: &mut Shell<'_, B>,
@@ -226,7 +215,7 @@ where
         let event_status = self.content.on_event(
             event,
             layout,
-            cursor_position,
+            cursor,
             renderer,
             clipboard,
             &mut local_shell,
@@ -240,16 +229,12 @@ where
     fn mouse_interaction(
         &self,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         viewport: &Rectangle,
         renderer: &Renderer,
     ) -> mouse::Interaction {
-        self.content.mouse_interaction(
-            layout,
-            cursor_position,
-            viewport,
-            renderer,
-        )
+        self.content
+            .mouse_interaction(layout, cursor, viewport, renderer)
     }
 
     fn draw(
@@ -258,10 +243,9 @@ where
         theme: &Renderer::Theme,
         style: &renderer::Style,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
     ) {
-        self.content
-            .draw(renderer, theme, style, layout, cursor_position)
+        self.content.draw(renderer, theme, style, layout, cursor)
     }
 
     fn is_over(&self, layout: Layout<'_>, cursor_position: Point) -> bool {
diff --git a/core/src/overlay/group.rs b/core/src/overlay/group.rs
index 0c48df34..e770abf8 100644
--- a/core/src/overlay/group.rs
+++ b/core/src/overlay/group.rs
@@ -81,7 +81,7 @@ where
         &mut self,
         event: Event,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         renderer: &Renderer,
         clipboard: &mut dyn Clipboard,
         shell: &mut Shell<'_, Message>,
@@ -93,7 +93,7 @@ where
                 child.on_event(
                     event.clone(),
                     layout,
-                    cursor_position,
+                    cursor,
                     renderer,
                     clipboard,
                     shell,
@@ -108,17 +108,17 @@ where
         theme: &<Renderer as crate::Renderer>::Theme,
         style: &renderer::Style,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
     ) {
         for (child, layout) in self.children.iter().zip(layout.children()) {
-            child.draw(renderer, theme, style, layout, cursor_position);
+            child.draw(renderer, theme, style, layout, cursor);
         }
     }
 
     fn mouse_interaction(
         &self,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         viewport: &Rectangle,
         renderer: &Renderer,
     ) -> mouse::Interaction {
@@ -126,12 +126,7 @@ where
             .iter()
             .zip(layout.children())
             .map(|(child, layout)| {
-                child.mouse_interaction(
-                    layout,
-                    cursor_position,
-                    viewport,
-                    renderer,
-                )
+                child.mouse_interaction(layout, cursor, viewport, renderer)
             })
             .max()
             .unwrap_or_default()
diff --git a/core/src/widget.rs b/core/src/widget.rs
index 769f8659..79d86444 100644
--- a/core/src/widget.rs
+++ b/core/src/widget.rs
@@ -15,7 +15,7 @@ use crate::layout::{self, Layout};
 use crate::mouse;
 use crate::overlay;
 use crate::renderer;
-use crate::{Clipboard, Length, Point, Rectangle, Shell};
+use crate::{Clipboard, Length, Rectangle, Shell};
 
 /// A component that displays information and allows interaction.
 ///
@@ -67,7 +67,7 @@ where
         theme: &Renderer::Theme,
         style: &renderer::Style,
         layout: Layout<'_>,
-        cursor_position: Point,
+        cursor: mouse::Cursor,
         viewport: &Rectangle,
     );
 
@@ -111,7 +111,7 @@ where
         _state: &mut Tree,
         _event: Event,
         _layout: Layout<'_>,
-        _cursor_position: Point,
+        _cursor: mouse::Cursor,
         _renderer: &Renderer,
         _clipboard: &mut dyn Clipboard,
         _shell: &mut Shell<'_, Message>,
@@ -126,7 +126,7 @@ where
         &self,
         _state: &Tree,
         _layout: Layout<'_>,
-        _cursor_position: Point,
+        _cursor: mouse::Cursor,
         _viewport: &Rectangle,
         _renderer: &Renderer,
     ) -> mouse::Interaction {
diff --git a/core/src/widget/text.rs b/core/src/widget/text.rs
index 90af88b7..e934a2f5 100644
--- a/core/src/widget/text.rs
+++ b/core/src/widget/text.rs
@@ -1,12 +1,11 @@
 //! Write some text for your users to read.
 use crate::alignment;
 use crate::layout;
+use crate::mouse;
 use crate::renderer;
 use crate::text;
 use crate::widget::Tree;
-use crate::{
-    Color, Element, Layout, Length, Pixels, Point, Rectangle, Size, Widget,
-};
+use crate::{Color, Element, Layout, Length, Pixels, Rectangle, Size, Widget};
 
 use std::borrow::Cow;
 
@@ -163,7 +162,7 @@ where
         theme: &Renderer::Theme,
         style: &renderer::Style,
         layout: Layout<'_>,
-        _cursor_position: Point,
+        _cursor_position: mouse::Cursor,
         _viewport: &Rectangle,
     ) {
         draw(