Fix Oval::is_over to correctly distinguish between OvalSections

src/widget/primitive/shape/oval.rs

@@ -23,15 +23,20 @@ pub struct Oval<S> {
 }
 
 /// Types that may be used to describe the visible section of the `Oval`.
-pub trait OvalSection: 'static + Copy + PartialEq + Send {}
+pub trait OvalSection: 'static + Copy + PartialEq + Send {
+    /// The function used to determine if a point is over the oval section widget.
+    const IS_OVER: widget::IsOverFn;
+}
 
 /// The entire `Oval` will be drawn.
 ///
 /// To draw only a section of the oval, use the `section` builder method.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub struct Full;
 
-impl OvalSection for Full {}
+impl OvalSection for Full {
+    const IS_OVER: widget::IsOverFn = is_over_widget;
+}
 
 /// A section of the oval will be drawn where the section is specified by the given radians.
 ///
@@ -46,7 +51,9 @@ pub struct Section {
     pub offset_radians: Scalar,
 }
 
-impl OvalSection for Section {}
+impl OvalSection for Section {
+    const IS_OVER: widget::IsOverFn = is_over_section_widget;
+}
 
 /// Unique state for the **Oval**.
 #[derive(Copy, Clone, Debug, PartialEq)]
@@ -141,14 +148,17 @@ where
     }
 
     fn is_over(&self) -> widget::IsOverFn {
-        is_over_widget
+        S::IS_OVER
     }
 
     fn update(self, args: widget::UpdateArgs<Self>) -> Self::Event {
         let widget::UpdateArgs { state, .. } = args;
         if state.resolution != self.resolution {
             state.update(|state| state.resolution = self.resolution);
         }
+        if state.section != self.section {
+            state.update(|state| state.section = self.section);
+        }
     }
 }
 
@@ -305,3 +315,24 @@ pub fn is_over(r: Rect, p: Point) -> bool {
 pub fn is_over_widget(widget: &graph::Container, point: Point, _: &Theme) -> widget::IsOver {
     is_over(widget.rect, point).into()
 }
+
+/// Returns whether or not the given point is over the section described
+pub fn is_over_section(circumference: Circumference, p: Point) -> bool {
+    widget::triangles::is_over(circumference.triangles(), p)
+}
+
+/// The function to use for picking whether a given point is over the oval section.
+pub fn is_over_section_widget(widget: &graph::Container, p: Point, _: &Theme) -> widget::IsOver {
+    widget
+        .state_and_style::<State<Section>, Style>()
+        .map(|unique| {
+            let res = unique.state.resolution;
+            let offset_rad = unique.state.section.offset_radians;
+            let rad = unique.state.section.radians;
+            let circumference = Circumference::new_section(widget.rect, res, rad)
+                .offset_radians(offset_rad);
+            is_over_section(circumference, p)
+        })
+        .unwrap_or_else(|| widget.rect.is_over(p))
+        .into()
+}